Corrosion-resistant coating and cookware

Abstract

The utility model provides a corrosion-resistant coating and a pot. Wherein the corrosion-resistant coating is a ferroferric oxide layer, an iron nitride layer, an iron carbide layer or an iron carbonitride layer, the corrosion-resistant coating comprises a thermal spraying area and a remelting area stacked on the outer side of the thermal spraying area, and the remelting area serves as the surface layer of the corrosion-resistant coating. According to the corrosion-resistant coating provided by the embodiment of the invention, the surface layer is the remelting area, and the remelting area has a series of improved properties, so that the remelting area serving as the surface layer of the corrosion-resistant coating can better resist corrosion of a corrosive medium and is good in corrosion resistance, and the corrosion-resistant service life of the coating can be prolonged. The remelting area is located on the outer side of the thermal spraying area, the thermal spraying area can be protected, the risk that the thermal spraying area is corroded by a corrosive medium is reduced, the corrosion resistance and the protection effect of the whole coating are improved, the adhesive force of the coating can be enhanced through the remelting area on the surface layer, and the service life of the coating is prolonged. Therefore, the product with the corrosion-resistant coating can obtain good and lasting corrosion resistance.

Description

Technical Field

[0001] The present application relates to the field of cookware, and in particular, to a corrosion-resistant coating and a cookware. Background Art

[0002] In the cookware manufacturing industry, in order to achieve corrosion resistance and wear resistance (high hardness) of the product, chemical nitriding treatment is usually performed on the surface of the substrate to form an iron nitride film layer, high-temperature heat treatment is performed on the surface of the iron substrate to form an iron oxide film layer, or the coating surface of the cookware is sealed.

[0003] Specifically, chemical nitriding usually involves placing the substrate in a nitrogen-containing environment at 550°C-600°C for more than 5 hours. In this way, a dense layer with a thickness of 10μm-20μm and a hardness of about 1000HV can be formed, thereby obtaining a corrosion-resistant coating. However, this method has the disadvantages of high energy consumption and low efficiency. The iron substrate is subjected to high-temperature heat treatment to form a ferroferric oxide film layer, specifically, the iron atoms on the surface of the substrate are chemically converted with oxygen through a flame above 1000°C to form a ferroferric oxide film layer. Although the film layer has a certain corrosion resistance, the thickness of the film layer is limited, usually less than 5μm, so the corrosion resistance is also general, and the product is still prone to rust. In addition, the coating surface of the pot is sealed to give it a certain corrosion resistance, but the sealing operation usually uses an organic sealant, which is less safe, and the sealant is easily detached due to use, resulting in insufficient corrosion resistance.

[0004] In view of this, there is an urgent need to provide a cookware with better corrosion resistance to solve the problem of poor corrosion resistance of existing cookware. Utility Model Content

[0005] Therefore, the purpose of the present application is to provide a corrosion-resistant coating and a cookware to solve the problem of poor corrosion resistance of existing cookware.

[0006] According to a first aspect of the present application, a corrosion-resistant coating is provided, wherein the corrosion-resistant coating is a ferroferric oxide layer, an iron nitride layer, an iron carbide layer or a nitride iron carbide layer, and the corrosion-resistant coating includes a thermal spraying area and a remelting area stacked on the outside of the thermal spraying area, and the remelting area serves as a surface layer of the corrosion-resistant coating.

[0007] According to the corrosion-resistant coating provided in the embodiment of the present application, the corrosion-resistant coating is a ferroferric oxide layer, an iron nitride layer, an iron carbide layer or a nitride iron carbide layer. Due to the characteristics of the forming material itself, the corrosion-resistant coating itself has a certain corrosion resistance. The corrosion-resistant coating includes a thermal spraying area and a remelting area stacked on the outside of the thermal spraying area. The remelting area serves as the surface layer of the corrosion-resistant coating, that is, the corrosion-resistant coating includes a thermal spraying area located inside the corrosion-resistant coating and a remelting area connected to the outside of the thermal spraying area and located on the surface of the corrosion-resistant coating. The remelting area itself has improved surface hardness, smaller internal pores, good surface properties, etc. Therefore, using it as the surface layer of the corrosion-resistant coating can better resist erosion by corrosive media, has good corrosion resistance, and can extend the corrosion resistance life of the coating. The remelted area is located outside the thermal spraying area, which can also protect the thermal spraying area, reduce the risk of erosion of the thermal spraying area by corrosive media, improve the corrosion resistance and protection effect of the entire coating, and the remelted area on the surface can enhance the adhesion of the coating and reduce the risk of coating peeling or falling off. Therefore, products with this corrosion-resistant coating can obtain good and lasting corrosion resistance.

[0008] In some embodiments, the remelted area is formed at an area corresponding to a preset value inward from the surface of the corrosion-resistant coating, and the preset value is 1 / 3-1 / 2 of the thickness of the corrosion-resistant coating.

[0009] In these embodiments, the remelted area is formed at an area corresponding to a preset value inward from the surface of the corrosion-resistant coating, thereby providing a longer-term corrosion protection to increase the corrosion resistance durability of the coating. In addition, the remelted area has a certain formation thickness, which can balance the corrosion resistance of the corrosion-resistant coating and other factors, such as adhesion, surface hardness, durability, etc.

[0010] In some embodiments, the thickness of the corrosion-resistant coating is 30 μm-60 μm, and the preset value is 15 μm-25 μm.

[0011] In these embodiments, the thermal spray coating may have a thickness of 30 μm-60 μm, which can avoid the risk of separation due to thick coating and high thermal stress to a certain extent. If the thickness of the thermal spray coating is less than 30 μm, the coating is not easy to form a film and cannot completely cover the cookware substrate. If the thickness of the thermal spray coating is higher than 60 μm, the thermal stress of the coating is large and it is easy to collapse.

[0012] If the thickness of the remelted area is greater than 25μm, a higher temperature and longer time are required, which may cause the ceramic layer to be overheated, resulting in overall cracking or falling off, a decrease in the strength of the remelted area, and a risk of damage to the substrate (for example, the aluminum substrate melts and deforms, the outer surface of the stainless steel substrate is severely rusted due to oxidation, etc.); if the thickness of the remelted area is less than 15μm, the rough surface formed by thermal spraying cannot be completely flattened, resulting in the final cookware surface being too dense and rough, poor long-term corrosion resistance, and affecting later use.

[0013] When the thickness of the corrosion-resistant coating is 30μm-60μm, the thickness of the remelted area is 15μm-25μm, so that the product with the corrosion-resistant coating can be guaranteed to have good corrosion resistance, adhesion and surface hardness.

[0014] In some embodiments, the porosity of the remelted region is 0.3%-0.5%, and the pore size is 5 μm-10 μm.

[0015] In these embodiments, the pore structure limited by such porosity and pore size is relatively dense, and corrosive media are not easy to enter, and the channel for corrosive media to contact the cookware substrate can be blocked, thereby further improving the corrosion resistance.

[0016] In some embodiments, the hardness of the remelted region is 1200 HV-1750 HV.

[0017] In these embodiments, the remelted area has improved hardness, and thus has good wear and scratch resistance, thereby extending the service life of the corrosion-resistant coating.

[0018] In some embodiments, the surface roughness of the remelted region is 0.5 μm-3 μm.

[0019] In these embodiments, the appropriate surface roughness can improve the lubrication performance of the coating and reduce friction and wear. The surface roughness of the remelted area according to the present application is relatively small, and the smaller surface roughness can avoid the accumulation of corrosive media and reduce the possibility of corrosive media invading the coating, thereby improving the corrosion resistance of the coating. And the smaller surface roughness helps to improve the flatness and finish of the coating surface.

[0020] In some embodiments, the remelted region is formed by performing a pulsed electron beam on a thermal spray layer formed of ferroferric oxide, iron nitride, iron carbide, or iron carbide nitride.

[0021] In these embodiments, by performing pulse electron beam treatment on the thermal spray coating formed of ferroferric oxide, iron nitride, iron carbide or iron carbide nitride, a remelted region with improved surface properties and enhanced bonding strength can be formed, thereby improving the corrosion resistance of the overall coating. In addition, during the pulse electron beam treatment, the energy of the pulse electron beam can be controlled to ensure that only the surface layer of the thermal spray coating is treated without affecting the substrate.

[0022] In some embodiments, the thermally sprayed region is formed by plasma spraying.

[0023] In these embodiments, the thermal spraying area is formed by utilizing the high temperature and high-speed spraying of plasma, and the obtained coating has good bonding force with the substrate and a certain density, and this method of forming the layer is more efficient and faster.

[0024] According to a second aspect of the present application, a cookware is provided, wherein the cookware comprises a cookware base and the corrosion-resistant coating provided in the above-mentioned embodiments located on the surface of the cookware base, and the remelted area serves as the surface layer of the cookware.

[0025] According to the cookware provided in the embodiment of the present application, the corrosion-resistant coating of the cookware is a ferroferric oxide layer, an iron nitride layer, an iron carbide layer or a nitride iron carbide layer. The corrosion-resistant coating itself has a certain corrosion resistance due to the characteristics of the forming material itself. The corrosion-resistant coating includes a thermal spraying area and a remelting area stacked on the outside of the thermal spraying area. The remelting area serves as the surface layer of the corrosion-resistant coating, that is, the corrosion-resistant coating includes a thermal spraying area located inside the corrosion-resistant coating and a remelting area connected to the outside of the thermal spraying area and located on the surface of the corrosion-resistant coating. The remelting area itself has improved surface hardness, smaller internal pores, good surface properties, etc., so using it as the surface layer of the corrosion-resistant coating can better resist erosion by corrosive media, has good corrosion resistance, and can extend the corrosion resistance life of the coating. The remelted area is located outside the thermal spraying area, which can also protect the thermal spraying area, reduce the risk of erosion of the thermal spraying area by corrosive media, improve the corrosion resistance and protection effect of the entire coating, and the remelted area on the surface can enhance the adhesion of the coating and reduce the risk of coating peeling or falling off. Therefore, products with this corrosion-resistant coating can obtain good and lasting corrosion resistance.

[0026] In some embodiments, the cookware substrate includes an aluminum substrate, an iron substrate, a magnesium substrate, a copper alloy substrate, an alumina substrate, a stainless steel substrate or a titanium substrate.

[0027] In these embodiments, the corrosion-resistant coating can be located on various types of cookware substrates, and the substrates have a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or other features and aspects of the present invention will become clear and easily understood through the description of the embodiments in conjunction with the accompanying drawings.

[0029] Figure 1 A schematic structural diagram of a cooker according to an embodiment of the present application is shown;

[0030] Figure 2 A schematic structural diagram of a coating of a cookware according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0031] The specific implementation methods of the present application are described in detail below. Although some embodiments have been shown and described, those skilled in the art should understand that these embodiments can be modified and improved without departing from the principles and spirit of the present application whose scope is defined by the claims and their equivalents.

[0032] Amorphous alloy, also known as metallic glass, is a special alloy that has a disordered atomic structure similar to glass at room temperature. In the prior art, an amorphous alloy coating can be formed by using an amorphous alloy material. By partially remelting the amorphous alloy coating, the pores on the surface of the amorphous alloy coating can be reduced or closed, thereby achieving the effect of isolating the corrosive medium. In this scheme, the remelting of the amorphous alloy coating requires precise control of parameter conditions (for example, controlling temperature, time, single spraying thickness), etc., to ensure that the pores on the coating surface are effectively closed while also ensuring that the coating has sufficient amorphous structure. If handled improperly, remelting will cause excessive crystallization of the thermal spray coating, which will reduce the volume proportion of the amorphous phase of the final coating, that is, the amorphous structure that exerts corrosion resistance will be destroyed, thereby affecting the corrosion resistance and mechanical properties of the material. In addition, complete closure of the pores is an ideal state, while reduced pores are normal. In this case, the corrosive medium can still reach between the amorphous alloy material forming the pot coating and the pot substrate, so there will be a potential difference between the two, so there will be galvanic corrosion between the coating and the pot substrate. The above two points will cause the corrosion resistance of the cookware coating to decay rapidly. In addition, precise parameter conditions will increase the difficulty of manufacturing cookware accordingly. Moreover, the thermal spray coating formed by amorphous alloy materials will have extremely high surface roughness due to the properties of the amorphous alloy materials themselves. Therefore, the amorphous alloy coating formed by thermal spraying cannot be directly remelted, and a sanding step is required in advance. Only in this way can it be ensured that the surface of the cookware obtained by subsequent remelting has good corrosion resistance. This also means the importance of sanding the thermal spray coating in the step of manufacturing the cookware coating. If sanding is not performed, the surface roughness of the cookware coating is high and there will be more defects, such as pits, cracks and scratches. These defects are easy to become the accumulation of corrosive media and the embedding points of abrasive particles, thereby accelerating the wear and corrosion process. In addition, there are many peaks and valleys on the rough surface, which makes the contact area large and easy to be worn by shovels.

[0033] The inventor found that by thermally spraying a specific ceramic material to form a thermal spray coating, and then remelting the surface of the thermal spray coating to form the surface of the thermal spray coating into a remelting area, a cookware is manufactured, wherein the remelting area is the surface of the cookware, and has a contact surface for cooking food. The remelting area itself has improved surface hardness, smaller internal pores, and good surface properties, etc. Therefore, using it as the surface of the corrosion-resistant coating can better resist the erosion of corrosive media, has good corrosion resistance, and can extend the corrosion life of the coating. In addition, the surface roughness of the remelting area is suitable, and it can be directly used as the surface of the cookware (the surface refers to the area corresponding to the preset depth inward on the surface of the inner side of the cookware that contacts the food), so the subsequent sanding step can be omitted. According to the method for manufacturing cookware of the present application, there is no need to accurately control the remelting process, and it can achieve better corrosion resistance than the technical solution of remelting the amorphous alloy coating, and the manufacturing difficulty is greatly reduced. In addition, the surface of the cookware has a suitable roughness, which has the advantages of reducing friction noise during cooking, ensuring that food does not stick, and easy cleaning, thereby providing a good user experience.

[0034] According to a first aspect of the present application, a method for manufacturing cookware is provided, wherein the method for manufacturing cookware includes forming a thermal spray coating on a cookware substrate by thermal spraying a ceramic material, and remelting the surface layer of the thermal spray coating to form a remelted area, thereby manufacturing the cookware, wherein the remelted area serves as the surface layer of the cookware, and wherein the ceramic material includes at least one of ferrosoferric oxide, iron nitride, iron carbide and iron carbide nitrogen.

[0035] According to the method for manufacturing cookware provided in an embodiment of the present application, a thermal spray coating is formed by thermal spraying a specific ceramic material, and then the surface layer of the thermal spray coating is remelted to form the surface layer of the thermal spray coating into a remelted area, wherein the remelted area itself has improved surface hardness, smaller internal pores, and good surface properties, etc., and therefore, using it as a contact surface with cooked food can better resist erosion by corrosive media, has good corrosion resistance, and can extend the corrosion resistance life of the coating.

[0036] In the embodiment of the present application, the formed pot includes a pot substrate and a corrosion-resistant coating formed on the surface of the pot substrate, the corrosion-resistant coating is a ferroferric oxide layer, an iron nitride layer, an iron carbide layer or a nitride iron carbide layer, the corrosion-resistant coating includes a thermal spraying area and a remelting area stacked outside the thermal spraying area, the remelting area serves as the surface layer of the corrosion-resistant coating, that is, the corrosion-resistant coating includes an internal thermal spraying area and a remelting area located on the surface. Among them, the remelting area serves as the surface layer of the pot.

[0037] In these embodiments, the remelted area is located on the outside, which can also protect the thermal spraying area, reduce the risk of erosion of the thermal spraying area by corrosive media, improve the corrosion resistance and protective effect of the entire coating, and the remelted area on the surface can enhance the adhesion of the coating and reduce the risk of peeling or falling off of the coating. Therefore, products with this corrosion-resistant coating can obtain good and lasting corrosion resistance.

[0038] In an embodiment of the present application, a local area of ​​the thermal spray coating can be remelted. As an example, the surface area of ​​the thermal spray coating can be remelted. The local remelting treatment of the thermal spray coating can avoid the increase of brittleness and thermal stress due to the film layer being too dense, and the overall performance of the pot coating can be guaranteed. In this way, the quality of the pot coating can be further improved to meet the user's use needs. In this case, the formed pot includes a pot substrate and a corrosion-resistant coating located on the surface of the pot substrate, wherein the corrosion-resistant coating includes a thermal spraying area and a remelting area stacked outside the thermal spraying area, and the remelting area serves as the surface layer of the corrosion-resistant coating, that is, the corrosion-resistant coating includes a thermal spraying area inside the corrosion-resistant coating and a remelting area connected to the outside of the thermal spraying area and on the surface of the corrosion-resistant coating. Among them, the thermal spraying area located inside the corrosion-resistant coating is the remaining thermal spraying layer, and the remaining thermal spraying layer is the thermal spraying layer of the part that has not been remelted, or the internal area of ​​the thermal spraying layer before the remelting treatment, which still retains the porous structure, and the porous structure can play a shock-absorbing role, so that the impact energy of the pot during use can be buffered, and the stress can be dispersed, thereby reducing the possibility of stress concentration, reducing the risk of damage to the coating and the substrate (for example, cracks, peeling and wear, etc.), and increasing the durability and performance stability of the pot. The remelting area located on the surface of the corrosion-resistant coating is the thermal spraying layer of the part that has been remelted. In this area, this part of the thermal spraying layer has been remelted, so that it is melted to a certain extent and formed into a denser structure. The existence of the remelting area can further improve the compactness and corrosion resistance of the corrosion-resistant coating. As above, the structure of the corrosion-resistant coating combines the thermal spraying area and the remelting area so that the pot can take into account both corrosion resistance and shock absorption.

[0039] It should be noted that the “thermal spray coating” and “thermal spray area” described in the present application are both layers formed by thermal spraying, and the distinction here is only made in terminology to distinguish the layers at different stages of cookware manufacturing.

[0040] Hereinafter, the method for manufacturing a cookware according to the present application will be described in detail.

[0041] Preparing the cookware base

[0042] In the prior art, chemical nitriding and high-temperature oxidation anti-corrosion methods have certain limitations on the selection of substrates and are usually only applicable to iron-based substrates, but not to aluminum-based substrates, titanium-based substrates, etc.

[0043] According to the present application, the pot substrate can adopt the substrate for manufacturing pots in the prior art. In an embodiment, the pot substrate may include an aluminum substrate, an iron substrate, a magnesium substrate, a copper alloy substrate, an aluminum oxide substrate, a stainless steel substrate, a titanium substrate, and a composite substrate formed by the above substrates. Among them, the composite substrate is a structure in which multiple substrates are stacked, for example, it may include a titanium-aluminum-stainless steel three-layer composite substrate. It should be noted that in the case where the pot substrate is an aluminum substrate, a magnesium substrate, an iron substrate, and a composite substrate formed by at least two metals of aluminum, magnesium, and iron, since aluminum, magnesium, and iron are all materials that are easily oxidized, when the pot substrate includes a surface formed by aluminum, magnesium, or iron, corrosion will easily occur, which limits the materials for manufacturing the pot.

[0044] To this end, the method for manufacturing a cookware according to the present application includes remelting a thermal spray coating formed of a ceramic material. In this way, after the remelting treatment, the surface layer of the thermal spray coating can be changed into a denser structural layer than its interior. In this case, the pores in the interior and the surface layer are blocked, so that the corrosive medium is not easy to penetrate into the cookware substrate area, thereby ensuring the corrosion resistance and bonding strength of the cookware as a whole. In this case, the corrosive medium during cooking is not easy to contact the substrate, which can ensure a longer corrosion resistance life. In addition, the method for manufacturing the cookware can also be free from special restrictions on the type of substrate, so the method according to the present application can be suitable for more substrates, thereby expanding the range of substrates that can be adapted to cookware manufacturing, and has good versatility.

[0045] In addition, when the cookware base is a composite matrix formed by at least two metals among an aluminum base, a magnesium base and an iron base, the weight of the formed cookware can be reduced to a great extent because it includes relatively light aluminum and magnesium, which is extremely beneficial for the elderly and the like with less strength.

[0046] According to the present application, after selecting the cookware substrate, the method for manufacturing the cookware further includes performing alkaline washing, degreasing, and drying operations on the surface of the cookware substrate to avoid affecting the bonding strength between the subsequent coating and the cookware substrate.

[0047] Prepare ceramic materials

[0048] The causes of corrosion include rust and galvanic corrosion. According to the present application, ceramics are usually non-metallic materials. Due to their own characteristics, the ceramic material and the cookware substrate lack the necessary conditions for galvanic corrosion (for example, there is no good electron and ion conduction between them, which is not conducive to the formation of a potential difference between the ceramic and the metal substrate). Therefore, the layer formed by thermal spraying of the ceramic material will not undergo galvanic corrosion with the metal substrate, thereby further ensuring the corrosion resistance of the obtained cookware.

[0049] It should be noted that the ceramic material of the present application includes at least one of ferroferric oxide, iron nitride, iron carbide and nitrided iron carbide, which can be obtained commercially and is a pure ceramic material, and does not contain metal powder or alloy powder. This is because the introduction of metal powder will easily cause a potential difference between the formed layer and the cookware substrate, and there is a possibility of galvanic cell corrosion, which will accelerate the corrosion and shedding of the cookware coating. It should be noted that when the ceramic material includes a mixture of two or more of ferroferric oxide, iron nitride, iron carbide and nitrided iron carbide, the present application does not deliberately limit the mixing ratio of the mixture.

[0050] In some embodiments, the ceramic material is granular, and the ceramic material includes at least one of ferroferric oxide, iron nitride, iron carbide and nitrided iron carbide. These materials have good corrosion resistance and are black, so a thermal spray coating with certain corrosion resistance and antifouling properties can be obtained. Specifically, ferroferric oxide can easily form a ferroferric oxide film layer that can effectively isolate moisture and oxygen when using the pot, preventing the pot substrate from contacting these corrosive media, thereby improving the corrosion resistance of the pot. Iron nitride can easily form an iron nitride layer, which can provide higher hardness and good wear resistance and corrosion resistance. After treatment under certain conditions, this coating can also improve the wear resistance of the pot. Iron carbide usually appears in the microstructure of steel and can improve the hardness and strength of the material. Therefore, in the pot, an appropriate amount of carbide is conducive to improving corrosion resistance and has certain heat resistance. In addition, nitrided iron carbide can combine the above advantages of carbides and nitrides to provide additional hardness and stability. Therefore, the thermal spray coating formed of the above materials can itself have certain durability and corrosion resistance.

[0051] In some embodiments of the present application, when the ceramic material is granular, the particle size of the ceramic material is in the range of 200-300 mesh. If the particle size of the ceramic material is greater than 200 mesh, the pores of the thermal spray coating formed may be too large and the surface may be rougher due to the excessively large material particles, thereby increasing the time for the subsequent remelting process and weakening the corrosion resistance of the formed pot. In addition, if the particles are too large, the particles will rebound after hitting the surface of the substrate, thereby reducing the deposition efficiency of the material and wasting raw materials. In addition, if the material particles are too large, the spraying construction is poor, and the film thickness of the thermal spray coating is easily uneven. If the particle size of the corrosion-resistant material is less than 300 mesh, the construction difficulties may occur during the plasma spraying process due to the small particles (for example, the powder is easy to agglomerate, and the powder delivery is uneven due to the poor fluidity of the powder; the flying speed is insufficient due to the small powder and the light weight, which reduces the deposition efficiency and wastes the raw materials).

[0052] In some other embodiments according to the present application, when the ceramic material is in granular form, the ceramic particles exist in the form of multiple particle sizes. By selecting a powder of a combination of large and small particles as the ceramic material of the present application, a thermal spray coating in which the particles are closely packed together can be obtained, thereby reducing the porosity of the coating.

[0053] Specifically, the particle size R of the ceramic granular material has multiple distribution ranges, wherein the multiple distribution ranges include a first distribution range, a second distribution range and a third distribution range, the first distribution range is 200 mesh ≤ R < 300 mesh, the second distribution range is R> 200 mesh, and the third distribution range is R≤300 mesh, wherein, based on the total volume of the ceramic material in the mixture as 100%, the volume of the ceramic material with a particle size in the first distribution range accounts for 93%-95%, the volume of the ceramic material with a particle size in the second distribution range accounts for 1%-2%, and the volume of the ceramic material with a particle size in the third distribution range accounts for 3%-5%. It should be noted that particles in multiple distribution ranges can be obtained by grinding and screening.

[0054] Forming thermal spray coating

[0055] According to the present application, the thermal spray coating can be at least partially formed on the inner surface and / or outer surface of the cookware substrate. In other words, the thermal spray coating can cover a part or all of the surface of the cookware substrate, and the surface here can be the inner surface and / or the outer surface. The thermal spray coating is formed by thermal spraying the ceramic material provided by the embodiment of the present application, so as to have non-stick properties and improved hardness.

[0056] According to some embodiments of the present application, a ceramic material is thermally sprayed on the surface of a cookware substrate to form a thermal spray coating on the surface of the cookware substrate. During the thermal spraying process, powdered ceramic particles are heated to a molten or semi-molten state and sprayed onto the surface of the cookware substrate at an extremely high speed, and a firm thermal spray coating is formed after cooling. Thermal spraying can be performed by plasma spraying. Specifically, the ceramic material is placed in a powder feeder of a plasma spraying device, the ceramic tank is evacuated to 3Pa-5Pa, and argon gas is injected to 5×10 3 -10×10 3 Pa. Using plasma arc, the ceramic material melts and adheres to the surface of the cookware substrate to form a thermal spray coating. Among them, the plasma arc power is set to 30KW-55KW, the arc current is set to 300A-700A, the spraying distance is set to 100mm-150mm, the spraying angle is set to 60°-80°, the powder feeding speed is set to 25g / min-45g / min, the hydrogen pressure is set to 0.3MPa-0.5MPa, and the hydrogen flow rate is set to 3L / min-8L / min. Among them, the cookware substrate is preheated to 200℃-250℃ before spraying, and cooled with a 5℃-15℃ cold air gun after spraying.

[0057] According to the present application, by performing thermal spraying on the ceramic material within the above-mentioned process parameter range, a corrosion-resistant coating with a suitable thickness and a smooth surface obtained only by remelting can be formed on the surface of the substrate. The corrosion-resistant coating has properties similar to those of the ceramic material, and therefore can have excellent properties such as high hardness, thermal stability, wear resistance, and chemical corrosion resistance. In other words, the corrosion-resistant coating conceived according to the present invention can retain various properties of the ceramic material therein, and the surface layer is formed into a remelting area with a small porosity, pores, and roughness, which as the surface layer of the pot can ensure the corrosion resistance of the pot.

[0058] In the prior art, the amorphous alloy coating will cause galvanic corrosion with the cookware substrate due to the potential difference, so a thickness of 200μm-500μm is required to ensure corrosion resistance. When the thickness is thicker than the conventional thickness, the coating is easy to peel off.

[0059] According to the present application, there is no potential difference between the ceramic material and the substrate, and galvanic corrosion will not occur. In addition, the present application can adopt a thickness that is not easy to peel off, so better corrosion resistance and bonding strength can be obtained than the above. According to the present application, the thermal spray coating can have a thickness of 30μm-60μm, which can avoid the risk of detachment due to thick coating and high thermal stress to a certain extent. If the thickness of the thermal spray coating is less than 30μm, the coating is not easy to form a film and cannot completely cover the cookware substrate. If the thickness of the thermal spray coating is higher than 60μm, the thermal stress of the coating is large and it is easy to collapse.

[0060] In some embodiments, the formed thermal spray coating has a certain porosity and pore size, which makes it easier for the corrosive medium to penetrate into the substrate. As an example, the porosity of the thermal spray coating is 3-8%, and the pore size is in the range of 15μm-25μm. In addition, due to the influence of the spraying process, the surface of the thermal spray coating has a certain rough structure. As an example, the surface roughness of the thermal spray coating is 5μm-7μm. Such a rough surface will weaken the corrosion resistance and is not suitable for being directly used as the surface of the pot in contact with the food. The hardness is 1200HV-1750HV, and the durability is average. In this case, the corrosion resistance of the thermal spray coating directly used as the pot coating is extremely poor. Therefore, it is extremely necessary to perform certain treatments on the thermal spray coating.

[0061] Formation of a remelted area on the surface of the thermal spray coating

[0062] According to the present application, the surface layer of the thermal spray coating is remelted to form a remelted area, wherein the remelting process refers to melting the surface layer of the thermal spray coating that has been solidified and formed again, and then rapidly cooling it in a certain way to form a new organizational structure and properties. Through appropriate remelting treatment, defects and internal stresses in the thermal spraying process, such as pores, inclusions and cracks, etc., can be eliminated, and the grains can be refined to obtain a remelted area with a higher density, so that the surface density of the final coating (i.e., the corrosion-resistant coating to be described below) is higher. Electron beam remelting can promote better bonding between the coating and the substrate, enhance the adhesion and stability of the coating, and avoid the situation where the corrosion resistance is too poor due to the shedding of the coating. In addition, through remelting treatment, the surface properties, hardness and wear resistance of the final coating can also be improved.

[0063] In the prior art, the remelting treatment may include electron beam remelting (EBM) or laser remelting. In the current laser remelting method, the laser spot is small, the material surface reflectivity is high, the utilization rate is only 5-10%, and the processing power is too large, which is suitable for amorphous materials but not for ceramic materials. Therefore, in this application, a pulse electron beam remelting method is used to perform remelting treatment on the thermal spray coating formed by ceramic materials. The pulse electron beam has highly concentrated energy. By using the electron beam for rapid heating, a high energy density heat treatment can be provided in a very short time, so that the surface layer of the thermal spray coating is instantly melted, and then it is rapidly solidified after cooling to form a new surface area, that is, the remelting area. In this process, the pulse electron beam method can reduce the heat affected zone, thereby controlling the thermal impact during the coating treatment process, avoiding structural damage caused by excessive thermal impact, generating a large amount of thermal stress and residual stress, and the appearance of defects such as poor melting, pores and inclusions. In addition, the pulsed electron beam can instantly heat the thermal spray coating in a very short time, achieving the effect of local remelting, reducing the heat conduction and thermal impact on the substrate, which will help to apply to more types of substrates and ensure the original performance and dimensional stability of the substrate. In general, the quality of the coating can be easily controlled through electron beam remelting.

[0064] According to the present application, a more uniform microstructure can be obtained by electron beam remelting treatment, so that the coating surface of the cookware forms a more flat and uniform structure, reduces defects such as cracks and pores, and improves wear resistance. In addition, the thermal spray coating will have large internal stress during the formation process, which will also affect the corrosion resistance and mechanical properties of the cookware coating. These stresses can be released and redistributed through remelting treatment, thereby improving the performance of the cookware coating. In addition, remelting the thermal spray coating formed by a variety of ceramic materials can cause the microstructure of the coating to change, from an amorphous or crystalline state to a more stable form, which may lead to increased hardness, wear resistance and enhanced oxidation resistance. In addition, the surface layer of the thermal spray coating is remelted, and the remelted area obtained has good heat resistance, which can ensure the thermal stability of the coating.

[0065] In the present application, the remelted area itself has improved surface hardness, smaller internal pores, and good surface properties. The remelted area is used as the surface layer of the pot, that is, the surface layer of the pot has improved properties. Such a pot can resist erosion by corrosive media, thereby extending the corrosion life of the pot. In addition, the density of the surface layer and the internal pores of the pot coating (i.e., the corrosion-resistant coating to be described below) are different, which will inevitably greatly reduce the number of pores that directly pass from the outside to the pot substrate. In this way, it is possible to block external corrosive conditions from entering the pot substrate, avoid the situation where the corrosion resistance is too poor due to the shedding of the coating, and ensure the corrosion resistance of the pot as a whole. In this case, there is no need to limit the material of the pot substrate, so that the method of manufacturing the pot of the present application can be suitable for more types of pot substrates.

[0066] Traditional coatings may require a transition layer or a primer layer to improve the adhesion between the coating and the substrate. According to the present application, the substrate surface can be partially melted during the remelting process, so that the thermal spray coating and the substrate are mixed at the molecular level, strengthening their adhesion, thereby improving the overall mechanical strength of the coating. Therefore, the method for manufacturing cookware of the present application can omit the step of setting a transition layer (priming layer) and simplify the production process.

[0067] In the prior art, in the process of remelting the amorphous alloy coating, it is necessary to precisely control parameters (for example, temperature and time) to ensure the effective closure of the pores on the coating surface and to ensure that the coating still maintains a certain amorphous structure. However, according to the present application, the remelting treatment of the thermal spray coating formed by the ceramic material does not require precise control of various parameters, which can reduce the difficulty of production control to a certain extent. According to the present application, the remelting treatment can be carried out by using a pulsed electron beam. Before the pulsed electron beam treatment, only key parameters such as pulse duration, energy density and number of repetitions need to be roughly determined. These parameters can ensure that the thermal spray coating obtains sufficient energy for remelting while avoiding overheating or damage, and there is no need to precisely control various parameters. In some embodiments, the specific process parameters of the electron beam remelting process include: electron beam power of 25Kev-35Kev; energy density of 3J.cm 2 -6J.cm 2 ; Pulse duration is 1μS-3μS; vacuum degree is 1×10 -3 Pa-2×10 -3 Pa; electron beam spot size 50mm-80mm. Under the above parameters, the pulsed electron beam can make the surface layer of the thermal spray coating be treated at a suitable temperature for a certain time, for example, the temperature is roughly 2000℃-2500℃, and the time is 1μS-3μS, so as to form a remelting layer with good performance and avoid excessive remelting and influence on the substrate.

[0068] Compared with laser treatment, pulsed electron beam treatment has a lower power and is less likely to cause excessive surface remelting during treatment. Therefore, multiple treatments are required to achieve the desired purpose. However, it should be noted that the more times, the better. The number of times can be set based on the surface defects of the thermal spray coating, such as the degree of roughness. As an example, the number of repetitions of electron beam remelting in the method for manufacturing the pot according to the present application can be 10 to 20 times.

[0069] According to the present application, performing an appropriate number of electron beam remelting on the surface layer of the thermal spray coating can enhance the compactness of the surface layer, improve the grain refinement and adhesion of the surface layer. Specifically, after multiple remelting treatments, the surface layer of the thermal spray coating becomes more compact, which can prevent corrosive substances from penetrating into the interior of the remelting area, thereby improving the corrosion resistance of the coating. In addition, multiple remelting treatments can eliminate the defects of the surface layer, make the surface smoother, reduce surface flaws and unevenness, thereby improving the surface quality of the coating. In addition, multiple remelting treatments can reduce the grain size of the surface layer, make the surface layer denser, and improve the adhesion of the surface layer, improve the bonding between the surface layer and the substrate, and increase the thermal conductivity of the coating, thereby improving the heating efficiency of the pot. In summary, multiple electron beam remelting treatments help to improve the quality of the thermal spray coating and improve the performance of the pot.

[0070] According to the present application, the remelting area is formed on the surface of the thermal spray coating, wherein the surface of the thermal spray coating refers to the area corresponding to a certain thickness from the surface to the inside of the thermal spray coating, as an example, the thickness of the thermal spray coating is 30μm-60μm, and the preset value is 1 / 3-1 / 2 of the thickness of the thermal spray coating, where the influencing factors of the thickness are determined by the pulse duration, energy density and number of repetitions. As an example, the thickness can be 15μm-25μm.

[0071] According to the present application, the porosity of the remelted area is 0.3%-0.5%; the pore size is 5μm-10μm, and / or the hardness of the remelted area is 1200HV-1750HV; and / or the surface roughness of the remelted area is 0.5μm-3μm.

[0072] According to the method for manufacturing the cookware of the present application, after the remelting treatment, it is not necessary to sand the remelted area, because the remelting treatment is sufficient to improve the surface quality of the coating, so that the surface of the cookware meets the corrosion resistance requirements, and makes the surface of the cookware smoother and more uniform. In this way, the process steps can be simplified, the manufacturing cost can be reduced because the sanding step is not required, and the production efficiency can be improved.

[0073] Ceramic coatings and amorphous alloy coatings have different physical and chemical properties, and these differences lead to different requirements for their surface treatment after thermal spraying. Amorphous alloy coatings, although they generally have better wear resistance and corrosion resistance, may form irregular connections between larger particles and the coating substrate as well as tiny defects during the thermal spraying process. If sanding is not performed, these defects can easily become embedding points for abrasive particles and accumulation points for corrosive media, thereby accelerating the wear and corrosion process. In addition, the rough surface has more peaks and valleys, resulting in a large actual contact area, making the wear more severe. Therefore, sanding is extremely necessary before remelting the amorphous alloy coating, otherwise it is difficult to ensure corrosion resistance and durability.

[0074] However, the thermal spray coating formed of ceramic material has strong adhesion and good coating smoothness, so the required surface roughness and quality can be achieved without sanding after coating. Therefore, according to the method for manufacturing cookware of the present application, the thermal spray coating does not need to be sanded before the remelting process, and the corrosion resistance and durability can be ensured, so that the steps of manufacturing cookware can be shortened and the manufacturing process can be simplified.

[0075] According to the present application, by using ceramic materials with lower costs than amorphous materials, corrosion resistance equivalent to that of amorphous alloy coatings can be obtained, and steps in the manufacturing process are reduced, production efficiency is improved, and good economic benefits are achieved.

[0076] According to the present application, the remelted coating forms the final surface layer of the cookware (i.e., the corrosion-resistant coating). The surface of the surface layer can be used as the inner surface of the cookware that contacts the food during use, and the surface opposite to the inner surface is the outer surface of the cookware, where the inner surface and outer surface are generally understood by those skilled in the art.

[0077] According to a second aspect of the present application, a corrosion-resistant coating is provided, which is at least used in cookware, wherein the corrosion-resistant coating is a ferroferric oxide layer, an iron nitride layer, an iron carbide layer or a nitride iron carbide layer, and the corrosion-resistant coating includes a thermal spraying region and a remelting region stacked on the outside of the thermal spraying region, and the remelting region serves as the surface layer of the corrosion-resistant coating, that is, the corrosion-resistant coating includes the thermal spraying region located inside the corrosion-resistant coating and the remelting region connected to the outside of the thermal spraying region and located on the surface layer of the corrosion-resistant coating.

[0078] According to the corrosion-resistant coating provided in the embodiment of the present application, the corrosion-resistant coating is a ferroferric oxide layer, an iron nitride layer, an iron carbide layer or a nitride iron carbide layer. Due to the characteristics of the forming material itself, the corrosion-resistant coating itself has a certain corrosion resistance. The corrosion-resistant coating includes a thermal spraying area and a remelting area stacked on the outside of the thermal spraying area. The remelting area serves as the surface layer of the corrosion-resistant coating, that is, the corrosion-resistant coating includes a thermal spraying area located inside the corrosion-resistant coating and a remelting area connected to the outside of the thermal spraying area and located on the surface of the corrosion-resistant coating. The remelting area itself has improved surface hardness, smaller internal pores, good surface properties, etc. Therefore, using it as the surface layer of the corrosion-resistant coating can better resist erosion by corrosive media, has good corrosion resistance, and can extend the corrosion resistance life of the coating. The remelted area is located outside the thermal spraying area, which can also protect the thermal spraying area, reduce the risk of erosion of the thermal spraying area by corrosive media, improve the corrosion resistance and protection effect of the entire coating, and the remelted area on the surface can enhance the adhesion of the coating and reduce the risk of coating peeling or falling off. Therefore, products with this corrosion-resistant coating can obtain good and lasting corrosion resistance.

[0079] It should be noted that, in the present application, the thermal spray coating and the corrosion-resistant coating are products of different stages of the cookware manufacturing process, respectively. The thermal spray coating is presented during the method process, while the corrosion-resistant coating is presented in the final product.

[0080] It should be noted that in the present application, the ferroferric oxide layer, iron nitride layer, iron carbide layer or iron carbide nitride layer are layers formed by using ferroferric oxide, iron nitride, iron carbide or iron carbide nitride known in the art through existing spraying processes.

[0081] In some embodiments, the remelting area is located at the surface layer of the corrosion-resistant coating and has a preset value, and the preset value is 1 / 3-1 / 2 of the thickness of the corrosion-resistant coating.

[0082] In these embodiments, the remelted area is located at a preset value on the surface of the corrosion-resistant coating, thereby providing a longer-term corrosion protection to increase the corrosion resistance durability of the coating. In addition, the remelted area has a certain formation thickness, which can balance the corrosion resistance of the corrosion-resistant coating with other factors, such as adhesion, surface hardness, durability, etc.

[0083] In some embodiments, the thickness of the corrosion-resistant coating is 30μm-60μm, and the preset value is 15μm-25μm. In this embodiment, the preset value is 15μm-25μm, which is the thickness of the remelting area. If the thickness of the remelting area is greater than 25μm, a higher temperature and longer time are required, which may cause the ceramic layer to be overheated, resulting in overall cracking or falling off, and the strength of the remelting area will decrease, and there may be a risk of damage to the substrate (for example, the aluminum substrate melts and deforms, and the outer surface of the stainless steel substrate is severely rusted due to oxidation, etc.); if the thickness of the remelting area is less than 15μm, the rough surface formed by thermal spraying cannot be completely flattened, resulting in the final density and roughness of the surface of the pot being too high, the long-term corrosion resistance effect is poor, and it affects the later use.

[0084] In these embodiments, when the thickness of the corrosion-resistant coating is 30 μm-60 μm, the thickness of the remelted area is 15 μm-25 μm, so that the product having the corrosion-resistant coating can be ensured to have good corrosion resistance, adhesion and surface hardness.

[0085] In some embodiments, the porosity of the remelted region is 0.3%-0.5%, and the pore size is 5 μm-10 μm.

[0086] In these embodiments, the pore structure limited by such porosity and pore size is relatively dense, and corrosive media are not easy to enter, and the channel for corrosive media to contact the cookware substrate can be blocked, thereby further improving the corrosion resistance.

[0087] In some embodiments, the hardness of the remelted region is 1200 HV-1750 HV.

[0088] In these embodiments, the remelted area has improved hardness, and thus has good wear and scratch resistance, thereby extending the service life of the corrosion-resistant coating.

[0089] In some embodiments, the surface roughness of the remelted region is 0.5 μm-3 μm.

[0090] In these embodiments, the appropriate surface roughness can improve the lubrication performance of the coating and reduce friction and wear. The surface roughness of the remelted area according to the present application is relatively small, and the smaller surface roughness can avoid the accumulation of corrosive media and reduce the possibility of corrosive media invading the coating, thereby improving the corrosion resistance of the coating. And the smaller surface roughness helps to improve the flatness and finish of the coating surface.

[0091] In some embodiments, the remelted region is formed by performing a pulsed electron beam on a thermal spray layer formed of ferroferric oxide, iron nitride, iron carbide, or iron carbide nitride.

[0092] In these embodiments, the pulse electron beam treatment has the characteristics of rapid heating and cooling, and by performing pulse electron beam treatment on the thermal spray coating formed of ferroferric oxide, iron nitride, iron carbide or iron carbide nitride, a remelted area with improved surface properties and enhanced bonding strength can be formed, thereby improving the corrosion resistance of the overall coating. In addition, during the process of performing the pulse electron beam treatment, the energy of the pulse electron beam can be controlled to ensure that only the surface layer of the thermal spray coating is treated without affecting the substrate.

[0093] In some embodiments, the thermal spraying region is formed by plasma spraying, wherein the thermal spraying region may be a portion of the thermal spraying layer that has not been subjected to a remelting process.

[0094] In these embodiments, the thermal spraying area is formed by utilizing the high temperature and high-speed spraying of plasma, and the obtained coating has good bonding force with the substrate and a certain density, and this method of forming the layer is more efficient and faster.

[0095] According to the third aspect of the present application, a cookware is provided, wherein the cookware comprises a cookware substrate and the corrosion-resistant coating provided in the above-mentioned embodiments formed on the surface of the cookware substrate, wherein the corrosion-resistant coating is a ferroferric oxide layer, an iron nitride layer, an iron carbide layer or a nitride iron carbide layer, and the corrosion-resistant coating comprises a thermal spraying region and a remelting region stacked outside the thermal spraying region, and the remelting region serves as the surface layer of the corrosion-resistant coating, that is, the corrosion-resistant coating comprises an internal thermal spraying region and a remelting region located on the surface layer. The remelting region serves as the surface layer of the cookware.

[0096] In some embodiments, the cookware substrate includes an aluminum substrate, an iron substrate, a magnesium substrate, a copper alloy substrate, an alumina substrate, a stainless steel substrate or a titanium substrate, and a composite substrate formed by the above substrates.

[0097] In these embodiments, the corrosion-resistant coating can be located on various types of cookware substrates, and the substrates have a wider range of applications.

[0098] According to the present application, the cookware provided in the embodiment of the present application can be manufactured by the method for manufacturing the cookware according to the first aspect of the present application. Specifically, a thermal spray coating can be formed on the cookware substrate by thermal spraying a ceramic material, and the surface layer of the thermal spray coating is remelted to form a remelted area, thereby manufacturing the cookware, wherein the remelted area is the surface layer of the cookware, and the ceramic material includes at least one of ferroferric oxide, iron nitride, iron carbide, and iron carbide nitrogen. The coating of the prepared cookware is the corrosion-resistant coating described above.

[0099] like Figure 1 and Figure 2 As shown, the cookware includes a cookware substrate 10 and a corrosion-resistant coating 20 located on the surface of the cookware substrate 10, wherein the corrosion-resistant coating 20 includes a thermal spraying area 21 located inside and a remelting area 22 located on the surface, wherein the thermal spraying area 21 is the portion of the thermal spraying layer that has not been remelted, and can also be called the remaining thermal spraying layer, and the remelting area 22 is the surface portion of the thermal spraying layer that has been remelted. The remelting area is obtained by remelting the surface of the thermal spraying layer formed of a ceramic material, and the remelting area 22 is located on the surface of the thermal spraying layer formed of a ceramic material from the outside to the inside, and has a preset value.

[0100] Of course, the present application is not limited to this. Ceramic material may be first used to form an internal thermal spraying area on the cookware substrate, and then ceramic material may be continued to be sprayed on the thermal spraying area to form a coating, and the coating may be remelted as a whole, thereby forming a corrosion-resistant coating according to the present application, including a thermal spraying area inside the corrosion-resistant coating and a remelting area connected to the outside of the thermal spraying area and on the surface of the corrosion-resistant coating.

[0101] According to the present application, the hardness and density are improved, the anti-fouling property is better, the scratching and friction sound of food, spatulas, etc. during cooking is smaller, and the corrosion resistance is also better.

[0102] In the embodiment, the surface roughness of the remelted area is 0.5 μm-3 μm. Compared with the thermal spray coating, the roughness is significantly reduced. On the one hand, the corrosive medium is not easy to accumulate, which can improve the corrosion resistance. On the other hand, it can reduce the friction noise during the cooking process, ensure that the food is non-sticky, easy to clean, etc., so as to obtain a good user experience.

[0103] The present application will be described in detail below in conjunction with embodiments, but the protection scope of the present application is not limited to the embodiments.

[0104] Example 1

[0105] The cookware according to Example 1 was prepared by the following method.

[0106] Step S10, providing a stainless steel cookware base with a thickness of 1.8 mm, pre-treating the surface of the cookware, cleaning the surface oil of the cookware with an alkaline solvent, then cleaning with clean water and drying. Then, sandblasting the surface to roughen it. Then, preheating the cookware to 230° C. in a heating furnace.

[0107] Step S20, providing a ceramic material: providing ferrosoferric oxide with an average particle size of 200 meshes as the ceramic material.

[0108] Step S30, preparing a thermal spray coating.

[0109] Step S31, placing the outer surface of the cookware in a circulating cooling air environment, and the temperature of the cooling air is set at -10°C.

[0110] Step S32: The vacuum degree of the spraying chamber is evacuated to 3 Pa, and then argon gas is injected to 6×10 3 Pa. The ceramic material is placed in the powder feeder of the plasma spraying equipment, and the ferroferric oxide is thermally sprayed on the preheated pot surface by plasma arc starting, and a thermal spray layer with a thickness of 40μm is sprayed. Among them, the plasma arc power is set to 30Kw, the arc current is set to 700A, the spraying distance is set to 120mm, the spraying angle is set to 70°, the powder feeding speed is set to 25g / min, the hydrogen pressure is set to 0.5MPa, and the flow rate is set to 7L / min. Under the above parameters, the high-pressure plasma flame flow formed at the muzzle heats the surface of the ceramic material to melt, and then deposits it on the surface of the pot substrate to form a thermal spray layer with a thickness of 40μm on the pot substrate.

[0111] In step S40, a remelting process is performed on the thermal spray coating to form a remelting region with a preset depth on the surface layer of the thermal spray coating.

[0112] The thermal spray coating was remelted by pulse electron beam, where the setting parameters of the pulse electron beam were: electron beam power of 25Kev; electron beam energy of 3J.cm 2; Processing time is 1μS; Vacuum degree is 1*10 -3 Pa; electron beam spot size 80 mm. The thermal spray coating was treated 10 times with the same parameters and then naturally cooled to room temperature, thereby obtaining a pot with a remelted area with a thickness of 15 μm.

[0113] Example 2

[0114] The cookware of Example 2 was prepared by the same method as that of Example 1, except that the thermal spraying material of Example 1 was replaced by iron nitride.

[0115] Example 3

[0116] The cookware of Example 3 was prepared by the same method as that of Example 1, except that the thermal spraying material of Example 1 was replaced by iron carbide.

[0117] Example 4

[0118] The cookware of Example 4 was prepared by the same method as that of Example 1, except that the thermal spraying material of Example 1 was replaced by iron carbonitride.

[0119] Example 5

[0120] The cookware of Example 5 is prepared by the same method as that of Example 1, except that the thermal spraying material of Example 1 is replaced by a mixture of ferrosoferric oxide and iron carbonitride in a mass ratio of 1:1.

[0121] Example 6

[0122] The cookware of Example 6 is prepared by the same method as that of Example 1, except that the thermal spraying material of Example 1 is replaced by a mixture of ferrosoferric oxide and iron carbide in a mass ratio of 1:1.

[0123] Example 7

[0124] The cookware of Example 7 was prepared in the same manner as in Example 1, except that the aluminum substrate of Example 1 was replaced by an iron substrate.

[0125] Example 8

[0126] The cookware of Example 8 was prepared in the same manner as in Example 1, except that the aluminum substrate of Example 1 was replaced with an alumina substrate.

[0127] Example 9

[0128] The cookware of Example 9 was prepared by the same method as that of Example 1, except that the aluminum substrate of Example 1 was replaced by an iron alloy substrate.

[0129] Example 10

[0130] The cookware of Example 10 was prepared in the same manner as in Example 1, except that the aluminum substrate of Example 1 was replaced by a copper substrate.

[0131] Embodiment 11

[0132] The cookware of Example 11 was prepared by the same method as that of Example 1, except that the average particle size of the ferrosoferric oxide in Example 1 was changed from 200 mesh to 300 mesh.

[0133] Example 12

[0134] The cookware of Example 12 is prepared by the same method as Example 1, except that the average particle size of ferrosoferric oxide of 200 mesh is replaced by a multi-particle size form (that is, the first distribution interval is 200 mesh ≤ R < 300 mesh, the second distribution interval is R > 200 mesh, and the third distribution interval is R ≤ 300 mesh, wherein, based on the total volume of the ceramic material in the mixture as 100%, the volume of the ceramic material with a particle size in the first distribution interval accounts for 94%, the volume of the ceramic material with a particle size in the second distribution interval accounts for 2%, and the volume of the ceramic material with a particle size in the third distribution interval accounts for 4%).

[0135] Comparative Example 1

[0136] In addition to replacing the thermal spray material of Example 1 with Fe 80 -Cr5-Mo6-B4-Si5, the cookware of Comparative Example 1 was prepared by the same method as that of Example 1.

[0137] Comparative Example 2

[0138] In addition to replacing the thermal spray material of Example 1 with Zr 60 -Cr 20 -Nb 13 -Ni5-Hf2, the cookware of Comparative Example 2 was prepared by the same method as that of Example 1.

[0139] Comparative Example 3

[0140] The cookware of Comparative Example 3 was prepared in the same manner as in Example 1, except that the thermal spray coating of Example 1 was not subjected to the remelting treatment (ie, step S40 was not included).

[0141] Comparative Example 4

[0142] The cookware of Comparative Example 4 was prepared by the same method as that of Example 2, except that the thermal spray coating of Example 2 was not subjected to the remelting treatment (ie, step S40 was not included).

[0143] Comparative Example 5

[0144] The cookware of Comparative Example 5 was prepared by the same method as that of Example 3, except that the thermal spray coating of Example 3 was not subjected to the remelting treatment (ie, step S40 was not included).

[0145] Comparative Example 6

[0146] The cookware of Comparative Example 6 was prepared in the same manner as in Example 4, except that the thermal spray coating of Example 4 was not subjected to the remelting treatment (ie, step S40 was not included).

[0147] Comparative Example 7

[0148] The cookware of Comparative Example 7 was prepared by the same method as that of Example 5, except that the thermal spray coating of Example 5 was not subjected to the remelting treatment (ie, step S40 was not included).

[0149] Comparative Example 8

[0150] The cookware of Comparative Example 8 was prepared by the same method as that of Example 6, except that the thermal spray coating of Example 6 was not subjected to the remelting treatment (ie, step S40 was not included).

[0151] Comparative Example 9

[0152] The cookware of Comparative Example 9 is prepared by the same method as that of Example 1, except that the thermal spray coating of Example 1 is not subjected to the remelting treatment step (i.e., step S40 is not included) and the thermal spray coating of Example 1 is filled with a sealant (the sealant is silica sol).

[0153] Comparative Example 10

[0154] The cookware of Comparative Example 10 is prepared by the same method as that of Example 2, except that the thermal spray coating of Example 2 is not subjected to the remelting treatment step (i.e., step S40 is not included) and the thermal spray coating of Example 2 is filled with a sealant (the sealant is silica sol).

[0155] Comparative Example 11

[0156] (1) Preparation of amorphous alloy powder

[0157] The five metal materials of Fe, Cr, Mo, B and Si are mixed according to the atomic percentage content in the alloy chemical formula Fe80-Cr5-Mo6-B4-Si5, and the above alloy raw materials are smelted into iron-based molten alloy liquid in a smelting furnace. The iron-based molten alloy liquid is sprayed onto a high-speed rotating copper quenching plate. Under the action of centrifugal force, the iron-based molten alloy liquid is atomized and solidified into fine particles that spread around. Inert gas is sprayed through gas nozzles installed around the quenching plate to accelerate the cooling of the fine particles to form iron-based amorphous alloy powder.

[0158] (2) Preparation of amorphous alloy coating

[0159] Step (a): Pre-treat the surface of the cookware

[0160] Use alkaline solvent to clean the oil stains on the surface of the pot, then rinse with clean water and dry. Then, sandblast the surface to roughen it.

[0161] Step (b): Preheat the pot

[0162] Preheat the pot to 230°C in a heating furnace.

[0163] Step (c): Forming an amorphous alloy coating

[0164] The vacuum degree of the spraying chamber was evacuated to 3Pa, and then argon gas was injected to 6×103Pa. Using plasma arc, the iron-based amorphous alloy powder was thermally sprayed on the preheated pot surface six times, with a spraying thickness of 50μm each time, to form an amorphous alloy coating with a thickness of 200μm. Among them, the plasma arc power was set to 30Kw, the arc current was set to 700A, the spraying distance was set to 120mm, the spraying angle was set to 70°, the powder feeding speed was set to 25g / min, the hydrogen pressure was set to 0.5MPa, and the flow rate was set to 7L / min.

[0165] Process (d): Sanding

[0166] The formed amorphous alloy coating was naturally cooled to room temperature, and the surface of the amorphous alloy coating was sanded with 120-grit sandpaper. The sanding process was terminated after the surface roughness Ra of the amorphous alloy coating reached 1 μm to 2 μm through a roughness meter.

[0167] Surface remelting

[0168] The surface layer of the amorphous alloy coating is remelted by irradiating the surface layer of the amorphous alloy coating with a laser beam, thereby forming a remelted area with a thickness of about 15 μm on the surface of the amorphous alloy coating.

[0169] Thus, the cookware of this comparative example 11 is finally obtained.

[0170] Comparative Example 12

[0171] The cookware of Comparative Example 12 was manufactured in the same manner as Comparative Example 11, except that step (d) of Comparative Example 11 was not performed.

[0172] Comparative Example 13

[0173] The cookware of Comparative Example 13 was manufactured in the same manner as Comparative Example 11, except that an amorphous alloy coating with a thickness of 200 μm was formed at one time in step (c) of Comparative Example 11.

[0174] Table 1 Parameters of the embodiments and comparative examples of the present application

[0175]

[0176]

[0177] Performance index test

[0178] (1) The coatings of the cookware of Examples 1-12 and Comparative Examples 1-13 were subjected to performance tests, and the test methods were as follows:

[0179] 1. Porosity measurement

[0180] The porosity of the sample is measured by microscopic measurement. Specifically, a metallographic microscope with a certain magnification is used to directly observe the surface pores of the sample or to observe the pores of the sample by sequentially taking parallel cross sections, and the porosity is calculated. Among them, the porosity is the data calculated and measured according to (1-density after thermal spraying / density of raw materials) × 100%.

[0181] Here, the samples were selected from different areas of the surface coating of the cookware of the embodiments and comparative examples.

[0182] As for the porosity, it is desirable that the sample has a porosity of not more than 20%.

[0183] 2. Thermal shock test method

[0184] Heat the coating of the cookware to 450℃ with an open flame and then quickly cool it in cold water at room temperature (23+ / -5). Observe whether the surface quality of the product has changes such as peeling and cracking, and record the corresponding number of times as thermal shock test data. The higher the data, the better the thermal shock performance, and vice versa.

[0185] 3. Binding strength test method

[0186] Measured according to HB 5476 method: a test specimen of specific size was made according to the standard requirements and fixed on a tensile testing machine. The specimen was stretched at a slow speed of 2 mm / min until the thermal spray coating broke, and the bonding strength data between the film layer and the substrate was recorded.

[0187] 4. Corrosion resistance test and evaluation standards

[0188] Adopt Supor's internal control standard: 5% salt spray for more than 24 hours without rust. Specifically, according to "6.17 Corrosion Resistance Test Method" in "GBT 32432-2015 Household Steel Cookware", 5% salt water prepared with distilled water is put into the cookware with samples formed on its inner surface and boiled, and kept slightly boiling, and the time it takes for rust to appear in the pot is recorded. This time is the result of the corrosion resistance test and the basis for evaluation. Here, the sample refers to the coating of the cookware of the embodiment and the comparative example.

[0189] For the corrosion resistance test, according to the project expectation, the corrosion resistance is not less than 8h.

[0190] Table 2 Performance index test data of the embodiments of the present application and the comparative examples

[0191]

[0192] In summary, the present application forms a thermal spray coating by thermal spraying a specific ceramic material, and then remelts the surface of the thermal spray coating to form the surface of the thermal spray coating into a remelting area, thereby manufacturing a pot, wherein the remelting area is the surface of the pot, and has a contact surface for cooking food. The remelting area itself has improved surface hardness, smaller internal pores, and good surface properties, etc. Therefore, using it as the surface of the corrosion-resistant coating can better resist the erosion of corrosive media, has good corrosion resistance, and can extend the corrosion life of the coating. In addition, the surface roughness of the remelting area is appropriate, and it can be directly used as the surface of the pot (the surface refers to the area corresponding to the preset depth inward on the surface of the inner side of the pot that contacts the food), so the subsequent sanding step can be omitted. According to the method for manufacturing pots of the present application, there is no need to accurately control the remelting process, and it can achieve better corrosion resistance than the technical solution of remelting the amorphous alloy coating, and the manufacturing difficulty is greatly reduced. In addition, the appropriate roughness of the cookware surface can reduce friction noise during cooking, ensure that food does not stick, and is easy to clean, thus providing a good user experience.

[0193] Although the embodiments of the present application have been described in detail above, those skilled in the art may make various modifications and variations to the embodiments of the present application without departing from the spirit and scope of the present application. However, it should be understood that, in the opinion of those skilled in the art, these modifications and variations will still fall within the spirit and scope of the embodiments of the present application defined by the claims.

Claims

1. A corrosion-resistant coating, characterized in that: The corrosion-resistant coating is a ferroferric oxide layer, an iron nitride layer, an iron carbide layer or an iron carbide nitride layer. The corrosion-resistant coating includes a thermal spraying area and a remelting area stacked outside the thermal spraying area. The remelting area serves as the surface layer of the corrosion-resistant coating.

2. The corrosion-resistant coating according to claim 1, characterized in that: The remelting area is formed at an area corresponding to a preset value inward from the surface of the corrosion-resistant coating, and the preset value is 1 / 3-1 / 2 of the thickness of the corrosion-resistant coating.

3. The corrosion-resistant coating according to claim 2, characterized in that: The thickness of the corrosion-resistant coating is 30 μm-60 μm, and / or the preset value is 15 μm-25 μm.

4. The corrosion-resistant coating according to claim 1, characterized in that: The porosity of the remelted region is 0.3%-0.5%, and the pore size is 5 μm-10 μm.

5. The corrosion-resistant coating according to claim 1, characterized in that: The hardness of the remelted area is 1200 HV-1750 HV.

6. The corrosion-resistant coating according to claim 1, characterized in that: The surface roughness of the remelted area is 0.5 μm-3 μm.

7. The corrosion-resistant coating according to claim 1, characterized in that: The remelted region is formed by performing a pulse electron beam on a thermal spray layer formed of ferroferric oxide, iron nitride, iron carbide or iron carbide nitride.

8. The corrosion-resistant coating according to claim 1, characterized in that: The thermal spraying region is formed by plasma spraying.

9. A cookware, characterized in that: The cookware comprises a cookware substrate and a corrosion-resistant coating according to any one of claims 1 to 8 located on the surface of the cookware substrate, and the remelted area serves as the surface layer of the cookware.

10. The cookware according to claim 9, characterized in that: The cookware substrate includes an aluminum substrate, an iron substrate, a magnesium substrate, a copper alloy substrate, an aluminum oxide substrate, a stainless steel substrate or a titanium substrate.

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