Nano superhard non-stick inner container with zero coating and manufacturing method of nano superhard non-stick inner container

Abstract

The invention discloses a zero-coating nanometer superhard non-stick inner container and a manufacturing method thereof. A preparation method of the zero-coating nanometer superhard non-stick inner container comprises the following steps that high-energy shot blasting treatment is conducted on a stainless steel inner container, then acid liquid etching treatment is conducted, and finally low-temperature heat treatment is conducted. Compared with similar products, the prepared zero-coating nanometer superhard non-stick inner container has the following remarkable advantages that the zero coating is really realized, and the use of a chemical coating is avoided; compared with a common stainless steel inner container, the surface hardness is 2.5 times of the original surface hardness; wear resistance is higher, and iron brush cleaning can be achieved; compared with a common stainless steel inner container, the corrosion resistance is improved by two times; compared with a common stainless steel inner container, the non-stick performance is better, and cleaning is easier; and compared with titanium alloy, carburization, ion diffusion coating and other schemes, the cost is low, and popularization is easy.

Description

Technical Field

[0001] The invention relates to the field of non-stick coatings, and in particular to a 0-coating nano super-hard non-stick liner and a manufacturing method thereof. Background Art

[0002] Existing electric rice cookers generally heat the rice in the inner pot by heating the inner pot, but the rice will gelatinize during the cooking process and easily stick to the inner pot. In order to prevent the rice from sticking to the inner pot when it is gelatinized, the inner pot of the rice cooker is usually sprayed with a non-stick coating. However, due to problems with existing coating technology, the coating is prone to fall off during long-term use, posing a potential threat to health problems. The existing so-called "0 coating" non-stick inner pot basically achieves the non-stick effect by constructing a concave-convex groove structure + PVD coating such as silica on the surface, and the coating is still inevitably used. If a metal inner pot with a true 0 coating is used, such as food-grade 304 or 316 stainless steel, the non-stick performance is greatly reduced. How to achieve a true 0 coating while achieving good non-stick properties, hardness, wear resistance, corrosion resistance and other properties has always been expected by the majority of users and the industry. Summary of the invention

[0003] In view of the problem that the existing 0-coating non-stick pan liner has insufficient anti-stick ability, the present invention provides a new 0-coating liner and a manufacturing method thereof, which forms a non-wetting structure mainly composed of micron-scale pits on the surface of the liner through high-energy shot peening and a certain etching process, thereby having a good non-stick effect.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] The first aspect of the present invention provides a method for preparing a 0-coating nano-superhard non-stick liner, comprising the following steps: high-energy shot peening treatment of the stainless steel liner, acidic liquid etching treatment after the treatment, and finally low-temperature heat treatment.

[0006] In the present invention, the advantages of high-energy shot peening and etching for preparing zero-coating non-stick liner are: liner of any shape can be processed, the equipment is simple to operate, the cost is low, and the processing efficiency is high. The size of the surface pits and the degree of hardening can be controlled by controlling the parameters such as the shot peening particle size and the shot peening time. The size and depth of the micron pits can be controlled by controlling the etching solution formula and its etching time. At the same time, high-energy shot peening can make the edge of the micron pit have good wear resistance. The combination of the two can form a wear-resistant, easy-to-clean, and durable non-stick zero-coating non-stick liner.

[0007] Preferably, the high-energy shot peening process includes one of pneumatic shot peening, ultrasonic shot peening, laser shot peening, high-pressure water shot peening, needle shot peening, and surface mechanical grinding.

[0008] Preferably, the material of the pellets used in the high-energy shot peening treatment is selected from metal, ceramic or resin.

[0009] Preferably, the diameter of the pellets treated by high-energy shot peening is 0.1-5 mm.

[0010] Preferably, the high-energy shot peening treatment is performed for 2-8 minutes.

[0011] Preferably, the etching solution used in the etching process is an acidic FeCl3 solution.

[0012] Further preferably, the etching solution contains 150-300g FeCl3, 45-65mL hydrogen peroxide, and 0-65mL hydrochloric acid per 1L. The hydrogen peroxide described in the present invention is a commercially available hydrogen peroxide agent (content: 30%), and the hydrochloric acid is a commercially available hydrochloric acid agent (content: 36.5%). The etching solution may also be added with sulfuric acid, nitric acid, etc. for acidity adjustment. The pH of the etching solution described in the present invention is less than 1.

[0013] Preferably, the temperature of the etching process is 20-80°C.

[0014] Preferably, the etching process takes 20-100 minutes.

[0015] Preferably, the treatment temperature of the low temperature heat treatment is 100-550°C.

[0016] Preferably, the low-temperature heat treatment has a treatment time of 10-60 min.

[0017] A second aspect of the present invention provides a 0-coating nano-superhard non-stick liner, which is prepared by the preparation method of the 0-coating nano-superhard non-stick liner.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] Compared with similar products, the 0-coating nano-superhard non-stick liner prepared by the present invention has the following significant advantages: truly achieving 0 coating and eliminating the use of chemical coating; compared with ordinary stainless steel liner, the surface hardness is 2.5 times the original; higher wear resistance, can be cleaned with an iron brush; compared with ordinary stainless steel liner, the corrosion resistance is improved by 2 times; compared with ordinary stainless steel liner, the non-stick property is better and easier to clean; compared with titanium alloy, carburizing and ion plating and other solutions, it has low cost and is easy to promote.

[0020] Based on high-energy shot peening technology, through martensite strengthening, fine grain strengthening and gradient structuring, the hardness, corrosion resistance and wear resistance can be improved simultaneously. The surface strengthening depth of high-energy shot peening is not less than 0.8mm, which is significantly different from the existing technology that only uses shot peening to remove rust and oxide film on the surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1It is a physical diagram of the embodiment;

[0022] Figure 2 The scanning electron microscope image of the cross section of the stainless steel inner tank after shot peening and the statistics of the surface grain size in the embodiment;

[0023] Figure 3 is a phase composition distribution diagram of an embodiment;

[0024] Figure 4 is a hardness-depth curve;

[0025] Figure 5 is the wetting angle variation diagram;

[0026] Figure 6 This is a comparison chart of non-stick test results (tested according to national standard GB / T32095.2-2015). DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention are further described below. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0029] Example 1

[0030] This embodiment provides a method for manufacturing a 0-coating nano-superhard non-stick liner. The liner used in the embodiment is a finished 304 stainless steel liner, which specifically includes the following steps:

[0031] (1) High-energy shot peening technology is used to strengthen the surface of the inner tank (the purpose of high-energy shot peening is different from the previous low-energy shot peening functions such as degreasing and descaling. Its main purpose is to achieve significant surface strengthening with a strengthening depth of not less than 0.8 mm and to construct a millimeter-level convex-concave structure). The shot medium is stainless steel, the shot diameter is 2 mm, and the shot peening time is 5 minutes. A millimeter-level concave-convex structure is constructed on the inner surface of the inner tank, and nano-sizing and martensitic phase transformation are induced on the surface to achieve significant surface strengthening. The surface strengthening depth is 1.2 mm. Figure 1 The prepared 0 coating nano super-hard non-stick pan liner is shown in the figure (right), and is compared with the ordinary 304 liner (left). The surface microstructure of the prepared 304 stainless steel liner is shown in Figure 2-3 , Figure 2 The left picture is a scanning electron microscope picture of the cross section after shot peening, and the right picture is a statistical picture of the grain size after shot peening. Figure 2 It can be seen that the surface grains of the 0-coating nano-superhard non-stick pan are refined to less than 100nm, with an average size of 79nm. Figure 3 is the cross-sectional diagram of the phase composition after shot peening. Figure 3 It can be seen that a large amount of martensite is generated on the surface of the 0-coating nano-ultra-hard non-stick pan, which will significantly strengthen the non-stick pan inner pot.

[0032] The hardness-depth curve from the surface to the core of the non-stick pan after shot peening is as follows Figure 4 shown.

[0033] (2) Etching and cleaning. The etching solution formula is FeCl3160 g / L, hydrochloric acid 55 ml / L, sulfuric acid 25 ml / L, hydrogen peroxide 55 ml / L (the reagents are selected as the conventional laboratory concentrations sold on the market), and the etching is carried out at room temperature for 45 minutes. The purpose of etching is to construct a finer micro-nano structure on the millimeter-level pit structure, increase the wetting angle, and further improve the non-stick property. Use running water to clean the surface etching solution, followed by ultrasonic cleaning with anhydrous ethanol. After cleaning, dry and place for use.

[0034] (3) Low temperature heat treatment. Low temperature heat treatment is carried out in a heat treatment furnace at a temperature of 350°C for 30 minutes. The purpose of low temperature sintering is to form a layer of oxide on the etched surface, further improving the stability and hydrophobic effect of the etched surface.

[0035] The 304 stainless steel non-stick pan treated by the above steps was tested for wetting angle. The results are as follows: Figure 5 Compared with the ordinary 304 inner pot, the nano super-hard non-stick pot inner pot has achieved a transformation from hydrophilic to hydrophobic.

[0036] The 304 stainless steel non-stick pan treated by the above steps was tested for cooking rice. The test results are as follows: Figure 6 As shown, Figure 6 This is the test result based on the national standard GB / T32095.2-2015. It can be seen that this solution achieves good non-stick properties. Compared with ordinary 304 liners, the non-stick properties are greatly improved, approaching or even reaching the national standard II non-stick level.

[0037] The high-energy shot peening technology used in this embodiment is pneumatic shot peening technology, but the technologies that can be used include but are not limited to ultrasonic shot peening technology, laser shot peening, needle shot peening technology, surface mechanical grinding, etc., and the shot particles used include metal, ceramic, resin and other types.

[0038] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the protection scope of the present invention.

Claims

1. A method for preparing a 0-coating nano super-hard non-stick liner, characterized in that: The following steps are involved: The stainless steel liner is subjected to high-energy shot peening treatment, followed by acid liquid etching treatment, and finally low-temperature heat treatment.

2. The method for preparing the 0-coated nano superhard non-stick liner according to claim 1, characterized in that: The high-energy shot peening process includes one of pneumatic shot peening, ultrasonic shot peening, laser shot peening, high-pressure water shot peening, needle shot peening, and surface mechanical grinding.

3. The method for preparing the 0-coated nano superhard non-stick liner according to claim 1, characterized in that: The material of the pellets used in the high-energy shot peening process is selected from metal, ceramic or resin.

4. The method for preparing the 0-coated nano superhard non-stick liner according to claim 1, characterized in that: The diameter of the pellets processed by high-energy shot peening is 0.1-5 mm.

5. The method for preparing the 0-coated nano superhard non-stick liner according to claim 1, characterized in that: The high energy shot peening treatment lasts for 2-8 minutes.

6. The method for preparing the 0-coated nano superhard non-stick liner according to claim 1, characterized in that: The etching solution used in the etching process is an acidic FeCl3 solution.

7. The method for preparing the 0-coated nano superhard non-stick liner according to claim 6, characterized in that: The etching solution contains 150-300 g FeCl3, 45-65 mL hydrogen peroxide, and 0-65 mL hydrochloric acid per 1 L.

8. The method for preparing the 0-coating nano superhard non-stick liner according to claim 1, characterized in that: The temperature of the etching treatment is 20-80° C.; the time of the etching treatment is 20-100 min.

9. The method for preparing the 0-coated nano superhard non-stick liner according to claim 1, characterized in that: The treatment temperature of the low temperature heat treatment is 100-550° C.; the treatment time of the low temperature heat treatment is 10-60 min.

10. A 0-coating nano super-hard non-stick liner, characterized in that: The invention is prepared by the preparation method of the 0-coating nano superhard non-stick liner according to any one of claims 1 to 9.

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