Microwaveable enamelware and method of making same

Abstract

The present application belongs to the technical field of enamel material, and specifically discloses an enamel vessel capable of being put into a microwave oven, which comprises a metal base body and first, second and third enamel layers coated on the surface of the metal base body in sequence; the first enamel layer contains, in terms of mass percentage, 1-5% of titanium dioxide, 40-55% of silicon dioxide, 2-5% of zirconium dioxide, 30-40% of diboron trioxide, 3-5% of aluminum trioxide, 2-3% of cobalt oxide and 2-3% of nickel monoxide; the second enamel layer contains, in terms of mass percentage, 1-5% of titanium dioxide, 48-50% of silicon dioxide, 3-5% of zirconium dioxide, 35-40% of diboron trioxide and 4-5% of aluminum trioxide; and the third enamel layer contains, in terms of mass percentage, 1-5% of titanium dioxide, 48-50% of silicon dioxide, 3-5% of zirconium dioxide, 35-40% of diboron trioxide and 4-5% of aluminum trioxide, so that the protection of the metal base body is strengthened, the electric spark generated by the metal base body is avoided, and the reflection of microwaves is weakened, so that the microwave oven will not be damaged, and the purpose of being capable of being used in the microwave oven is achieved.

Description

Technical Field

[0001] This invention relates to the field of enamel material technology, and in particular to an enamelware that can be placed in a microwave oven and its preparation method. Background Technology

[0002] Enamel is an inorganic glass-ceramic enamel coating applied to the surface of a metal substrate. Applying enamel to a metal substrate prevents rusting, prevents oxidation when heated, and resists corrosion from various liquids. Enamel products are not only safe and non-toxic, but also easy to clean, making them widely applicable as tableware and washing utensils in daily life.

[0003] Ovens and microwave ovens are the most commonly used baking appliances for everyday consumers, so their baking performance directly affects the cooking experience. However, enamelware should not be placed in a microwave oven. When enamelware is placed in a microwave, the metal substrate generates electric sparks and reflects microwaves, which can damage the internal components of the microwave, preventing food from cooking properly. Furthermore, enamelware is relatively susceptible to temperature changes, especially in the localized heating environment of a microwave oven. This can cause the enamel layer to crack or peel off, exposing the metal parts and potentially causing the aforementioned problems, damaging the microwave or posing a safety hazard. Summary of the Invention

[0004] In order to overcome the defects of the existing technology, the present invention provides an enamelware that can be placed in a microwave oven and its preparation method, which solves the problem that when the enamelware is placed in a microwave oven for heating, the metal substrate will generate electric sparks and reflect microwaves, which will damage the internal components of the microwave oven.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] The first aspect of the present invention is to provide an enamelware that can be placed in a microwave oven, comprising a metal substrate and a first enamel layer, a second enamel layer and a third enamel layer sequentially coated and fired onto the surface of the metal substrate.

[0007] By weight percentage

[0008] The raw materials for the first ceramic enamel layer contain: 1-5% titanium dioxide, 40-55% silicon dioxide, 2-5% zirconium dioxide, 30-40% boron trioxide, 3-5% aluminum trioxide, 2-3% cobalt oxide, and 2-3% nickel oxide;

[0009] The raw materials for the second ceramic enamel layer contain: 1-5% titanium dioxide, 48-50% silicon dioxide, 3-5% zirconium dioxide, 35-40% boron trioxide, and 4-5% aluminum oxide;

[0010] The raw materials for the third enamel layer contain: 1-5% titanium dioxide, 48-50% silicon dioxide, 3-5% zirconium dioxide, 35-40% boron trioxide, and 4-5% aluminum oxide.

[0011] The solution addresses this problem by using silicon dioxide and zirconium dioxide in the ceramic enamel layer as microwave-absorbing materials. These materials absorb some of the microwaves emitted by the microwave oven. Furthermore, by sequentially coating the metal substrate with a first, second, and third ceramic enamel layer, each containing silicon dioxide and zirconium dioxide, the three-layer enamel layer provides better microwave absorption compared to a single-layer enamel layer. This enhances the protection of the metal substrate, prevents electrical sparks from forming on the substrate, and reduces microwave reflection, thus preventing damage to the microwave oven and enabling its use within the microwave oven.

[0012] As a further embodiment, the carbon content of the metal matrix is ​​0.01-0.1% by mass percentage.

[0013] Specifically, the carbon content of the metal substrate is low, between 0.01% and 0.1%. Iron plates are preferred as the metal substrate, meaning that the metal substrate is a low-carbon iron plate. This effectively reduces the generation of related gases in the metal substrate during the sintering process of the enamelware, allowing the enamel to bond better with the metal substrate. This results in better adhesion of the enamel layer, ensuring that the enamel adheres firmly to the surface of the metal substrate and is not easily peeled off, thus significantly reducing quality problems such as "ceramic cracking" and "scale cracking".

[0014] The second aspect of the present invention provides a method for preparing a microwave-safe enamelware, the method comprising the following steps:

[0015] S1, according to the formula, the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, aluminum oxide, cobalt oxide, and nickel oxide are loaded into a ball mill, water is added, and they are ground and mixed to obtain glaze slurry A; the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, and aluminum oxide are loaded into a ball mill, water is added, and they are ground and mixed to obtain glaze slurry B;

[0016] S2, the metal substrate is immersed in glaze slurry A for the first glazing. After immersion, the substrate is removed and the slurry on the surface of the metal substrate is shaken evenly. Then, it is dried at 100-200℃ for 10-30 minutes, followed by firing at 820-850℃ for 3-5 minutes. After firing, it is placed at room temperature to cool and form the first glaze layer, resulting in semi-finished product A.

[0017] S3. Immerse semi-finished product A in glaze slurry B for a second glazing. After immersion, remove the product and shake the slurry on the surface of semi-finished product A to evenly distribute it. Then, dry it at 100-200℃ for 10-30 minutes, followed by firing at 810-830℃ for 3-5 minutes. After firing, allow it to cool at room temperature to form the second glaze layer, thus obtaining semi-finished product B.

[0018] S4. Immerse the semi-finished product B in glaze slurry B for the third glazing. After immersion, take it out and shake the slurry on the surface of the semi-finished product B evenly. Then dry it at 100-200℃ for 10-30 minutes. After that, fire it at 800-820℃ for 3-5 minutes. After firing, place it at room temperature to cool and form the third glaze layer, thus obtaining the enamelware.

[0019] Specifically, in the preparation method of enamelware, high-temperature firing above 800℃ has the following advantages compared to low-temperature firing:

[0020] ① Improve the resistance of the enamel layer to thermal shock, and avoid cracking or splitting of the enamel layer due to sudden temperature changes; at the same time, improve the high temperature resistance of the enamel layer, so that the enamel layer of enamelware can better maintain structural stability and surface color in high-temperature cooking environment, and avoid structural damage or color change.

[0021] ② Improve the chemical corrosion resistance of the enamel layer to prevent it from peeling off, being damaged, or discoloring when it comes into long-term contact with certain acidic or alkaline substances.

[0022] ③ Improve the bonding force between the enamel and the metal substrate, resulting in a tighter bond and thus improving the adhesion of the enamel layer, preventing the enamel layer from chipping or peeling off due to collisions or friction.

[0023] At the same time, by applying glaze and firing it in three stages, a first glaze layer, a second glaze layer and a third glaze layer can be formed. Compared with a single glaze layer, the three-layer glaze layer can better absorb microwaves, thereby strengthening the protection of the metal substrate.

[0024] As a further option, in step S1, after the glaze slurry A is ground and mixed, the remaining weight after being screened through a 200-mesh sieve is 2-6g, and the specific gravity of the slurry is controlled at 1.65-1.75.

[0025] As a further option, in step S1, after the glaze slurry B is ground and mixed, the remaining weight after being screened through a 200-mesh sieve is 2-4g, and the specific gravity of the slurry is controlled at 1.55-1.65.

[0026] The beneficial effects of this invention are:

[0027] 1. In this design, the silica and zirconium dioxide in the enamel layer act as microwave absorbing materials, which can absorb microwaves in the microwave oven. Furthermore, by sequentially coating the metal substrate with a first, second, and third enamel layer, each of which contains silica and zirconium dioxide, the three-layer enamel layer can better absorb microwaves compared to a single-layer enamel layer. This strengthens the protection of the metal substrate, prevents electrical sparks from being generated on the metal substrate, and reduces microwave reflection, thus preventing damage to the microwave oven and achieving the goal of being usable in a microwave oven.

[0028] 2. The metal substrate is a low-carbon iron plate, which effectively reduces the generation of related gases in the metal substrate during the sintering process of enamelware. The enamel material and the metal substrate are better bonded, resulting in better adhesion of the enamel layer. The enamel material of the enamel layer is firmly attached to the surface of the metal substrate and is not easy to peel off, which greatly reduces the quality problems of "porcelain cracking" and "scale cracking".

[0029] 3. In the preparation methods of enamelware, high-temperature firing above 800℃ has the following advantages compared to low-temperature firing:

[0030] ① Improve the resistance of the enamel layer to thermal shock, and avoid cracking or splitting of the enamel layer due to sudden temperature changes; at the same time, improve the high temperature resistance of the enamel layer, so that the enamel layer of enamelware can better maintain structural stability and surface color in high-temperature cooking environment, and avoid structural damage or color change.

[0031] ② Improve the chemical corrosion resistance of the enamel layer to prevent it from peeling off, being damaged, or discoloring when it comes into long-term contact with certain acidic or alkaline substances.

[0032] ③ Improve the bonding force between the enamel and the metal substrate, resulting in a tighter bond and thus improving the adhesion of the enamel layer, preventing the enamel layer from chipping or peeling off due to collisions or friction. Detailed Implementation

[0033] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] It should be noted that in the following embodiments, the carbon content of the metal substrate is 0.01-0.1%, preferably 0.06%, and it is a low-carbon iron plate. The enamelware has an open structure, allowing microwaves in the microwave oven to heat the food in the ware through the opening.

[0035] Example 1

[0036] A microwave-safe enamelware includes a metal substrate and a first enamel layer, a second enamel layer, and a third enamel layer sequentially coated and fired onto the surface of the metal substrate.

[0037] By weight percentage

[0038] The raw materials for the first enamel layer contain: 3% titanium dioxide, 50% silicon dioxide, 3% zirconium dioxide, 35% boron trioxide, 4% aluminum trioxide, 2% cobalt oxide, and 3% nickel oxide;

[0039] The raw materials for the second enamel layer contain: 1% titanium dioxide, 50% silicon dioxide, 5% zirconium dioxide, 40% boron trioxide, and 4% aluminum oxide;

[0040] The raw materials for the third enamel layer contain: 1% titanium dioxide, 50% silicon dioxide, 5% zirconium dioxide, 40% boron trioxide, and 4% aluminum oxide.

[0041] A method for preparing a microwave-safe enamelware dish includes the following steps:

[0042] S1. According to the formula, the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, aluminum oxide, cobalt oxide, and nickel oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-6g, and the specific gravity of the slurry is controlled between 1.65-1.75, to obtain glaze slurry A; The raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, and aluminum oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-4g, and the specific gravity of the slurry is controlled between 1.55-1.65, to obtain glaze slurry B;

[0043] S2, the metal substrate is immersed in glaze slurry A for the first glazing. After immersion, the substrate is removed and the slurry on the surface of the metal substrate is shaken evenly. Then it is dried at 150℃ for 20 minutes, and then fired at 850℃ for 4 minutes. After firing, it is placed at room temperature to cool and form the first glaze layer, thus obtaining semi-finished product A.

[0044] S3, immerse semi-finished product A in glaze slurry B for a second glazing. After immersion, remove the product and shake the slurry on the surface of semi-finished product A to evenly distribute it. Then dry it at 150℃ for 20 minutes, followed by firing at 830℃ for 4 minutes. After firing, allow it to cool at room temperature to form the second glaze layer, thus obtaining semi-finished product B.

[0045] S4. Immerse the semi-finished product B in glaze slurry B for the third glazing. After immersion, take it out and shake the slurry on the surface of the semi-finished product B evenly. Then dry it at 150℃ for 20 minutes, and then fire it at 820℃ for 4 minutes. After firing, place it at room temperature to cool and form the third glaze layer, thus obtaining the enamelware.

[0046] Example 2

[0047] A microwave-safe enamelware includes a metal substrate and a first enamel layer, a second enamel layer, and a third enamel layer sequentially coated and fired onto the surface of the metal substrate.

[0048] By weight percentage

[0049] The raw materials for the first enamel layer contain: 1% titanium dioxide, 55% silicon dioxide, 2% zirconium dioxide, 34% boron trioxide, 3% aluminum trioxide, 3% cobalt oxide, and 2% nickel oxide;

[0050] The raw materials for the second enamel layer contain: 5% titanium dioxide, 50% silicon dioxide, 5% zirconium dioxide, 35% boron trioxide, and 5% aluminum oxide;

[0051] The raw materials for the third enamel layer contain: 5% titanium dioxide, 50% silicon dioxide, 5% zirconium dioxide, 35% boron trioxide, and 5% aluminum oxide.

[0052] A method for preparing a microwave-safe enamelware dish includes the following steps:

[0053] S1. According to the formula, the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, aluminum oxide, cobalt oxide, and nickel oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-6g, and the specific gravity of the slurry is controlled between 1.65-1.75, to obtain glaze slurry A; The raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, and aluminum oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-4g, and the specific gravity of the slurry is controlled between 1.55-1.65, to obtain glaze slurry B;

[0054] S2, the metal substrate is immersed in glaze slurry A for the first glazing. After immersion, the substrate is removed and the slurry on the surface of the metal substrate is shaken evenly. Then it is dried at 150℃ for 20 minutes, and then fired at 830℃ for 4 minutes. After firing, it is placed at room temperature to cool and form the first glaze layer, thus obtaining semi-finished product A.

[0055] S3, immerse semi-finished product A in glaze slurry B for a second glazing. After immersion, remove the product and shake the slurry on the surface of semi-finished product A to evenly distribute it. Then dry it at 150℃ for 20 minutes, followed by firing at 820℃ for 4 minutes. After firing, allow it to cool at room temperature to form the second glaze layer, thus obtaining semi-finished product B.

[0056] S4. Immerse the semi-finished product B in glaze slurry B for the third glazing. After immersion, take it out and shake the slurry on the surface of the semi-finished product B evenly. Then dry it at 150℃ for 20 minutes, and then fire it at 810℃ for 4 minutes. After firing, place it at room temperature to cool and form the third glaze layer, thus obtaining the enamelware.

[0057] Example 3

[0058] A microwave-safe enamelware includes a metal substrate and a first enamel layer, a second enamel layer, and a third enamel layer sequentially coated and fired onto the surface of the metal substrate.

[0059] By weight percentage

[0060] The raw materials for the first enamel layer contain: 5% titanium dioxide, 40% silicon dioxide, 5% zirconium dioxide, 40% boron trioxide, 5% aluminum trioxide, 3% cobalt oxide, and 2% nickel oxide;

[0061] The raw materials for the second enamel layer contain: 3% titanium dioxide, 50% oxide, 3% oxide, 40% boron trioxide, and 4% aluminum oxide;

[0062] The raw materials for the third enamel layer contain: 3% titanium dioxide, 50% silicon dioxide, 3% zirconium dioxide, 40% boron trioxide, and 4% aluminum trioxide.

[0063] A method for preparing a microwave-safe enamelware dish includes the following steps:

[0064] S1. According to the formula, the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, aluminum oxide, cobalt oxide, and nickel oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-6g, and the specific gravity of the slurry is controlled between 1.65-1.75, to obtain glaze slurry A; The raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, and aluminum oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-4g, and the specific gravity of the slurry is controlled between 1.55-1.65, to obtain glaze slurry B;

[0065] S2, the metal substrate is immersed in glaze slurry A for the first glazing. After immersion, the substrate is removed and the slurry on the surface of the metal substrate is shaken evenly. Then it is dried at 150℃ for 20 minutes, and then fired at 850℃ for 4 minutes. After firing, it is placed at room temperature to cool and form the first glaze layer, thus obtaining semi-finished product A.

[0066] S3, immerse semi-finished product A in glaze slurry B for a second glazing. After immersion, remove the product and shake the slurry on the surface of semi-finished product A to evenly distribute it. Then dry it at 150℃ for 20 minutes, followed by firing at 830℃ for 4 minutes. After firing, allow it to cool at room temperature to form the second glaze layer, thus obtaining semi-finished product B.

[0067] S4. Immerse the semi-finished product B in glaze slurry B for the third glazing. After immersion, take it out and shake the slurry on the surface of the semi-finished product B evenly. Then dry it at 150℃ for 20 minutes, and then fire it at 810℃ for 4 minutes. After firing, place it at room temperature to cool and form the third glaze layer, thus obtaining the enamelware.

[0068] Example 4

[0069] A microwave-safe enamelware includes a metal substrate and a first enamel layer, a second enamel layer, and a third enamel layer sequentially coated and fired onto the surface of the metal substrate.

[0070] By weight percentage

[0071] The raw materials for the first enamel layer contain: 5% titanium dioxide, 50% silicon dioxide, 5% zirconium dioxide, 30% boron trioxide, 5% aluminum trioxide, 3% cobalt oxide, and 2% nickel oxide;

[0072] The raw materials for the second enamel layer contain: 1% titanium dioxide, 50% sulfur dioxide, 5% zirconium dioxide, 39% boron trioxide, and 5% aluminum oxide;

[0073] The raw materials for the third enamel layer contain: 1% titanium dioxide, 50% silicon dioxide, 5% zirconium dioxide, 39% boron trioxide, and 5% aluminum oxide.

[0074] A method for preparing a microwave-safe enamelware dish includes the following steps:

[0075] S1. According to the formula, the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, aluminum oxide, cobalt oxide, and nickel oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-6g, and the specific gravity of the slurry is controlled between 1.65-1.75, to obtain glaze slurry A; The raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, and aluminum oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-4g, and the specific gravity of the slurry is controlled between 1.55-1.65, to obtain glaze slurry B;

[0076] S2, the metal substrate is immersed in glaze slurry A for the first glazing. After immersion, the substrate is removed and the slurry on the surface of the metal substrate is shaken evenly. Then it is dried at 150℃ for 20 minutes, and then fired at 820℃ for 4 minutes. After firing, it is placed at room temperature to cool and form the first glaze layer, thus obtaining semi-finished product A.

[0077] S3, immerse semi-finished product A in glaze slurry B for a second glazing. After immersion, remove the product and shake the slurry on the surface of semi-finished product A to evenly distribute it. Then dry it at 150℃ for 20 minutes, followed by firing at 810℃ for 4 minutes. After firing, allow it to cool at room temperature to form the second glaze layer, thus obtaining semi-finished product B.

[0078] S4. Immerse the semi-finished product B in glaze slurry B for the third glazing. After immersion, take it out and shake the slurry on the surface of the semi-finished product B evenly. Then dry it at 150℃ for 20 minutes, and then fire it at 800℃ for 4 minutes. After firing, place it at room temperature to cool and form the third glaze layer, thus obtaining the enamelware.

[0079] Example 5

[0080] A microwave-safe enamelware includes a metal substrate and a first enamel layer, a second enamel layer, and a third enamel layer sequentially coated and fired onto the surface of the metal substrate.

[0081] By weight percentage

[0082] The raw materials for the first enamel layer contain: 1% titanium dioxide, 53% silicon dioxide, 2% zirconium dioxide, 35% boron trioxide, 5% aluminum trioxide, 2% cobalt oxide, and 2% nickel oxide;

[0083] The raw materials for the second enamel layer contain: 2% titanium dioxide, 48% silicon dioxide, 5% zirconium dioxide, 40% boron trioxide, and 5% aluminum oxide;

[0084] The raw materials for the third enamel layer contain: 2% titanium dioxide, 48% silicon dioxide, 5% zirconium dioxide, 40% boron trioxide, and 5% aluminum oxide.

[0085] A method for preparing a microwave-safe enamelware dish includes the following steps:

[0086] S1. According to the formula, the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, aluminum oxide, cobalt oxide, and nickel oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After sieving through a 200-mesh sieve, the remaining weight is controlled between 2-6g, and the specific gravity of the slurry is controlled between 1.65-1.75, to obtain glaze slurry A; The raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, and aluminum oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After sieving through a 200-mesh sieve, the remaining weight is controlled between 2-4g, and the specific gravity of the slurry is controlled between 1.55-1.65, to obtain glaze slurry B;

[0087] S2, the metal substrate is immersed in glaze slurry A for the first glazing. After immersion, the substrate is removed and the slurry on the surface of the metal substrate is shaken evenly. Then it is dried at 150℃ for 20 minutes, and then fired at 820℃ for 4 minutes. After firing, it is placed at room temperature to cool and form the first glaze layer, thus obtaining semi-finished product A.

[0088] S3, immerse semi-finished product A in glaze slurry B for a second glazing. After immersion, remove the product and shake the slurry on the surface of semi-finished product A to evenly distribute it. Then dry it at 150℃ for 20 minutes, followed by firing at 810℃ for 4 minutes. After firing, allow it to cool at room temperature to form the second glaze layer, thus obtaining semi-finished product B.

[0089] S4. Immerse the semi-finished product B in glaze slurry B for the third glazing. After immersion, take it out and shake the slurry on the surface of the semi-finished product B evenly. Then dry it at 150℃ for 20 minutes, and then fire it at 800℃ for 4 minutes. After firing, place it at room temperature to cool and form the third glaze layer, thus obtaining the enamelware.

[0090] Comparative Example 1 (The difference from Example 1 is that in the preparation method of the enamelware, steps S2, S3, and S4 are fired at a low temperature, while the others remain the same)

[0091] A microwave-safe enamelware includes a metal substrate and a first enamel layer, a second enamel layer, and a third enamel layer sequentially coated and fired onto the surface of the metal substrate.

[0092] By weight percentage

[0093] The raw materials for the first enamel layer contain: 3% titanium dioxide, 50% silicon dioxide, 3% zirconium dioxide, 35% boron trioxide, 4% aluminum trioxide, 2% cobalt oxide, and 3% nickel oxide;

[0094] The raw materials for the second enamel layer contain: 1% titanium dioxide, 50% silicon dioxide, 5% zirconium dioxide, 40% boron trioxide, and 4% aluminum oxide;

[0095] The raw materials for the third enamel layer contain: 1% titanium dioxide, 50% silicon dioxide, 5% zirconium dioxide, 40% boron trioxide, and 4% aluminum oxide.

[0096] A method for preparing a microwave-safe enamelware dish includes the following steps:

[0097] S1. According to the formula, the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, aluminum oxide, cobalt oxide, and nickel oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-6g, and the specific gravity of the slurry is controlled between 1.65-1.75, to obtain glaze slurry A; The raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, and aluminum oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After screening through a 200-mesh sieve, the remaining weight is controlled between 2-4g, and the specific gravity of the slurry is controlled between 1.55-1.65, to obtain glaze slurry B;

[0098] S2, the metal substrate is immersed in glaze slurry A for the first glazing. After immersion, the substrate is removed and the slurry on the surface of the metal substrate is shaken evenly. Then it is dried at 150℃ for 20 minutes, and then fired at 610℃ for 4 minutes. After firing, it is placed at room temperature to cool and form the first glaze layer, thus obtaining semi-finished product A.

[0099] S3, immerse semi-finished product A in glaze slurry B for a second glazing. After immersion, remove the product and shake the slurry on the surface of semi-finished product A to evenly distribute it. Then dry it at 150℃ for 20 minutes, followed by firing at 610℃ for 4 minutes. After firing, place it at room temperature to cool and form the second glaze layer, thus obtaining semi-finished product B.

[0100] S4. Immerse the semi-finished product B in glaze slurry B for the third glazing. After immersion, take it out and shake the slurry on the surface of the semi-finished product B evenly. Then dry it at 150℃ for 20 minutes, and then fire it at 600℃ for 4 minutes. After firing, place it at room temperature to cool and form the third glaze layer, thus obtaining the enamelware.

[0101] Comparative Example 2 (The difference from Example 1 is that the carbon content of the metal matrix is ​​1.5%, while all other aspects remain the same)

[0102] Comparative Example 3 (The difference from Example 1 is that only one layer of porcelain enamel is applied to the surface of the metal substrate, while the rest remains the same)

[0103] A microwave-safe enamelware includes a metal substrate and a porcelain enamel layer coated on the surface of the metal substrate.

[0104] By mass percentage, the raw materials of the enamel layer contain: 3% titanium dioxide, 50% silicon dioxide, 3% zirconium dioxide, 35% boron trioxide, 4% aluminum trioxide, 2% cobalt oxide, and 3% nickel oxide.

[0105] A method for preparing a microwave-safe enamelware dish includes the following steps:

[0106] S1. According to the formula, the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, boron trioxide, aluminum trioxide, cobalt oxide, and nickel oxide are loaded into a ball mill, water is added, and the mixture is ground and mixed. After being screened through a 200-mesh sieve, the remaining weight is controlled between 2-6g, and the specific gravity of the slurry is controlled between 1.65-1.75 to obtain the glaze slurry.

[0107] S2, immerse the metal substrate in the glaze slurry for glazing, remove it after immersion and shake the slurry on the surface of the metal substrate evenly, then dry it at 150℃ for 20 minutes, then fire it at 850℃ for 4 minutes, and after firing, place it at room temperature to cool and form a porcelain glaze layer to obtain enamelware.

[0108] Performance testing

[0109] 1) Feasibility test of enamelware in microwave ovens.

[0110] Test objective: To test whether enamelware can be heated in a microwave oven and whether it will damage the microwave oven.

[0111] Testing equipment: microwave oven, temperature gun.

[0112] Test steps: ① Fill the lunchbox with 1 / 3 room temperature water; ② Place the lunchbox in the microwave oven and close the microwave oven door; ③ Turn on the microwave oven (set to high power / 10 minutes); ④ After microwaving, remove the lunchbox and check if the enamelware has been heated.

[0113] Quality assessment: The enamelware showed no signs of heating, and the microwave oven did not exhibit any abnormalities during the test.

[0114] The enamelware obtained in Examples 1-5 and Comparative Example 3 were subjected to this test, and the results are shown in Table 1 below:

[0115] Table 1:

[0116]

[0117] The above tests show that the enamelware of the present invention can be used in a microwave oven without damaging it. Since the microwave-absorbing material in the enamel layer heats up after absorbing microwaves, and the surface temperature of the enamelware in Comparative Example 3 is lower than that in Examples 1-5, it indicates that the enamel layer in Examples 1-5 has a significantly stronger microwave absorption effect than that in Comparative Example 3. Compared to a single-layer enamel layer, the three-layer enamel layer can absorb microwaves better, thereby strengthening the protection of the metal substrate, preventing electric sparks from being generated on the metal substrate, and reducing microwave reflection.

[0118] 2) Porcelain glaze adhesion test.

[0119] Test objective: To ensure the product's performance.

[0120] Test equipment: Impact test frame (impact rod weight 2kg, impact height 750mm, test rod 15mm).

[0121] Test steps: ① Before testing, check whether the ceramic has cracked and whether the surface layer thickness is uniform; ② Place the sample under the test bar of the impact tester (the test bar must be pressed on the sample plane); ③ Then drop a 2kg impact bar from a height of 750mm onto the test bar to deform the sample at the impact point; ④ Repeat steps ② and ③, and impact any 3 points on the plane.

[0122] Quality assessment: Observe the degree of damage to the glaze layer and compare it with the specified requirements.

[0123] Note: The glaze adhesion ratio is the ratio of the area of ​​glaze residue at the impact deformation site to the area of ​​the impact deformation site.

[0124] ① Poor adhesion: After impact, no glaze adheres to the metal substrate at the impact deformation site, and the edges of the impact deformation site peel off in flakes.

[0125] ② Adhesion failure: less than 24% of the glaze at the impact deformation site is adhered to the metal substrate, but there is no flaking at the edge of the impact deformation site and the glaze is still attached.

[0126] ③ Adhesion qualified: After impact deformation, 25%-49% of the glaze adheres to the metal substrate, and the glaze is distributed in a ring shape (there should be no flaking).

[0127] ④ Good (Grade A): After impact, the glaze at the impact deformation site is distributed in a ring shape (there should be no flaking), and 50%-74% of the glaze is adhered;

[0128] ⑤ Excellent adhesion (AA grade): After impact deformation, more than 75% of the glaze adheres to the metal substrate and there is no porcelain chipping or peeling.

[0129] The enamelware obtained in Example 1 and Comparative Examples 1-2 were subjected to this test, and the test results are shown in Table 2 below:

[0130] Table 2:

[0131]

[0132] The above tests show that the enamel glaze layer of the enamelware of the present invention has good adhesion. The glaze adhesion ratio in Example 1 is significantly higher than that in Comparative Example 1, indicating that high-temperature firing at 800°C or above, compared with low-temperature firing, can improve the bonding force between the enamel glaze and the metal substrate, resulting in a tighter bond and thus improving the adhesion of the enamel layer.

[0133] Meanwhile, the glaze adhesion ratio in Example 1 was significantly higher than that in Comparative Example 2, indicating that the low carbon content of the metal substrate effectively reduces the generation of related gases during the sintering process of enamelware, and the glaze and metal substrate bond better, thus giving the glaze layer better adhesion.

[0134] 3) Acid resistance test of porcelain enamel layer.

[0135] Test objective: To ensure the product's performance.

[0136] Testing equipment: citric acid, qualitative filter paper, graduated cylinder, measuring cup, stirring rod, cotton cloth, electronic scale.

[0137] Test steps: ① Before testing, clean the surface of the product to remove any dirt or impurities; ② Weigh 5 grams of citric acid using an electronic scale and measuring cup, and then measure 50 ml of water using a measuring cylinder; ③ Slowly pour 50 ml of water into the prepared 5 grams of citric acid, and stir the citric acid granules and water evenly with a stirring rod; ④ Hold the prepared qualitative filter paper by hand and dip it into the citric acid, then immediately remove it and stick it onto a clean enamel surface for 15 minutes; ⑤ After 15 minutes, peel off the qualitative filter paper, wipe the citric acid off the enamel surface with a clean cotton cloth, and observe whether the surface of the test sample changes color.

[0138] Quality assessment: Hold the qualitative filter paper in your hand and dip it into 10% citric acid. Immediately remove it and stick it on a clean enamel surface. After 15 minutes, tear off the test paper and wipe it dry. If there is no color change, it is qualified.

[0139] The enamelware obtained in Example 1 and Comparative Example 1 were subjected to this test, and the test results are shown in Table 3 below:

[0140] Table 3:

[0141]

[0142] From the above tests, it can be seen that the enamel layer of the enamelware of the present invention is qualified in acid resistance. The enamel layer of Example 1 did not change color, while that of Comparative Example 1 changed color, indicating that firing at a high temperature above 800 °C can improve the chemical corrosion resistance of the enamel layer compared to firing at a low temperature.

[0143] 4) Test for the resistance of the enamel layer to thermal shock.

[0144] Test purpose: To ensure the service performance of the product.

[0145] Test equipment: Thermostatic chamber.

[0146] Test steps: 1) Before the test, check whether the product has burst, cracked or surface decoloration; 2) Heat the thermostatic chamber to 220 ± 5 °C, and then put the randomly sampled enamelware into the thermostatic chamber for 20 minutes; 3) After 20 minutes, take it out and put it into water at 20 ± 5 °C to observe whether there is enamel peeling and decoloration of the product; 4) After drying the enamelware that has passed the test and heated to 220 ± 5 °C, adjust the temperature of the thermostatic chamber to 240 ± 5 °C, and then put it into the oven for 20 minutes; 5) After 20 minutes, take it out and put it into water at 20 ± 5 °C to observe whether there is enamel peeling and decoloration of the product; 6) After drying the enamelware that has passed the test and heated to 240 ± 5 °C, adjust the temperature of the thermostatic chamber to 260 ± 5 °C, and then put it into the oven for 20 minutes; 7) After 20 minutes, take it out and put it into water at 20 ± 5 °C to observe whether there is enamel peeling and decoloration of the product; 8) After drying the enamelware that has passed the test and heated to 260 ± 5 °C, adjust the temperature of the thermostatic chamber to 280 ± 5 °C, and then put it into the oven for 20 minutes; 9) After 20 minutes, take it out and put it into water at 20 ± 5 °C to observe whether there is enamel peeling and decoloration of the product; 10) After drying the enamelware that has passed the test and heated to 280 ± 5 °C, adjust the temperature of the thermostatic chamber to 300 ± 5 °C, and then put it into the oven for 20 minutes; 11) After 20 minutes, take it out and put it into water at 20 ± 5 °C to observe whether there is enamel peeling and decoloration of the product.

[0147] Quality assessment: Place the randomly sampled enamelware in the thermostatic chamber and keep the temperature at 220 ± 5 °C, and then take it out after 20 minutes of constant temperature and put it into cold water at 20 ± 5 °C. Observe that there is no enamel peeling and the surface of the product has no decoloration. Passing the test that there is no enamel peeling and no surface decoloration when taken out from 220 ± 5 °C and put into cold water at 20 ± 5 °C is considered qualified.

[0148] The enamelware obtained in Example 1 and Comparative Example 1 were subjected to this test, and the test results are shown in Table 4 below:

[0149] Table 4:

[0150]

[0151] The above tests show that the enamelware of the present invention has a high resistance to thermal shock. This indicates that firing at a high temperature above 800°C can improve the resistance to thermal shock of the enamel layer compared to firing at a low temperature, and avoid the enamel layer from cracking or splitting due to sudden temperature changes.

[0152] The embodiments of the present invention have been 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 can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A microwaveable enamelware vessel characterized by: The metal base and the first, second and third enamel layers coated on the surface of the metal base in sequence; By mass percentage, The raw materials of the first enamel layer contain 1-5% of titanium dioxide, 40-55% of silicon dioxide, 2-5% of zirconium dioxide, 30-40% of diboron trioxide, 3-5% of aluminum trioxide, 2-3% of cobalt oxide and 2-3% of nickel monoxide; The raw materials of the second enamel layer contain 1-5% of titanium dioxide, 48-50% of silicon dioxide, 3-5% of zirconium dioxide, 35-40% of diboron trioxide and 4-5% of aluminum trioxide; The raw materials of the third enamel layer contain 1-5% of titanium dioxide, 48-50% of silicon dioxide, 3-5% of zirconium dioxide, 35-40% of diboron trioxide and 4-5% of aluminum trioxide; The metal base contains 0.01-0.1% of carbon by mass percentage.

2. A method of making a microwaveable enamelware vessel, characterized by: The preparation method is used for producing the enamel vessel capable of being put into a microwave oven in claim 1, and the preparation method comprises the following steps: S1, proportioning and dosing, filling the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide, diboron trioxide, aluminum trioxide, cobalt oxide and nickel monoxide into a ball mill to mix and grind with water to obtain glaze slurry A; filling the raw materials containing titanium dioxide, silicon dioxide, zirconium dioxide and aluminum trioxide into a ball mill to mix and grind with water to obtain glaze slurry B; S2, immersing the metal base into the glaze slurry A to perform the first glazing, taking out after immersion and shaking the glaze slurry on the surface of the metal base uniformly, then drying at 100-200 ℃ for 10-30 min, then firing at 820-850 ℃ for 3-5 min, and then cooling at room temperature after firing to form the first enamel layer, thereby obtaining semi-product A; S3, immersing the semi-product A into the glaze slurry B to perform the second glazing, taking out after immersion and shaking the glaze slurry on the surface of the semi-product A uniformly, then drying at 100-200 ℃ for 10-30 min, then firing at 810-830 ℃ for 3-5 min, and then cooling at room temperature after firing to form the second enamel layer, thereby obtaining semi-product B; S4, immersing the semi-product B into the glaze slurry B to perform the third glazing, taking out after immersion and shaking the glaze slurry on the surface of the semi-product B uniformly, then drying at 100-200 ℃ for 10-30 min, then firing at 800-820 ℃ for 3-5 min, and then cooling at room temperature after firing to form the third enamel layer, thereby obtaining the enamel vessel.

3. A method of making a microwaveable enamelware vessel according to claim 2, wherein: In step S1, the residual amount of the glaze slurry A after screening through a 200-mesh screen is 2-6 g, and the powder slurry specific gravity is controlled to be 1.65-1.

75.

4. A method of making a microwaveable enamelware vessel according to claim 2, wherein: In step S1, the residual amount of the glaze slurry B after screening through a 200-mesh screen is 2-4 g, and the powder slurry specific gravity is controlled to be 1.55-1.65.

Images