In-situ reaction based on transient template for enamel frit and preparation method and application thereof

Abstract

The application belongs to the technical field of enamel glaze, and particularly relates to an enamel glaze based on in-situ reaction of a transient template, a preparation method and application thereof. The enamel glaze is mixed by a basic enamel glaze slurry and a core-shell structure functional precursor. The basic enamel glaze slurry is a water suspension prepared by mixing a basic enamel frit and an additive and then grinding. The core-shell structure functional precursor is an inorganic composite powder, and the original structure is that a silicon nitride micron particle is taken as a core, and a Y-Zr-Ti composite oxide is taken as a shell. The application realizes a real chemical bonding strong interface. By using a high-activity oxide shell layer as a solder in the final sintering stage, a firm chemical bond is constructed in-situ between a reinforced phase and a glass matrix. This fundamentally solves the problem of weak interface in traditional physical blending, so that stress can be effectively transmitted from the matrix to the high-strength reinforced phase.

Description

Technical Field

[0001] This invention belongs to the field of enamel glaze technology, specifically relating to enamel glaze based on transient template in-situ reaction, its preparation method, and its application. Background Technology

[0002] Enamel, also known as porcelain enamel, is a composite material formed by applying an inorganic vitreous enamel to a metal substrate (such as steel plate or cast iron) and firing it at high temperatures to create a strong bond between the two. With its smooth and beautiful surface, excellent chemical corrosion resistance, easy cleaning, and non-toxic properties, enamel products are widely used in daily utensils, architectural decoration, chemical industry, and electronics. However, traditional enamel coatings are essentially glassy materials, which inherently presents two major performance bottlenecks: high brittleness and insufficient mechanical properties. In practical use, when enamel products are subjected to external impacts, friction, or significant temperature changes, the coating is prone to cracking and peeling, which greatly limits its application in more demanding working conditions.

[0003] To improve the mechanical properties of enamel, the most common improvement method in existing technologies is to introduce high-hardness, high-strength ceramic particles, such as Al2O3, SiC, and ZrO3, into the enamel glaze as reinforcing phases to prepare ceramic particle-reinforced enamel composite coatings. This method typically employs physical blending, where the reinforcing particles and the raw materials of the base enamel frit are ball-milled together for extended periods with high energy consumption to obtain a uniformly dispersed glaze slurry. However, this traditional physical blending technique suffers from the following fundamental and insurmountable defects: First, there is a lack of effective chemical bonding between the reinforcing particles and the glass matrix, relying solely on physical wetting and mechanical locking. This physical interface is typically weak; under external force, stress cannot be effectively transferred from the softer glass matrix to the high-strength reinforcing particles. Cracks easily propagate along the particle-matrix interface, causing the particles to be "pulled out," failing to exert their intended reinforcing and toughening effects, resulting in limited improvement in the coating's wear resistance and adhesion strength. At the same time, while simply increasing the content of hard particles can improve hardness to some extent, it often sacrifices the density and toughness of the coating due to interface and agglomeration problems, and may even lead to a decrease in corrosion resistance.

[0004] Therefore, there is an urgent need in this field for a novel reinforced enamel technology that can fundamentally solve the problem of interfacial bonding between the reinforcing phase and the glass matrix. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide an enamel glaze based on transient template in-situ reaction, which plays a role in application by mixing a basic enamel glaze slurry with a core-shell structured functional precursor.

[0006] The present invention also provides a preparation method that is simple, easy to implement, and suitable for large-scale production.

[0007] The present invention also provides its application, in which an in-situ interfacial reaction occurs during the application process, forming a strong chemical bond interface, thereby improving the hardness and peel resistance of the enamel finished product.

[0008] The enamel glaze based on transient template in-situ reaction of the present invention is composed of a basic enamel glaze slurry and a core-shell structure functional precursor. The basic enamel glaze slurry is an aqueous suspension prepared by mixing and grinding a basic enamel frit and an additive. The mixing mass ratio of the basic enamel frit and the core-shell structure functional precursor is 100:(5~25).

[0009] The basic enamel frit is composed of the following parts by weight of raw materials:

[0010] SiO2: 40-55 parts;

[0011] B2O3: 14-20 parts;

[0012] Na2O: 8-15 parts;

[0013] K2O: 1-5 parts;

[0014] Li2O: 0.5~2.5 parts;

[0015] Al2O3: 2-8 parts;

[0016] CaO: 1-6 parts;

[0017] CoO: 0.5~1.5 parts;

[0018] NiO: 0.5~1.5 parts;

[0019] The core-shell structured functional precursor is a pretreated, stable inorganic composite powder whose original structure is: a core of silicon nitride (α-Si3N4) micron particles, and a shell of Y-Zr-Ti composite oxide formed by low-temperature calcination.

[0020] The average particle size of silicon nitride micron particles is 0.5~5μm.

[0021] The molar ratio of the elements in the Y-Zr-Ti composite oxide is ZrO2:TiO2:Y2O3 = (0.6~0.9):(0.1~0.4):(0.03~0.08).

[0022] The core-shell structured functional precursor has a core mass ratio of 60-62% and a shell mass ratio of 38-40%.

[0023] The preparation method of the core-shell structured functional precursor includes the following steps:

[0024] a. Activation of the nucleus surface

[0025] Add silicon nitride micro powder to a 25 wt.% hydrogen peroxide solution, heat and stir to perform hydroxylation, filter and wash until neutral, and then dry (dry at 130℃ for 6~10h) to obtain silicon nitride core with surface hydroxyl activation;

[0026] b. Homogeneous precipitation coating

[0027] The surface-hydroxyl-activated silicon nitride nuclei were dispersed with urea in water to form a suspension. A solution of titanium salt, zirconium salt, and yttrium salt was added to the suspension, and the mixture was heated and stirred (90℃, 7h). Metal hydroxides were uniformly precipitated on the surface of the silicon nitride particles to form a coating layer. After the reaction was completed, the product was subjected to solid-liquid separation and washed with deionized water.

[0028] c. Drying and low-temperature calcination

[0029] The washed powder was vacuum dried at 70-75℃ for 20 hours. The dried powder was then placed in a muffle furnace and heated to 550-600℃ at a rate of 5℃ / min under air atmosphere, and held at that temperature for 1.5-2.5 hours. After cooling, the core-shell structured functional precursor powder was obtained.

[0030] The method for preparing enamel glaze based on transient template in-situ reaction according to the present invention includes the following steps:

[0031] (1) Preparation of basic enamel frit

[0032] The basic enamel frit raw material is heated to 1200~1250℃ at a rate of 10℃ / min and melted for 100min. After melting, the resulting glass melt is poured into water for water quenching to obtain fragmented enamel frit.

[0033] (2) Preparation of basic enamel glaze slurry

[0034] After drying the enamel frit, it is mixed with additives and water, ground, and aged to obtain the basic enamel glaze slurry.

[0035] Specifically, the glaze slurry is placed in a ball mill for ball milling until the fineness of the glaze slurry is less than 0.5% when it passes through a 325-mesh sieve. After aging, the basic enamel glaze slurry is obtained.

[0036] (3) Preparation of enamel glaze based on transient template in-situ reaction

[0037] The core-shell structured functional precursor is added to the basic enamel glaze slurry and stirred until evenly dispersed to obtain the final product.

[0038] The additives are suspending agents and electrolytes.

[0039] The suspending agent is ultrafine clay, and the electrolyte is sodium nitrite.

[0040] The mass ratio of the enamel frit, suspending agent, electrolyte, and water is 100:(5~7):(0.35~0.45):(40~50).

[0041] The application of enamel glaze based on transient template in-situ reaction described in this invention involves applying the enamel glaze to the surface of a substrate, baking until the coating is dry, firing at a higher temperature, and cooling to obtain the finished enamel product.

[0042] The heating and firing process involves heating the temperature to 860-900°C.

[0043] During the firing process, the base glaze melts, and at the same time, the composite oxide shell on the surface of the core-shell precursor reacts in situ with the surrounding glass melt and the internal Si3N4 core to form a strong chemical bond interface; finally, it is cooled to room temperature to obtain the finished enamel product.

[0044] The core mechanism of this invention lies in the final firing stage, where a series of precise and controllable in-situ interfacial chemical reactions are initiated in the liquid glass matrix using core-shell structured functional precursors as micro-reaction units. The specific process is as follows:

[0045] After glazing and drying, the core-shell functional precursors, acting as independent and undisturbed micro-reaction units, are uniformly dispersed within the solid base enamel powder in the dry glaze layer before firing in the furnace. The crucial shell layer is a Y-Zr-Ti composite oxide prepared by homogeneous urea precipitation and calcined at 550–600℃. This shell layer exists in a high-free-energy, thermodynamically metastable structure, filled with numerous lattice defects and dangling bonds, exhibiting extremely high chemical reactivity.

[0046] When the firing temperature reaches the melting point of the enamel, the base enamel frit melts, forming a low-viscosity liquid silicate glass. This molten glass rapidly wets and surrounds the suspended precursor particles, creating ideal liquid-solid contact conditions for interfacial reactions.

[0047] In-situ reaction of "transient template":

[0048] The highly reactive Y-Zr-Ti composite oxide shell now acts as a "transient reaction template," with intense chemical reactions occurring simultaneously at both the inner and outer interfaces:

[0049] The shell-glass interface to the outside: the metastable structure of the outer surface of the shell breaks down the instant it comes into contact with the liquid glass, releasing highly reactive Zr. 4+ Ti 4+ Y 3+Ions rapidly diffuse and migrate into the glass melt, reacting chemically with the silicon-oxygen tetrahedral network to form stable covalent / ionic mixed bonds such as Si-O-Zr, Si-O-Ti, and Al-OY. This is equivalent to firmly "anchoring" the shell to the glass matrix network.

[0050] Internal shell-core interface: Simultaneously, the inner surface of the shell also undergoes a solid-phase reaction with the Si3N4 core. Driven by high temperature, the Ti in the shell... 4+ Highly reactive elements can interact with the Si-N bonds on the Si3N4 surface to form new interfacial phases such as Si-N-Ti or even TiN. These new phases have excellent lattice matching and bonding with the Si3N4 core.

[0051] Final structure formed:

[0052] As the reaction proceeds, the original, clearly defined "shell" structure disappears. In its place, it transforms in situ into a continuous, seamless gradient transition layer, from the Si3N4 core to the Ti / N-rich interface phase, then to the Zr / Y-rich gradient layer, and finally to the glass matrix. This gradient layer firmly "welds" the originally physically and chemically dissimilar and incompatible nitride ceramic core and silicate glass matrix together at the molecular scale, forming a powerful, integrated microscopic reinforcing unit.

[0053] This invention completely abandons the weak interfaces that rely solely on mechanical locking and van der Waals forces in traditional physical blending. By generating strong chemical bonds such as Si-O-Zr and Si-N-Ti in situ, the interfacial bonding force is elevated to an unprecedented level. During the impact process, energy can be effectively transferred to the high-strength Si3N4 core through the strong interface and absorbed, instead of premature dissociation at the weak interface as in traditional technology, which leads to catastrophic damage to the coating.

[0054] In weak interface systems, the toughening mechanisms of the reinforcement (crack deflection, crack bridging) cannot be effectively utilized due to premature interface failure. The "molecular welding layer" of this invention acts like a robust "drive shaft," synergistically activating and maximizing the various toughening mechanisms of Si3N4 particles. When microcracks propagate to the interface within the coating, they are forcibly deflected and passivated by the strong interface, or effectively bridged by the firmly bonded Si3N4 particles, thereby consuming a large amount of fracture energy and preventing further crack propagation.

[0055] The agglomeration problem in traditional physical blending leads to highly unstable product performance and numerous defects. This invention's innovative process route—preparing the glaze slurry first, then adding the precursor—fundamentally solves this problem. Each core-shell precursor is an independently dispersed micro-reaction unit, ensuring that these "welded" reinforcing points are uniformly and diffusely distributed in the final coating. This endows the final product with extremely high performance uniformity and reliability, laying a solid foundation for the large-scale industrial application of this high-performance enamel under harsh operating conditions.

[0056] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0057] (1) This invention achieves a truly strong chemical bond interface by using a highly reactive oxide shell as a "solder" in the final firing stage to build strong chemical bonds in situ between the reinforcing phase and the glass matrix. This fundamentally solves the problem of weak interfaces in traditional physical blending, allowing stress to be effectively transferred from the matrix to the high-strength reinforcing phase.

[0058] (2) This invention perfectly protects the integrity of the reinforcing unit and revolutionarily changes the process route by adding the precise core-shell precursor only after the glaze slurry is prepared, and using a low-energy mixing method, completely avoiding the damage to the reinforcing unit caused by traditional high-energy ball milling. This ensures that each Si3N4 particle can play its "in-situ welding" role as designed, ensuring the high stability and repeatability of the final product performance.

[0059] (3) This invention maximizes the synergistic enhancement effect. It is precisely because of the presence of the strong interface that the various mechanisms of Si3N4 core, such as load-bearing enhancement, crack deflection toughening, and micro-area compressive stress toughening, can be fully activated and work synergistically. The final product achieves a simultaneous and significant improvement in hardness, peel resistance, wear resistance, porosity, and acid and alkali resistance, and its comprehensive performance far exceeds that of the prior art. Detailed Implementation

[0060] The present invention will be further described below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.

[0061] Unless otherwise specified, all raw materials used in the examples were commercially available.

[0062] The ultrafine clay is 5000 mesh kaolin.

[0063] Example 1

[0064] Preparation of core-shell functional precursors

[0065] a. Activation of the nucleus surface

[0066] α-Si3N4 micropowder with an average particle size of 0.5 μm was added to a 25 wt.% hydrogen peroxide solution, and the mixture was heated to 80 °C and stirred for 4 h to induce surface hydroxylation. After the reaction, the mixture was filtered, and the filter cake was repeatedly washed with a large amount of deionized water until the pH of the washing solution was neutral. The washed powder was then dried in an oven at 130 °C for 6 h to obtain a silicon nitride core with surface hydroxyl activation.

[0067] b. Homogeneous precipitation coating

[0068] 62 kg of surface-hydroxyl-activated silicon nitride cores and 130 kg of urea were dispersed in 1500 L of deionized water and stirred for 30 min to form a homogeneous suspension. 43 kg of zirconium oxychloride (ZrOCl2·8H2O) and 12.3 kg of yttrium nitrate (Y(NO3)3·6H2O) were dissolved in 200 L of water, and 34.8 kg of titanium tetrachloride (TiCl4) was dissolved in 100 L of 7 wt.% dilute hydrochloric acid. The two salt solutions were then slowly added dropwise to the silicon nitride suspension. The mixed suspension was transferred to a reactor, stirred at 300 rpm, and heated to 90 °C, maintaining the temperature for 7 h. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered and washed five times with deionized water to remove residual ions.

[0069] c. Drying and low-temperature calcination

[0070] The washed powder was vacuum dried at 70℃ for 20 h. The dried powder was then placed in a muffle furnace and heated to 575±25℃ at a rate of 5℃ / min under air atmosphere, and held at that temperature for 1.5 h. After the holding period, the powder was allowed to cool naturally to room temperature with the furnace, and the resulting powder was the core-shell functional precursor powder. Based on the calculated feed amount, the core of the core-shell functional precursor comprised 62% of the total mass, and the shell comprised 38% of the total mass, with a ZrO2:TiO2:Y2O3 molar ratio of 0.65:0.35:0.03.

[0071] The method for preparing enamel glaze based on transient template in-situ reaction includes the following steps:

[0072] (1) Preparation of basic enamel frit

[0073] The basic enamel frit raw materials are: 40 kg of quartz powder, 20 kg of anhydrous boron oxide, 25.65 kg of soda ash, 7.34 kg of potassium carbonate, 6.17 kg of lithium carbonate, 2 kg of alumina powder, 1.79 kg of calcium carbonate, 0.5 kg of cobalt oxide, and 0.5 kg of nickel oxide. The mixture is heated to 1225±25℃ at a rate of 10℃ / min and melted for 100 min. After melting, the resulting glass melt is poured into water for water quenching to obtain fragmented enamel frit.

[0074] (2) Preparation of basic enamel glaze slurry

[0075] After drying 100 parts by weight of enamel frit, it is placed in a ball mill with 5 parts by weight of ultrafine clay, 0.45 parts by weight of sodium nitrite and 50 parts by weight of water until the fineness of the enamel slurry is less than 0.5% when passing through a 325-mesh sieve. After aging, the basic enamel slurry is obtained.

[0076] (3) Preparation of enamel glaze based on transient template in-situ reaction

[0077] The core-shell structured functional precursor is added to the basic enamel glaze slurry and stirred until evenly dispersed to obtain the final product.

[0078] The mixing mass ratio of the basic enamel frit and the core-shell structure functional precursor in the basic enamel slurry is 100:5.

[0079] The application of the enamel glaze based on transient template in-situ reaction involves applying the enamel glaze to the surface of the substrate to a depth of 80 μm using a spray gun, baking at 150°C until the coating is dry, heating to 880±20°C for firing, and cooling to obtain the finished enamel product.

[0080] Example 2

[0081] Preparation of core-shell functional precursors

[0082] a. Activation of the nucleus surface

[0083] α-Si3N4 micropowder with an average particle size of 5 μm was added to a 25 wt.% hydrogen peroxide solution, and the mixture was heated to 80 °C and stirred for 4 h to induce surface hydroxylation. After the reaction, the mixture was filtered, and the filter cake was repeatedly washed with a large amount of deionized water until the pH of the washing solution was neutral. The washed powder was then dried in an oven at 130 °C for 10 h to obtain a silicon nitride core with surface hydroxyl activation.

[0084] b. Homogeneous precipitation coating

[0085] 60 kg of surface-hydroxyl-activated silicon nitride cores and 150 kg of urea were dispersed in 1500 L of deionized water and stirred for 30 min to form a homogeneous suspension. 76.7 kg of zirconium oxychloride (ZrOCl2·8H2O) and 5.4 kg of yttrium nitrate (Y(NO3)3·6H2O) were dissolved in 200 L of water, and 6.5 kg of titanium tetrachloride (TiCl4) was dissolved in 100 L of 7 wt.% dilute hydrochloric acid. These two salt solutions were then slowly added dropwise to the silicon nitride suspension. The mixed suspension was transferred to a reactor, stirred at 300 rpm, and heated to 90 °C, maintaining the temperature for 7 h. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered and washed five times with deionized water to remove residual ions.

[0086] c. Drying and low-temperature calcination

[0087] The washed powder was vacuum dried at 75℃ for 20 hours. The dried powder was then placed in a muffle furnace and heated to 575±25℃ at a rate of 5℃ / min under air atmosphere, and held at that temperature for 2.5 hours. After holding, the powder was allowed to cool naturally to room temperature in the furnace, and the resulting powder was the core-shell functional precursor powder. Based on the calculated feed amount, the core of the core-shell functional precursor comprised 60% of the total mass, and the shell comprised 40%, with a ZrO2:TiO2:Y2O3 molar ratio of 0.90:0.1:0.08.

[0088] The method for preparing enamel glaze based on transient template in-situ reaction includes the following steps:

[0089] (1) Preparation of basic enamel frit

[0090] The basic enamel frit raw materials are: 55 kg of quartz powder, 14 kg of anhydrous boron oxide, 13.68 kg of soda ash, 1.47 kg of potassium carbonate, 1.23 kg of lithium carbonate, 8 kg of alumina powder, 10.72 kg of calcium carbonate, 1.5 kg of cobalt oxide, and 1.5 kg of nickel oxide. The mixture is heated to 1225±25℃ at a rate of 10℃ / min and melted for 100 min. After melting, the resulting glass melt is poured into water for water quenching to obtain fragmented enamel frit.

[0091] (2) Preparation of basic enamel glaze slurry

[0092] After drying 100 parts by weight of enamel frit, it is placed in a ball mill with 7 parts by weight of ultrafine clay, 0.35 parts by weight of sodium nitrite and 40 parts by weight of water until the fineness of the enamel slurry is less than 0.5% when passing through a 325-mesh sieve. After aging, the basic enamel slurry is obtained.

[0093] (3) Preparation of enamel glaze based on transient template in-situ reaction

[0094] The core-shell structured functional precursor is added to the basic enamel glaze slurry and stirred until evenly dispersed to obtain the final product.

[0095] The mixing mass ratio of the basic enamel frit and the core-shell structure functional precursor in the basic enamel slurry is 100:25.

[0096] The application of the enamel glaze based on transient template in-situ reaction involves applying the enamel glaze to the surface of the substrate to a depth of 80 μm using a spray gun, baking at 150°C until the coating is dry, heating to 880±20°C for firing, and cooling to obtain the finished enamel product.

[0097] Example 3

[0098] Preparation of core-shell functional precursors

[0099] a. Activation of the nucleus surface

[0100] α-Si3N4 micropowder with an average particle size of 1 μm was added to a 25 wt.% hydrogen peroxide solution, and the mixture was heated to 80 °C and stirred for 4 h to induce surface hydroxylation. After the reaction, the mixture was filtered, and the filter cake was repeatedly washed with a large amount of deionized water until the pH of the washing solution was neutral. The washed powder was then dried in an oven at 130 °C for 8 h to obtain a silicon nitride core with surface hydroxyl activation.

[0101] b. Homogeneous precipitation coating

[0102] 61 kg of surface-hydroxyl-activated silicon nitride cores and 140 kg of urea were dispersed in 1500 L of deionized water and stirred for 30 min to form a homogeneous suspension. 65 kg of zirconium oxychloride (ZrOCl2·8H2O) and 10.5 kg of yttrium nitrate (Y(NO3)3·6H2O) were dissolved in 200 L of water, and 13.1 kg of titanium tetrachloride (TiCl4) was dissolved in 100 L of 7 wt.% dilute hydrochloric acid. These two salt solutions were then slowly added dropwise to the silicon nitride suspension. The mixed suspension was transferred to a reactor, stirred at 300 rpm, and heated to 90 °C, maintaining the temperature for 7 h. After the reaction, the mixture was allowed to cool naturally to room temperature. The product was filtered and washed five times with deionized water to remove residual ions.

[0103] c. Drying and low-temperature calcination

[0104] The washed powder was vacuum dried at 72℃ for 20 h. The dried powder was then placed in a muffle furnace and heated to 575±25℃ at a rate of 5℃ / min under air atmosphere, and held at that temperature for 2.0 h. After the holding period, the powder was allowed to cool naturally to room temperature with the furnace, and the resulting powder was the core-shell functional precursor powder. Based on the calculated feed amount, the core of the core-shell functional precursor comprised 61% of the total mass, and the shell comprised 39% of the total mass, with a ZrO2:TiO2:Y2O3 molar ratio of 0.75:0.20:0.05.

[0105] The method for preparing enamel glaze based on transient template in-situ reaction includes the following steps:

[0106] (1) Preparation of basic enamel frit

[0107] The basic enamel frit raw materials are: 48 kg of quartz powder, 17 kg of anhydrous boron oxide, 20.52 kg of soda ash, 4.4 kg of potassium carbonate, 3.7 kg of lithium carbonate, 5 kg of alumina powder, 5.36 kg of calcium carbonate, 1 kg of cobalt oxide, and 1 kg of nickel oxide. The mixture is heated to 1225±25℃ at a rate of 10℃ / min and melted for 100 min. After melting, the resulting glass melt is poured into water for water quenching to obtain fragmented enamel frit.

[0108] (2) Preparation of basic enamel glaze slurry

[0109] After drying 100 parts by weight of enamel frit, it is placed in a ball mill with 6 parts by weight of ultrafine clay, 0.4 parts by weight of sodium nitrite and 45 parts by weight of water until the fineness of the enamel slurry is less than 0.5% when passing through a 325-mesh sieve. After aging, the basic enamel slurry is obtained.

[0110] (3) Preparation of enamel glaze based on transient template in-situ reaction

[0111] The core-shell structured functional precursor is added to the basic enamel glaze slurry and stirred until evenly dispersed to obtain the final product.

[0112] The mixing mass ratio of the basic enamel frit and the core-shell structure functional precursor in the basic enamel slurry is 100:15.

[0113] The application of the enamel glaze based on transient template in-situ reaction involves applying the enamel glaze to the surface of the substrate to a depth of 80 μm using a spray gun, baking at 150°C until the coating is dry, heating to 880±20°C for firing, and cooling to obtain the finished enamel product.

[0114] Comparative Example 1

[0115] Similar to Example 3, except that in step (3), instead of adding a core-shell structured functional precursor, 9.15 parts by mass of α-Si3N4 micro powder with an average particle size of 1 μm is added to ensure that the content of α-Si3N4 micro powder in the enamel glaze is the same as that in Example 3.

[0116] Comparative Example 2

[0117] Similar to Example 3, except that the core-shell structure functional precursor is added in step (1), melted together with the basic enamel frit raw material, and then ball-milled to obtain enamel glaze.

[0118] After the core-shell structured functional precursor is melted at high temperature, although protected by the shell, some α-Si3N4 will be oxidized or react with the molten glass to decompose, which will lead to the consumption of the reinforcing phase itself and weaken the reinforcing effect. At the same time, the intense mechanical force of the subsequent ball milling step may crush the already formed, precisely structured micron-sized reinforcing units and destroy their ideal interface structure with the matrix.

[0119] Performance testing:

[0120] The glazes of Examples 1-3 and Comparative Examples 1-2 were electrostatically sprayed onto both sides of a steel plate, with the coating thickness controlled at 80 μm, to obtain a sprayed plate. The plate was baked at 150°C until the coating was dry, then heated to 880±20°C for firing, and finally quenched in room temperature water for 5 minutes to obtain the test object.

[0121] The hardness test was performed using the Vickers microhardness test method.

[0122] Wear test: The tribological properties of the enamel surface were determined using an MG-2000 tribological testing machine under oil lubrication conditions. The sample size was 10mm×10mm×14mm, the friction load was 80N, the friction time was 60min, and the wear amount was measured.

[0123] Peelability test: A peel test is conducted using cellophane tape to observe the enamel peeling condition. Scoring is based on the following criteria: Excellent, no peeling: 10-9 points; Good, slight peeling: 9-8 points; Average, peeling area 1-10%: 8-7 points; Poor, peeling area greater than 10%: 7-6 points.

[0124] Adhesion test: The porosity was tested using metallographic methods.

[0125] Acid resistance testing was conducted according to GB / T / 9989-2005 standard: the glazes in Examples 1-3 and Comparative Examples 1-2 were coated on the ceramic surface, dried, fired, and cooled, and then boiled in a 20wt.% hydrochloric acid solution for 48 hours, and the acid corrosion loss was measured.

[0126] Alkali resistance was tested according to GB / 7989-2003 standard: the glazes in Examples 1-3 and Comparative Examples 1-2 were coated on the ceramic surface, dried, fired and cooled, and then placed in a 1 mol / L sodium hydroxide solution at 80°C for 48 hours, and the alkali corrosion loss was measured.

[0127] The experimental results are shown in Table 1 below:

[0128] Table 1. Results of glaze performance testing in Examples 1-3 and Comparative Examples 1-2

[0129] Test Project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Vickers hardness (GPa) 7.85 9.36 8.98 6.15 5.05 Wear amount (mg) 2.5 0.7 1.4 9.8 8.2 Peelability test (score / 10) 9.7 9.9 9.8 6.8 7.6 Adhesion (porosity, %) 0.35 0.16 0.25 1.15 0.55 <![CDATA[Acid resistance (weight loss, g / m 2 ·d)]]> 4.61 2.15 3.02 7.75 7.44 <![CDATA[Alkaline resistance (weight loss, g / m 2 ·d)]]> 6.05 3.58 4.31 9.12 8.75

[0130] Examples 1-3 of this invention outperform Comparative Example 1 (representing traditional physical blending technology) and Comparative Example 2 (representing an erroneous process) in all key performance indicators. The principle is that this invention constructs a strong chemically bonded interface between the Si3N4 core and the glass matrix through a "transient template in-situ reaction," forming a dense, overall reinforced structure. In contrast, Comparative Example 1 suffers from weak bonding and high porosity due to physical contact at the interface, while Comparative Example 2 suffers from the destruction of the reinforcing phase structure due to high-temperature melting; both examples exhibit fundamental defects.

[0131] Example 3 exhibits higher Vickers hardness and peel strength than Comparative Examples 1 and 2, while its wear rate is significantly lower. The strong interface allows the high-hardness Si3N4 particles to effectively withstand external stress and activate toughening mechanisms such as crack deflection and bridging, synergistically improving the coating's hardness and toughness. Conversely, the weak interface in Comparative Example 1 causes the particles to be easily "pulled out" during wear and peel tests, failing to provide reinforcement.

[0132] The porosity of Example 3 is lower than that of Comparative Examples 1 and 2, thus significantly reducing its acid and alkali corrosion resistance rate. The principle is that the in-situ reaction promotes good wetting and densification at the interface, eliminating the interfacial micropores commonly found in traditional physical blends. The dense microstructure effectively prevents the penetration of corrosive media, while the stable oxides ZrO2, TiO2, and Y2O3 in the shell layer are integrated into the glass network, further enhancing the chemical inertness of the matrix itself.

Claims

1. An enamel glaze based on transient template in-situ reaction, characterized in that, It is composed of a basic enamel slurry and a core-shell structure functional precursor. The basic enamel slurry is an aqueous suspension prepared by mixing and grinding a basic enamel frit and an additive. The mixing mass ratio of the basic enamel frit and the core-shell structure functional precursor is 100:(5~25). The basic enamel frit is composed of the following parts by weight of raw materials: SiO2: 40-55 parts; B2O3: 14-20 parts; Na2O: 8-15 parts; K2O: 1-5 parts; Li2O: 0.5~2.5 parts; Al2O3: 2-8 parts; CaO: 1-6 parts; CoO: 0.5~1.5 parts; NiO: 0.5~1.5 parts; The core-shell structured functional precursor is an inorganic composite powder whose original structure is: silicon nitride micron particles as the core, and a layer of Y-Zr-Ti composite oxide as the shell.

2. The enamel glaze based on transient template in-situ reaction according to claim 1, characterized in that, The molar ratio of the Y-Zr-Ti composite oxide is ZrO2:TiO2:Y2O3 = (0.6~0.9):(0.1~0.4):(0.03~0.08).

3. The enamel glaze based on transient template in-situ reaction according to claim 2, characterized in that, The core-shell structured functional precursor has a core mass ratio of 60-62% and a shell mass ratio of 38-40%.

4. The enamel glaze based on transient template in-situ reaction according to claim 3, characterized in that, The preparation method of the core-shell structured functional precursor includes the following steps: a. Activation of the nucleus surface Silicon nitride micro powder was added to hydrogen peroxide solution, heated and stirred to carry out hydroxylation, filtered and washed until neutral, and then dried to obtain silicon nitride core with surface hydroxyl activated. b. Homogeneous precipitation coating The surface-hydroxyl-activated silicon nitride nuclei were dispersed with urea in water to form a suspension. Solutions of titanium salt, zirconium salt, and yttrium salt were added to the suspension, and the mixture was heated and stirred. Metal hydroxides were uniformly precipitated on the surface of the silicon nitride particles to form a coating layer. After the reaction was completed, the product was subjected to solid-liquid separation and washed with deionized water. c. Drying and low-temperature calcination The washed powder was vacuum dried at 70-75℃ for 20 hours. The dried powder was then placed in a muffle furnace, heated to 550-600℃, and kept at that temperature. After cooling, the core-shell structured functional precursor powder was obtained.

5. A method for preparing an enamel glaze based on transient template in-situ reaction as described in any one of claims 1 to 4, characterized in that, Includes the following steps: (1) Preparation of basic enamel frit The raw material for basic enamel frit is heated to 1200~1250℃ and melted. After melting, the resulting glass melt is poured into water for water quenching to obtain fragmented basic enamel frit. (2) Preparation of basic enamel glaze slurry After drying the basic enamel frit, it is mixed with additives and water, ground, and aged to obtain the basic enamel glaze slurry. (3) Preparation of enamel glaze based on transient template in-situ reaction The core-shell structured functional precursor is added to the basic enamel glaze slurry and stirred until evenly dispersed to obtain the final product.

6. The method for preparing enamel glaze based on transient template in-situ reaction according to claim 5, characterized in that, The additives are suspending agents and electrolytes.

7. The method for preparing enamel glaze based on transient template in-situ reaction according to claim 6, characterized in that, The suspending agent is ultrafine clay, and the electrolyte is sodium nitrite.

8. The method for preparing enamel glaze based on transient template in-situ reaction according to claim 7, characterized in that, The mixing mass ratio of the basic enamel frit, suspending agent, electrolyte, and water is 100:(5~7):(0.35~0.45):(40~50).

9. The application of an enamel glaze based on transient template in-situ reaction as described in any one of claims 1 to 4, characterized in that, Enamel glaze is applied to the surface of the substrate, baked until the coating is dry, heated and fired, and then cooled to obtain the finished enamel product.

10. The application of the enamel glaze based on transient template in-situ reaction according to claim 9, characterized in that, The heating and firing process involves heating the temperature to 860-900°C.