Acid and alkali resistant microcrystalline glass and preparation method thereof, and kitchen stove or kitchen appliance

Abstract

The present application belongs to the field of microcrystalline glass, and specifically relates to acid- and alkali-resistant microcrystalline glass and its preparation method, as well as kitchen stoves or kitchen appliances. The chemical composition of the microcrystalline glass includes, in molar percentage, SiO2: 69.5mol%~71.5mol%, Al2O3: 13mol%~14.2mol%, Li2O: 7.4mol%~8.8mol%, P2O5: 0.37mol%~0.55mol%, SnO2: 0.05mol%~0.15mol%, As2O3+Sb2O3+B2O3+F<0.1mol%, 1.65<(SiO2+Al2O3) / (100×P2O5)<2.2; based on the total mass of the crystals contained in the microcrystalline glass, the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is 1.2%~9.3%; it can improve the high-temperature melting processing performance and acid and alkali corrosion resistance, reduce thermal expansion, and improve the resistance to sudden changes in temperature.

Description

Technical Field

[0001] The present application belongs to the field of microcrystalline glass technology, and specifically relates to acid- and alkali-resistant microcrystalline glass and a preparation method thereof, as well as a kitchen stove or kitchen appliance. Background Art

[0002] Glass-ceramics, also known as glass ceramics, is a special glass material containing a large number of micro-nano crystals and a residual glass phase. LAS glass-ceramics, a key branch of glass-ceramics, has a crystalline phase primarily composed of Li2O-Al2O3-SiO2. It possesses unique properties such as low expansion, high strength, and high-temperature resistance. It can withstand sudden temperature fluctuations from 800°C to room temperature, and even from 850°C to room temperature. It also exhibits excellent impact resistance, reaching a spring hammer impact strength of 0.5J and a flexural strength exceeding 100 MPa, significantly stronger than ordinary glass. Therefore, LAS glass-ceramics is an ideal material for applications such as kitchen stovetops and home appliance panels.

[0003] However, the kitchen environment is extremely complex. Glass cover panels used for stovetops and kitchen appliances, in addition to meeting basic requirements such as resistance to thermal shock and mechanical impact, must also possess excellent resistance to acid and alkali corrosion. First, acidic substances are common substances encountered by stovetops and household appliances. Cooking ingredients and seasonings, such as vinegar and ketchup, contain a variety of acidic substances. During the cooking process, some acidic liquids or residues can easily splash onto the microcrystalline panel. Prolonged contact can damage the surface of the microcrystalline panel, forming various spots. Secondly, alkaline substances deserve more attention, especially during the post-cooking cleaning stage. For common scenarios such as cleaning residual objects such as oil and grease, hot alkaline detergents are most effective. Especially when the panel surface is adhered to charred substances due to long-term heating, strongly alkaline detergents are preferred, and the higher the detergent water temperature, the better the cleaning effect.

[0004] It's common knowledge in the field that glass-based materials, compared to metals, are more acid-resistant than alkali-resistant. While LAS glass-ceramics offer better acid and alkali resistance than standard glass, their resistance to heat is still insufficient. Hot, strongly alkaline solutions, in particular, can easily cause the surface of LAS glass-ceramics panels to become roughened, causing slight corrosion and loss of gloss. While these defects don't affect the safety of the glass-ceramic panel, they can compromise its appearance and significantly reduce the user experience.

[0005] The current microcrystalline glass has limited acid and alkali resistance, which makes it difficult to meet the requirements for use in kitchen stoves and household appliance panels.

[0006] It should be noted that this part of the content of this application only provides background technology related to this application, and does not necessarily constitute prior art or public knowledge. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defects of existing microcrystalline glass in that it has limited acid and alkali resistance and is difficult to meet the use requirements of kitchen stoves and household appliance panels. It provides acid and alkali resistant microcrystalline glass and its preparation method, as well as kitchen stoves or kitchen appliances, which have significantly improved acid and alkali resistance, can meet the use requirements of kitchen stoves and household appliance panels, and protect the appearance of the microcrystalline panel during use.

[0008] To achieve the above objectives, in a first aspect, the present application provides an acid- and alkali-resistant microcrystalline glass, the chemical composition of which, in molar percentage, includes SiO2: 69.5mol% to 71.5mol%, Al2O3: 13mol% to 14.2mol%, Li2O: 7.4mol% to 8.8mol%, P2O5: 0.37mol% to 0.55mol%, SnO2: 0.05mol% to 0.15mol%, As2O3+Sb2O3+B2O3+F<0.1mol%, 1.65<(SiO2+Al2O3) / (100×P2O5)<2.2;

[0009] Based on the total mass of the crystals contained in the glass-ceramics, the ratio of the mass content of the keatnetite solid solution to the mass content of the high quartz solid solution is 1.2% to 9.3%;

[0010] The glass-ceramic was tested for acid corrosion resistance, and the corrosion rate was ≤15mg / dm 2 The test conditions of the acid corrosion test include: the corrosion liquid is HCl solution with a concentration of 6 mol / L, and the corrosion is carried out under boiling conditions for 6 hours; the alkali corrosion test of the microcrystalline glass is carried out, and the corrosion amount is ≤175 mg / dm 2 The test conditions of the alkali corrosion resistance test include: the corrosion liquid is a solution of equal volumes of a 0.5 mol / L Na2CO3 solution and a 1 mol / L NaOH solution, and the corrosion is carried out for 3 hours under boiling conditions.

[0011] In some preferred embodiments, based on the total mass of crystals contained in the microcrystalline glass, the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is 2.5% to 8.2%. Further preferably, the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is 2.8% to 7.4%.

[0012] In some preferred embodiments, 1.75<(SiO2+Al2O3) / (100×P2O5)<2.2, and further preferably, 1.9<(SiO2+Al2O3) / (100×P2O5)<2.2.

[0013] In some preferred embodiments, its chemical composition, in terms of molar percentage, further comprises: 1.5<(CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O]<2.4.

[0014] Preferably, 1.6<(CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O]<2.4, and further preferably, 2<CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O]<2.4.

[0015] In some preferred embodiments, its chemical composition, in molar percentage, further includes: CaO: 0.05 mol% to 0.50 mol%, MgO: 0.90 mol% to 1.40 mol%, ZnO: 0.95 mol% to 1.45 mol%, SrO+BaO: 0.55 mol% to 0.80 mol%, K2O+Na2O: 0.6 mol% to 1.0 mol%.

[0016] In some preferred embodiments, the chemical composition thereof further comprises, in molar percentage, the following: 0.71<(TiO2+ZrO2) / (R2O+RO)<0.89, where R2O represents a monovalent alkali metal oxide except Li2O, and RO represents a divalent metal oxide.

[0017] Preferably, 0.73<(TiO2+ZrO2) / (R2O+RO)<0.87, and more preferably, 0.75<(TiO2+ZrO2) / (R2O+RO)<0.85.

[0018] In some preferred embodiments, the chemical composition thereof further comprises, in molar percentage, TiO2: 2.3 mol% to 2.65 mol%, ZrO2: 0.65 mol% to 0.95 mol%.

[0019] In a second aspect, the present invention provides a method for preparing acid- and alkali-resistant microcrystalline glass, comprising: preparing the components of the microcrystalline glass according to the first aspect, mixing and melting them, then forming them, and then growing crystals.

[0020] In a third aspect, the present invention provides a kitchen stove or kitchen appliance, which includes the microcrystalline glass described in the first aspect and / or the microcrystalline glass prepared by the preparation method described in the second aspect.

[0021] The inventors discovered that in LAS glass-ceramics, the crystalline phase has better resistance to acids and alkalis than the residual glass phase. What is even more surprising is that the acid-alkali corrosion behavior of hydrothermal quartz is quite different from that of high quartz. First of all, the two are quite different in crystal morphology. The grain size of high quartz solid solution is relatively small, mostly 20nm to 60nm. During high-temperature heat treatment, as the holding time is extended or the crystallization temperature is increased, the high quartz solid solution gradually transforms into a hydrothermal quartz solid solution. The process of crystal phase transformation is the process of crystal agglomeration and growth. As the fine grains aggregate, the specific surface area of ​​the crystal decreases and the crystal surface becomes more stable. In addition, during the crystal phase transformation, more silicon dioxide participates in crystallization. These factors lead to the fact that when it is at the solid-liquid interface in an acidic or alkaline solution, hydrothermal quartz has higher corrosion resistance. Therefore, properly promoting the precipitation of the hydrothermal quartz crystal phase is of great help in improving the acid and alkali resistance of LAS glass-ceramics.

[0022] However, the inventors also found that excessively high keatite crystal phase, on the contrary, caused great damage to the alkali resistance. This is because in the process of transformation from high quartz to keatite, as silicon dioxide further participates in crystallization, the unit cell structure undergoes essential changes. The high quartz solid solution is a hexagonal system (Hexagonal), and the unit cell parameters are approximately The hydrothermal quartz solid solution is orthorhombic, and the unit cell parameters are approximately The unit cell of the hydrothermal quartz solid solution is significantly larger. The stacking coefficient of the orthorhombic crystal system of the hydrothermal quartz is smaller than that of the hexagonal crystal system of the high quartz. Therefore, there is a fast migration channel for ions inside the hydrothermal quartz. The ion migration rate of the small radius cations of the hydrothermal quartz is significantly higher than that of the high quartz. - Under the action of , elements such as Li, Mg, and Zn in the microcrystalline glass are more likely to separate from the crystal phase and form precipitation in the external solution. The difference in ion concentration on both sides of the solid-liquid interface will cause the elements in the hydrothermal quartz to continuously precipitate into the external solution. This precipitation rate is significantly higher than that of high quartz crystals, which ultimately leads to a significant increase in the mass loss per unit surface.

[0023] In addition, as is well known to those skilled in the art, the thermal expansion coefficient of keatnet quartz is much higher than that of the high quartz crystal phase. An excessively high proportion of the keatnet quartz crystal phase will greatly damage the linear thermal expansion coefficient of the LAS glass-ceramics, and may easily cause problems such as plate explosion during heating, which should be avoided.

[0024] Based on the total mass of the crystals contained in the microcrystalline glass, the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is 1.2% to 9.3%, which can improve the acid and alkali resistance of the microcrystalline glass and maintain a low thermal expansion coefficient (CTE40-700℃<0.5ppm / ℃).

[0025] In LAS glass-ceramics, in addition to the crystal structure and composition affecting the acid and alkali resistance, various oxide components also play a vital role in the acid and alkali resistance of the glass-ceramics. Its role is reflected in two aspects: first, it affects the acid and alkali resistance of the residual glass phase; second, it affects the crystallization process. This changes the acid and alkali resistance of the LAS glass-ceramics. At the same time, the LAS glass-ceramics of the present invention are prepared by high-temperature melting, calendering and other processes, which limit the range of oxide selection. In terms of final use, the rigid constraints on general requirements such as low expansion and high strength also constitute necessary restrictions on the range of oxide selection.

[0026] SiO2 can improve the acid and alkali resistance of microcrystalline glass, but it has a high melting point and is difficult to melt. Al2O3 can also improve the acid and alkali resistance, but it will increase the viscosity of microcrystalline glass, which can easily lead to difficulties in high-temperature melting and too fast hardening during the rolling process. The addition of SiO2 and Al2O3 increases the difficulty of melting and forming while improving the acid and alkali resistance. The addition of P2O5 can reduce the high-temperature viscosity and increase the solubility of high-melting-point substances such as alumina and zirconia in the glass, avoiding defects such as raw materials and spots during high-temperature melting. However, it is easy to cause the acid and alkali resistance of microcrystalline glass to decrease. On the basis of SiO2 content of 69.5mol%~71.5mol%, Al2O3 content of 13mol%~14.2mol%, and P2O5 content of 0.37mol%~0.55mol%, 1.65<(SiO2+Al2O3) / (100×P2O5)<2.2 is made. While maintaining the viscosity of microcrystalline glass in a range suitable for high-temperature melting and molding processing, the acid and alkali resistance of microcrystalline glass is improved.

[0027] The glass-ceramics of the present invention has a SiO2 content of 69.5mol% to 71.5mol%, an Al2O3 content of 13mol% to 14.2mol%, a Li2O content of 7.4mol% to 8.8mol%, a P2O5 content of 0.37mol% to 0.55mol%, a SnO2 content of 0.05mol% to 0.15mol%, As2O3+Sb2O3+B2O3+F<0.1mol%, 1.65<(SiO2+Al2O3) / (100×P2O5)<2.2, and based on the total mass of the crystals contained in the glass-ceramics, the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is 1.2% to 9.3%. Through the synergistic effect of the above-mentioned multiple aspects, the acid and alkali corrosion resistance of the glass-ceramics can be improved while maintaining the high-temperature melting and processing performance of the glass-ceramics. The acid corrosion resistance test of the glass-ceramics shows that the corrosion amount is ≤15mg / dm 2 , conduct alkali corrosion resistance test on glass-ceramics, corrosion amount ≤175mg / dm 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is a crystal phase test diagram of the microcrystalline glass in Example 1.

[0030] Figure 2 The linear thermal expansion coefficient test curves of the glass-ceramics of the embodiments and comparative examples at 40°C-700°C. DETAILED DESCRIPTION

[0031] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0032] The inventors of the present invention have found that in the existing technology, the acid and alkali resistance of microcrystalline glass is limited. When used in occasions such as kitchen stoves and household appliance panels, it is easy to be damaged in appearance due to easy contact with acidic or alkaline seasonings or cleaning agents containing acidic or alkaline substances, which affects the user experience and makes it difficult to meet the usage requirements of kitchen stoves and household appliance panels.

[0033] In a first aspect, the present invention provides an acid- and alkali-resistant microcrystalline glass, the chemical composition of which, in molar percentage, includes SiO2: 69.5mol% to 71.5mol%, Al2O3: 13mol% to 14.2mol%, Li2O: 7.4mol% to 8.8mol%, P2O5: 0.37mol% to 0.55mol%, SnO2: 0.05mol% to 0.15mol%, As2O3+Sb2O3+B2O3+F<0.1mol%, 1.65<(SiO2+Al2O3) / (100×P2O5)<2.2;

[0034] Based on the total mass of the crystals contained in the glass-ceramics, the ratio of the mass content of the keatite solid solution to the mass content of the high quartz solid solution is 1.2% to 9.3%;

[0035] The glass-ceramic was tested for acid corrosion resistance, and the corrosion rate was ≤15mg / dm 2The test conditions of the acid corrosion test include: the corrosion liquid is HCl solution with a concentration of 6 mol / L, and the corrosion is carried out under boiling conditions for 6 hours; the alkali corrosion test of the microcrystalline glass is carried out, and the corrosion amount is ≤175 mg / dm 2 The test conditions of the alkali corrosion resistance test include: the corrosion liquid is a solution of equal volumes of a 0.5 mol / L Na2CO3 solution and a 1 mol / L NaOH solution, and the corrosion is carried out for 3 hours under boiling conditions.

[0036] The inventors found that the grains of high quartz solid solution are small, with a size of 20nm to 60nm. After the high quartz solid solution is transformed into the hydrothermal quartz solid solution, the crystals agglomerate and grow, the specific surface area decreases, and the crystal surface is more stable. The high quartz solid solution is a hexagonal crystal system with a unit cell parameter of approximately The hydrothermal quartz solid solution is orthorhombic, and the unit cell parameters are approximately The unit cell of the hydrothermal quartz solid solution is significantly larger. The stacking coefficient of the orthorhombic crystal system of the hydrothermal quartz is smaller than that of the hexagonal crystal system of the high quartz. There are fast migration channels of ions inside the hydrothermal quartz. The ion migration rate of the small radius cations of the hydrothermal quartz is significantly higher than that of the high quartz. In the alkaline solution OH - Under the action of , elements such as Li, Mg, and Zn in the glass-ceramics are more likely to separate from the crystal phase and form precipitation in the external solution. The difference in ion concentration on both sides of the solid-liquid interface will cause the elements in the hydrothermal quartz to continuously precipitate into the external solution. Properly increasing the content of hydrothermal quartz solid solution in the crystal can improve the acid and alkali resistance of the glass-ceramics. However, when the content of hydrothermal quartz solid solution is too high, it will reduce the acid and alkali resistance of the glass-ceramics. Based on the total mass of the crystals contained in the glass-ceramics, the ratio of the mass content of hydrothermal quartz solid solution to the mass content of high quartz solid solution is 1.2% to 9.3%, which can improve the acid and alkali resistance of the glass-ceramics. When the ratio is lower than 1.2%, the acid and alkali resistance of the glass-ceramics is affected due to the insufficient stability of the crystal surface. When the ratio is higher than 9.3%, the ion migration rate of the small-radius cations in the hydrothermal quartz is significantly higher than that of high quartz, which affects the alkali resistance of the glass-ceramics.

[0037] Li2O is a good fluxing agent. During the high-temperature melting process, it reduces high-temperature viscosity, promotes homogenization and clarification of the glass melt, and is also beneficial for high-temperature calendering. During the high-temperature crystallization process, Li2O can also lower the crystallization temperature of high quartz and hot quartz, promoting crystallization, thereby reducing the expansion coefficient of the microcrystalline glass. The present invention reduces the high-temperature viscosity, reduces the difficulty of high-temperature melting, inhibits damage to the forming rollers, and reduces the crystallization temperature by 7.4mol% to 8.8mol%. It can also reduce costs while preventing the formation of crystalline phases such as lithium disilicate, which increases the thermal expansion coefficient of the microcrystalline glass and fails to meet the requirements for thermal shock resistance. If the Li2O content is less than 7.4mol%, the microcrystalline glass will have too high a viscosity, resulting in difficulties such as melting difficulties, rapid damage to the rollers, and high crystallization temperatures, making industrial production difficult. If the Li2O content is higher than 8.8mol%, the production cost is uneconomical and the microcrystalline glass will easily fail to meet the requirements for thermal shock resistance.

[0038] SiO2 has a high melting point. A SiO2 content of 69.5-71.5 mol% can reduce melting difficulty while lowering the thermal expansion coefficient, improving the glass-ceramic's resistance to thermal shock and acid and alkali. A SiO2 content below 69.5 mol% affects the glass-ceramic's resistance to acid and alkali, as well as thermal shock. A SiO2 content above 71.5 mol% makes melting difficult due to its high melting point, increasing the difficulty of melting and processing the glass-ceramic.

[0039] The Al2O3 content is 13mol%-14.2mol%, which can improve the hardness and acid and alkali resistance of microcrystalline glass while reducing the viscosity of the glass liquid, reducing the difficulty of high-temperature melting, reducing bubbles in the glass liquid, inhibiting crystallization before rolling, preventing too rapid hardening during calendering, and inhibiting the formation of unfavorable crystal phases such as mullite during the high-temperature crystallization process, which leads to an increase in the thermal expansion coefficient. If the Al2O3 content is lower than 13mol%, the acid and alkali resistance of the microcrystalline glass will be affected. If the Al2O3 content is higher than 14.2mol%, it is easy to cause high viscosity, difficulty in high-temperature melting, and inability to remove bubbles; the calendering process will harden too quickly and it will not be possible to roll to the specified thickness, or there may be crystallization before rolling, resulting in warping, deformation of the flat plate, and rapid wear of the roller; the high-temperature crystallization process will form unfavorable crystal phases such as mullite, which leads to an increase in the thermal expansion coefficient.

[0040] A P2O5 content of 0.37 mol% to 0.55 mol% can reduce high-temperature viscosity, increase the solubility of high-melting-point materials such as alumina and zirconia in the glass, and prevent defects such as raw materials and specks during high-temperature melting. This improves the acid and alkali resistance of the glass-ceramic. A P2O5 content below 0.37 mol% can lead to high high-temperature viscosity and defects such as raw materials and specks during high-temperature melting. A P2O5 content above 0.55 mol% can affect acid and alkali resistance.

[0041] The content of SnO2 is 0.05mol% to 0.15mol%, which can promote the high-temperature elimination of bubbles in the microcrystalline glass while avoiding premature crystallization during the rolling process. If it is less than 0.05mol%, bubbles are likely to appear in the microcrystalline glass. If it is greater than 0.15mol%, premature crystallization is likely to occur during the rolling process.

[0042] B2O3 and F elements will increase the thermal expansion coefficient of microcrystalline glass and reduce its acid and alkali resistance. As2O3 and Sb2O3 are physiologically toxic. As2O3+Sb2O3+B2O3+F<0.1mol% can reduce the thermal expansion coefficient of microcrystalline glass, improve its acid and alkali resistance while reducing its physiological toxicity.

[0043] SiO2 can improve the acid and alkali resistance of microcrystalline glass, but it has a high melting point and is difficult to melt. Al2O3 can also improve the acid and alkali resistance, but it will increase the viscosity of microcrystalline glass, which can easily lead to difficulties in high-temperature melting and too fast hardening during the rolling process. The addition of SiO2 and Al2O3 increases the difficulty of melting and forming while improving the acid and alkali resistance. The addition of P2O5 can reduce the high-temperature viscosity and increase the solubility of high-melting-point substances such as alumina and zirconia in the glass, avoiding defects such as raw materials and spots during high-temperature melting. However, it is easy to cause the acid and alkali resistance of the microcrystalline glass to decrease. On the basis of SiO2 content of 69.5mol% to 71.5mol%, Al2O3 content of 13mol% to 14.2mol%, and P2O5 content of 0.37mol% to 0.55mol%, 1.65<(SiO2+Al2O3) / (100×P2O5)<2.2 can improve the acid and alkali corrosion resistance of the microcrystalline glass while maintaining the viscosity of the microcrystalline glass in a range suitable for high-temperature melting and forming processing. If the (SiO2+Al2O3) / (100×P2O5) of the present invention is greater than 2.2, it is easy to cause difficulties in high-temperature melting, bubbles cannot be eliminated, the calendering process hardens too quickly, and crystallization before rolling. If it is less than 1.65, it is easy to cause the problem of decreased acid and alkali resistance.

[0044] The chemical composition of the glass-ceramics of the present invention includes, by mole percentage, SiO2: 69.5 mol% to 71.5 mol%, Al2O3: 13 mol% to 14.2 mol%, Li2O: 7.4 mol% to 8.8 mol%, P2O5: 0.37 mol% to 0.55 mol%, SnO2: 0.05 mol% to 0.15 mol%, As2O3+Sb2O3+B2O3+F<0.1 mol%, and 1.65<(SiO2+Al2O3) / (100×P2O5). <2.2, based on the total mass of the crystals contained in the glass-ceramics, the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high-quartz solid solution is 1.2% to 9.3%. Through the interaction between the content of each oxide, the relationship between the content of SiO2+Al2O3 and P2O5, and the relationship between the content of the hydrothermal quartz solid solution and the content of the high-quartz solid solution, it is possible to simultaneously improve the high-temperature melting and processing performance of the glass-ceramics, improve the acid and alkali corrosion resistance of the glass-ceramics, reduce the thermal expansion of the glass-ceramics, and improve the resistance of the glass-ceramics to sudden changes in temperature. The glass-ceramics was tested for acid corrosion resistance, and the corrosion amount was ≤15mg / dm 2 , conduct alkali corrosion resistance test on glass-ceramics, corrosion amount ≤175mg / dm 2 Microcrystalline glass is used in kitchen stoves, household appliance panels and other occasions, and can meet the use requirements of kitchen stoves and household appliance panels.

[0045] The SiO2 content of the present invention is, for example, 69.5 mol%, 70 mol%, 70.5 mol%, 71 mol% and 71.5 mol%, the Al2O3 content is, for example, 13 mol%, 13.3 mol%, 13.6 mol%, 13.8 mol% and 14.2 mol%, the Li2O content is, for example, 7.4 mol%, 7.7 mol%, 8.1 mol%, 8.4 mol% and 8.8 mol%, and the P2O5 content is, for example, 0.37 mol%, 0.39 mol%, 0.43 mol%, 0.48 mol%, 0.5 1mol% and 0.55mol%, the SnO2 content is, for example, 0.05mol%, 0.07mol%, 0.09mol%, 0.11mol%, 0.13mol% and 0.15mol%, (SiO2+Al2O3) / (100×P2O5) is, for example, 1.65, 1.7, 1.8, 1.9, 2, 2.1 and 2.2, and the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is, for example, 1.2%, 2.5%, 3.5%, 4.5%, 5.5%, 6.5%, 7.5%, 8.5% and 9.3%.

[0046] The acid corrosion resistance test method of the present invention refers to GB / T 15728-2021 or DIN 121166-2001, and the alkali corrosion resistance test method refers to GB / T 6580-2021 or ISO 695-1991. The acid corrosion resistance formula H = (mass difference / surface area) / 2. That is, for the acid corrosion resistance test, half of the 6-hour corrosion resistance value is used as the corrosion resistance value. The alkali corrosion resistance formula ρ = mass difference / surface area. That is, for the alkali corrosion resistance test, the 3-hour corrosion resistance value is used as the corrosion resistance value.

[0047] In some preferred embodiments, based on the total mass of the crystals contained in the glass-ceramics, the ratio of the mass content of the keatite solid solution to the mass content of the high-quartz solid solution is 2.5% to 8.2%. More preferably, the ratio is 2.8% to 7.4%. This preferred embodiment further improves the acid and alkali resistance of the glass-ceramics.

[0048] In the present invention, based on the total mass of crystals contained in the glass-ceramics, the sum of the mass content of the keatite solid solution and the mass content of the high quartz solid solution is preferably greater than 95wt%.

[0049] In some preferred embodiments, 1.75 < (SiO2 + Al2O3) / (100 × P2O5) < 2.2, and more preferably, 1.9 < (SiO2 + Al2O3) / (100 × P2O5) < 2.2. This preferred solution is more conducive to maintaining the viscosity of the microcrystalline glass within a range suitable for high-temperature melting and molding processing while improving the microcrystalline glass's resistance to acid and alkali corrosion.

[0050] In some preferred embodiments, its chemical composition, in terms of molar percentage, further comprises: 1.5<(CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O]<2.4.

[0051] The present invention finds that LAS system microcrystalline glass can form β-quartz solid solution during the controllable crystallization process, which has unique low expansion characteristics. Alkali metals and alkaline earth metals play a fluxing role in the glass melting process, reducing the difficulty of glass-ceramic melting and improving the quality of the glass melt. However, during the high-temperature crystallization process, the effects of the two groups of elements are different. Although lithium oxide is an alkali metal element, it is the main component of the LAS microcrystalline glass phase. Alkali metal and alkaline earth metal elements other than lithium oxide will lead to an increase in the expansion coefficient of the microcrystalline glass. Among them, sodium oxide and potassium oxide, as network modifiers, can destroy Si-O bonds and break some bridging oxygen bonds, weakening the acid and alkali resistance of the glass. At the same time, during the crystallization process, they tend to be enriched in the residual glass phase. As their content increases, they have a greater impact on the increase in the expansion coefficient of the microcrystalline glass and the weakening of its acid and alkali resistance. Barium oxide is also enriched in the residual glass phase. As its content increases, it will also lead to deterioration of thermal vibration resistance and acid and alkali resistance. Uniquely, elements such as Ca, Mg, and Zn can dissolve in the β-quartz solid solution during the high-temperature crystallization process, increasing crystallinity. This has a smaller impact on the expansion coefficient than alkali metal elements such as Na and K, and helps maintain excellent acid and alkali resistance. (Ca, Mg, and Zn doping will slightly change the unit cell parameters, but the impact will not be significant.) The β-quartz solid solution formed by Zn has a lower expansion coefficient than the β-quartz solid solution formed by Mg. When the SiO2 content is 69.5mol% to 71.5mol%, the Al2O3 content is 13mol% to 14.2mol%, the Li2O content is 7.4mol% to 8.8mol%, the P2O5 content is 0.37mol% to 0.55mol%, the SnO2 content is 0.05mol% to 0.15mol%, the As2O3+Sb2O3+B2O3+F content is <0.1mol%, 1.65<(SiO2+Al2O3) / (100×P2O5)<2.2, based on the total mass of the crystals contained in the microcrystalline glass, the hydrothermal quartz solid solution On the basis that the ratio of the mass content of the bulk silicate to the mass content of the high quartz solid solution is 1.2% to 9.3%, (CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O] is not higher than 2.4, which is more conducive to improving the high-temperature meltability and reducing the difficulty of melting and forming the microcrystalline glass; (CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O] is not lower than 1.5, which is more conducive to reducing the thermal expansion coefficient of the microcrystalline glass and improving the resistance to sudden changes in temperature and acid and alkali.

[0052] (CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O] is, for example, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3 and 2.4.

[0053] Preferably, 1.6 < (CaO + 0.4 × MgO + 1.2 × ZnO) / [0.5 × (BaO + SrO) + 1 × Na2O + 0.2 × K2O] < 2.4, and further preferably, 2 < (CaO + 0.4 × MgO + 1.2 × ZnO) / [0.5 × (BaO + SrO) + 1 × Na2O + 0.2 × K2O] < 2.4. This preferred solution is more conducive to reducing the difficulty of glass-ceramics melting while lowering the thermal expansion coefficient of the glass-ceramics, improving its resistance to sudden thermal shock and acid and alkali resistance.

[0054] In some preferred embodiments, its chemical composition, in molar percentage, further includes: CaO: 0.05 mol% to 0.50 mol%, MgO: 0.90 mol% to 1.40 mol%, ZnO: 0.95 mol% to 1.45 mol%, SrO+BaO: 0.55 mol% to 0.80 mol%, K2O+Na2O: 0.6 mol% to 1.0 mol%.

[0055] A CaO content of no more than 0.50 mol% is beneficial for preventing accidental crystallization during the rolling process. A MgO content of no less than 0.90 mol% is beneficial for improving the high-temperature fluxing effect, inhibiting crystallization during the forming process, and reducing the heat treatment temperature of the crystallization process. MgO can be dissolved in high quartz or hot quartz, improving the crystallinity of the glass-ceramics, but significantly increasing the thermal expansion coefficient. A MgO content of no more than 1.4 mol% is beneficial for reducing the thermal expansion coefficient of the glass-ceramics. A ZnO content of no less than 0.95 mol% is beneficial for reducing the viscosity of the glass-ceramics, inhibiting crystallization during the forming process, lowering the melting temperature and crystallization temperature, and improving the crystallinity. ZnO can be dissolved in high quartz or hot quartz, improving the crystallinity but increasing the thermal expansion coefficient of the glass-ceramics. A ZnO content of no more than 1.45 mol% is beneficial for reducing the thermal expansion coefficient of the glass-ceramics. Oxides such as BaO, Na2O, and K2O assist in the high-temperature melting process of glass-ceramics, improving melting quality. However, during high-temperature crystallization, these three oxides accumulate in the residual glass phase, increasing the thermal expansion coefficient while reducing the glass-ceramics' acid and alkali resistance. A SrO+BaO content of no less than 0.55 mol% further improves the meltability of high-temperature glass, increases the refractive index of LAS glass-ceramics, and enhances its appearance and texture. A content of no more than 0.80 mol% further reduces the thermal expansion coefficient of the glass-ceramics, improves its resistance to thermal shock and acid and alkali resistance. A K2O+Na2O content of no less than 0.6 mol% further reduces the viscosity of the glass-ceramics, eases the difficulty of high-temperature melting and rolling forming, lowers the crystallization temperature, and improves the glass-ceramics' preparation capabilities. A content of no more than 1.0 mol% further reduces the thermal expansion coefficient of the glass-ceramics, improves its resistance to thermal shock and acid and alkali resistance. It is understandable that the calcium oxide content in different batches of ore raw materials will fluctuate significantly. When necessary, additional calcium carbonate minerals need to be added to maintain stable composition during the production process. Sodium oxide and potassium oxide are commonly present in mineral raw materials and can also be added in the form of potassium salts, sodium salts, etc. when necessary.

[0056] The CaO content of the present invention is, for example, 0.05 mol%, 0.1 mol%, 0.2 mol%, 0.3 mol%, 0.4 mol% and 0.5 mol%, the MgO content is, for example, 0.9 mol%, 1 mol%, 1.1 mol%, 1.2 mol%, 1.3 mol% and 1.4 mol%, the ZnO content is, for example, 0.95 mol%, 1.05 mol%, 1.15 mol%, 1.25 mol%, 1.35 mol% and 1.45 mol%, the SrO+BaO content is, for example, 0.55 mol%, 0.6 mol%, 0.7 mol% and 0.8 mol%, and the K2O+Na2O content is, for example, 0.6 mol%, 0.7 mol%, 0.8 mol%, 0.9 mol% and 1 mol%.

[0057] In some preferred embodiments, its chemical composition, in molar percentage, further includes: 0.71<(TiO2+ZrO2) / (R2O+RO)<0.89, R2O represents a monovalent alkali metal element oxide except Li2O, and RO represents a divalent metal element oxide, including Zn of Group IIA and Group IIB.

[0058] The crystalline phase of glass-ceramics possesses greater resistance to acid and alkali corrosion than the glass phase. Increasing the combined content of the nucleating agents TiO2 and ZrO2 promotes crystallization, but excessively high nucleating agent content can reduce the flux content or glass skeleton content. A reduced flux content can lead to refractory glass, increased bubbles, and uneven melting, resulting in lower product quality or a sharp increase in production costs. A reduced glass skeleton composition can also reduce acid and alkali resistance. Excessively low combined TiO2 and ZrO2 contents can result in excessively high crystallization activation energy, reduced crystallization efficiency, and decreased crystallinity, which can also weaken the glass-ceramics' acid and alkali resistance. Lithium oxide is the primary component of LAS-based glass-ceramics. R2O, which does not contain lithium oxide, is typically sodium oxide or potassium oxide, and can also include cesium oxide and rubidium oxide. RO, which is typically calcium oxide, magnesium oxide, zinc oxide, barium oxide, etc., can also include strontium oxide. By mutually constraining the total amount of nucleating agent and the total amount of flux, the content of (TiO2+ZrO2) / (R2O+RO) is not less than 0.71, which is more conducive to ensuring that the crystallization temperature of high quartz and hydrothermal quartz is at a reasonable operating temperature, and the crystallization efficiency is suitable for industrial production, thereby improving the crystallinity and the acid and alkali resistance of the microcrystalline glass. The content of (TiO2+ZrO2) / (R2O+RO) is not higher than 0.89, which is more conducive to reducing the difficulty of melting, improving the quality of the microcrystalline glass or reducing production costs, and improving the acid and alkali resistance of the microcrystalline glass. Examples of (TiO2+ZrO2) / (R2O+RO) are 0.71, 0.72, 0.74, 0.76, 0.78, 0.8, 0.83, 0.86 and 0.89.

[0059] Preferably, 0.73 < (TiO2 + ZrO2) / (R2O + RO) < 0.87, and further preferably, 0.75 < (TiO2 + ZrO2) / (R2O + RO) < 0.85. This preferred solution is more conducive to improving crystallization efficiency, increasing crystallinity, improving the acid and alkali resistance of microcrystalline glass, reducing melting difficulty, improving microcrystalline glass quality, or reducing production costs.

[0060] In some preferred embodiments, the chemical composition further comprises, by mole percentage, the following: TiO2: 2.3 mol% to 2.65 mol%, and ZrO2: 0.65 mol% to 0.95 mol%. TiO2 and ZrO2 are the main nucleating agents for LAS glass-ceramics. Compared with the use of titanium oxide or zirconium oxide alone, their combined use has a significant synergistic effect, which is more conducive to significantly reducing the crystallization temperature of LAS. A TiO2 content of not less than 2.3 mol% and not more than 2.65 mol% further enhances the synergistic efficiency of the nucleating agents, reduces the crystallization temperature, improves the crystallization efficiency, increases the crystallinity, and improves the acid and alkali resistance of the glass-ceramics. A ZrO2 content of not less than 0.65 mol% further enhances the synergistic efficiency of the nucleating agents, increases the crystallinity, and improves the acid and alkali resistance of the glass-ceramics. A ZrO2 content of not more than 0.95 mol% further enhances the resistance to devitrification during the high-temperature melting process. The TiO content of the present invention is, for example, 2.3 mol%, 2.35 mol%, 2.45 mol%, 2.55 mol%, and 2.65 mol%, and the ZrO2 content is, for example, 0.65 mol%, 0.7 mol%, 0.8 mol%, 0.9 mol%, and 0.95 mol%.

[0061] In a third aspect, the present invention provides a method for preparing acid- and alkali-resistant glass-ceramics, comprising: preparing the components of the glass-ceramics described in the first aspect, mixing and melting them, forming them, and then growing crystals. The glass-ceramics produced by this method have significantly improved acid and alkali resistance, meeting the requirements for use in kitchen stovetops and household appliance panels, and protecting the appearance of the glass-ceramics during use.

[0062] In a fourth aspect, the present invention provides a kitchen stove or kitchen appliance, which includes the microcrystalline glass described in the first aspect and / or the microcrystalline glass prepared by the preparation method described in the second aspect.

[0063] The embodiments of the present invention are described in detail below, which are exemplary and only used to explain the present invention, and are not to be construed as limiting the present invention.

[0064] Example 1

[0065] The composition of the glass-ceramics is shown in Table 1. The preparation method of the glass-ceramics includes preparing materials according to the components contained in Table 1, mixing and melting, rolling and solidifying to form flat glass, and growing crystals of the rolled and solidified glass. During the crystal growth process, the temperature is first raised from room temperature to 760°C, kept at this temperature for 20 minutes for nucleation, and then further raised to 920°C and kept at this temperature for 40 minutes for crystallization to obtain the glass-ceramics.

[0066] The crystal phase test of the glass-ceramic of Example 1 was carried out using a Bruker D8 Advance test equipment. The test method and calculation process were as follows: compare the measured spectrum with the PDF standard card, then match the intensity of the two, and calculate the content ratio using EVA software. The crystal phase test diagram of the glass-ceramic of Example 1 can be found in Figure 1 . Taking the total mass of the crystals contained in the glass-ceramics as a benchmark, the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is shown in Table 1. The glass-ceramics of Example 1 was subjected to acid and alkali corrosion resistance tests. The test results are shown in Table 1. The test conditions for the acid corrosion resistance test are that the corrosion liquid is a 6 mol / L HCl solution, and the corrosion is carried out under boiling conditions for 6 hours. The test conditions for the alkali corrosion resistance test are that the corrosion liquid is a solution of equal volumes of a 0.5 mol / L Na2CO3 solution and a 1 mol / L NaOH solution, and the corrosion is carried out under boiling conditions for 3 hours. The acid corrosion resistance test method of the present invention refers to GB / T15728-2021 or DIN 121166-2001, and the alkali corrosion resistance test method refers to GB / T 6580-2021 or ISO 695-1991. The acid erosion resistance formula is H = (mass difference / surface area) / 2. For acid erosion resistance testing, half of the 6-hour erosion resistance is used as the erosion resistance. The alkali erosion resistance formula is ρ = mass difference / surface area. For alkali erosion resistance testing, the 3-hour erosion resistance is used as the erosion resistance. The linear thermal expansion coefficient of the glass-ceramics of Example 1 was tested from 40°C to 700°C. The test results are shown in Table 1.

[0067] Example 2-17

[0068] The methods of Example 1 were respectively followed, except that the composition of the glass-ceramics and / or the crystallization process parameters were different, as shown in Table 1. Corresponding tests were also performed, and the test results are shown in Table 1.

[0069] Comparative Examples 1-4

[0070] The methods of Example 1 were respectively followed, except that the composition of the glass-ceramics and / or the crystallization process parameters were different, as shown in Table 2. Corresponding tests were also performed, and the test results are shown in Table 2.

[0071] The test curves of the linear thermal expansion coefficient of the glass-ceramics of Example 1, Example 13, Comparative Example 1 and Comparative Example 2 at 40°C-700°C are shown in FIG. Figure 2 .

[0072] Table 1

[0073]

[0074]

[0075]

[0076]

[0077]

[0078] Table 2

[0079]

[0080] Comparative Examples 1 to 17 and Comparative Examples 1 to 2 and 4, based on the total mass of the crystals contained in the microcrystalline glass, the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is 1.2% to 9.3%, which can improve the acid and alkali resistance of the microcrystalline glass; Comparative Examples 1 to 17 and Comparative Example 3, 1.65<(SiO2+Al2O3) / (100×P2O5)<2.2, which can improve the acid and alkali resistance of the microcrystalline glass.

[0081] Comparing Examples 1 to 10, 1.75 < (SiO2 + Al2O3) / (100 × P2O5) < 2.2, which is more conducive to improving the acid and alkali resistance of the glass-ceramics, and 1.9 < (SiO2 + Al2O3) / (100 × P2O5) < 2.2, which is further conducive to improving the acid and alkali resistance of the glass-ceramics. Comparing Examples 1 to 7 and Examples 11 to 12, 2 < CaO + 0.4 × MgO + 1.2 × ZnO) / [0.5 × (BaO + SrO) + 1 × Na2O + 0.2 × K2O] < 2.4, which is more conducive to reducing the thermal expansion coefficient of the glass-ceramics and improving the resistance to sudden changes in temperature and acid and alkali. Comparing Examples 1 to 7 with Examples 13 to 17, based on the total mass of the crystals contained in the microcrystalline glass, the ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is 2.5% to 8.2%, which is more conducive to improving the acid and alkali resistance of the microcrystalline glass.

Claims

1. An acid and alkali resistant glass-ceramic, characterized in that: Its chemical composition, in terms of molar percentage, includes SiO2: 69.5mol% to 71.5mol%, Al2O3: 13mol% to 14.2mol%, Li2O: 7.4mol% to 8.8mol%, P2O5: 0.37mol% to 0.55mol%, SnO2: 0.05mol% to 0.15mol%, As2O3+Sb2O3+B2O3+F<0.1mol%, 1.65<(SiO2+Al2O3) / (100×P2O5)<2.2; Based on the total mass of the crystals contained in the glass-ceramics, the ratio of the mass content of the keatnetite solid solution to the mass content of the high quartz solid solution is 1.2% to 9.3%; The glass-ceramic was tested for acid corrosion resistance, and the corrosion rate was ≤15mg / dm 2 The test conditions of the acid corrosion test include: the corrosion liquid is HCl solution with a concentration of 6 mol / L, and the corrosion is carried out under boiling conditions for 6 hours; the alkali corrosion test of the microcrystalline glass is carried out, and the corrosion amount is ≤175 mg / dm 2 The test conditions of the alkali corrosion resistance test include: the corrosion liquid is a solution of equal volumes of a 0.5 mol / L Na2CO3 solution and a 1 mol / L NaOH solution, and the corrosion is carried out under boiling conditions for 3 hours.

2. The glass-ceramic according to claim 1, characterized in that Taking the total mass of the crystals contained in the glass-ceramics as a benchmark, the ratio of the mass content of the keatnetite solid solution to the mass content of the high quartz solid solution is 2.5% to 8.2%.

3. The glass-ceramic according to claim 2, characterized in that: The ratio of the mass content of the hydrothermal quartz solid solution to the mass content of the high quartz solid solution is 2.8% to 7.4%.

4. The glass-ceramic according to claim 1, characterized in that 1.75<(SiO2+Al2O3) / (100×P2O5)<2.

2.

5. The glass-ceramic according to claim 4, characterized in that: 1.9<(SiO2+Al2O3) / (100×P2O5)<2.

2.

6. The glass-ceramic according to claim 1, characterized in that: Its chemical composition in terms of molar percentage also includes: 1.5<(CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O]<2.

4.

7. The glass-ceramics according to claim 6, characterized in that: 1.6<(CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O]<2.

4.

8. The glass-ceramics according to claim 7, characterized in that: 2<CaO+0.4×MgO+1.2×ZnO) / [0.5×(BaO+SrO)+1×Na2O+0.2×K2O]<2.

4.

9. The glass-ceramic according to claim 1, characterized in that: Its chemical composition, calculated in molar percentage, also includes: CaO: 0.05 mol% to 0.50 mol%, MgO: 0.90 mol% to 1.40 mol%, ZnO: 0.95 mol% to 1.45 mol%, SrO+BaO: 0.55 mol% to 0.80 mol%, K2O+Na2O: 0.6 mol% to 1.0 mol%.

10. The glass-ceramic according to claim 1, characterized in that: Its chemical composition, in terms of molar percentage, also includes: 0.71<(TiO2+ZrO2) / (R2O+RO)<0.89, R2O represents a monovalent alkali metal element oxide except Li2O, and RO represents a divalent metal element oxide.

11. The glass-ceramic according to claim 10, characterized in that: 0.73<(TiO2+ZrO2) / (R2O+RO)<0.

87.

12. The glass-ceramic according to claim 11, characterized in that: 0.75<(TiO2+ZrO2) / (R2O+RO)<0.

85.

13. The glass-ceramic according to claim 1, characterized in that: Its chemical composition, calculated in molar percentage, also includes: TiO2: 2.3 mol% to 2.65 mol%, ZrO2: 0.65 mol% to 0.95 mol%.

14. A method for preparing acid- and alkali-resistant glass-ceramics, characterized in that: include: The components of the glass-ceramics according to any one of claims 1 to 13 are mixed and melted, then formed, and then crystals are grown.

15. A kitchen stove or kitchen appliance, characterized in that: It includes the microcrystalline glass according to any one of claims 1 to 13 and / or the microcrystalline glass prepared by the preparation method according to claim 14.

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