Soft light physical coloring glaze, ceramic tile and preparation method of soft light physical coloring glaze

Abstract

The invention discloses soft-light physical coloring glaze, a ceramic tile and a preparation method of the soft-light physical coloring glaze. The soft-light physical coloring glaze is prepared from the following raw material components in parts by weight: 30 to 50 parts of calcium-zinc series low-temperature frit, 25 to 35 parts of silicon dioxide coated zinc oxide, 5 to 10 parts of titanium dioxide, 2 to 6 parts of zircon sand and 1 to 2 parts of phase splitting agent, wherein the calcium-zinc series low-temperature frit comprises the following chemical components in percentage by weight: 55 to 60 percent of SiO2, 5 to 10 percent of Al2O3, 10 to 15 percent of CaO, 1 to 3 percent of MgO, 5 to 8 percent of K2O, 1 to 2 percent of Na2O, 1 to 2 percent of BaO and 5 to 10 percent of ZnO. By controlling the components and process of the raw materials, the glaze melt is split into phases to form spherical liquid drops, and the size of the spherical liquid drops is smaller than or close to the wavelength of visible light, so that the glaze forms soft physical coloring which can change from blue opalescence to light pink opalescence.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building ceramics, and particularly relates to a soft light physical coloring glaze, a ceramic tile and a preparation method thereof. BACKGROUND

[0002] In the current building ceramic decoration field, the mainstream coloring method is mainly chemical color (pigment color), that is, the selective absorption of colorants or pigments in ink to light is used to realize coloration by inkjet printing technology. This method has strong controllability and is easy to realize the large-scale replication of products, but the coloration effect is single and lacks the flexibility of changing with light, which is difficult to meet the upgrading needs of consumers for personalized decoration effect of building ceramics.

[0003] Physical coloring technology (also known as structural coloration technology) has become an important research and development direction of building ceramic decoration technology because it does not rely on chemical colorants and only uses the selective reflection, scattering, interference or diffraction of the microstructure of the material to present color, has excellent color durability, is green and environmentally friendly, and is sensitive to light (such as goniochromaticity or iridescence), and has other significant advantages. Soft light brick refers to a ceramic tile whose surface reflection is between strong light and weak light, which achieves a comfortable degree of human visual perception and a decoration effect without light pollution by reducing the reflectivity.

[0004] At present, the performance and visual effect of physical coloring technology and traditional soft light ceramic tile products need to be further improved. The existing physical coloring technology mainly includes the following ways: first, physical coloring is achieved by depositing a photonic crystal film on the surface of the glaze layer of the building ceramic sintered body, and the periodic arrangement of the photonic crystal is used to achieve the coloration effect. However, the heat treatment temperature of the photonic crystal film layer in this method is relatively low (500-900℃), which easily leads to poor mechanical properties and durability of the film layer, and the secondary sintering heat treatment significantly increases the manufacturing cost of building ceramics and reduces the production efficiency, which is not conducive to industrialization. Second, a femtosecond laser device is used to finely process the glaze layer or coating film layer of the building ceramic, and physical coloring is achieved by constructing a periodic arrangement of micro-nano structures. However, this technology has extremely high requirements for equipment precision and operation, and the equipment investment cost is high, which makes it extremely difficult to apply in industrialization. Third, physical coloring is achieved by using the spectral response characteristics of the precipitated crystal phase through the formula and structure design of the ceramic glaze layer, but this method mostly relies on a large amount of rare earth metals or rare metal oxides (such as niobium oxide, cerium oxide, yttrium oxide, etc.), so the raw material cost is relatively high, which makes it difficult to achieve large-scale production and application. At the same time, traditional soft light bricks only have a single soft light texture and no special optical effect, which cannot meet the personalized decoration needs. If it relies on chemical colorants, it will have the problems of easy fading and poor durability, and the surface hardness of traditional soft light bricks is generally low, which greatly limits their application scenarios.

[0005] Therefore, it is urgent to develop a new ceramic glaze to realize the soft light and physical coloring composite decoration effect without using high-cost rare earth metals, and improve the mechanical properties and durability of the glaze surface. SUMMARY

[0006] The present application provides a soft light physical coloring glaze, ceramic tile and preparation method thereof to solve one or more technical problems in the prior art and at least provide a beneficial alternative or create conditions.

[0007] To solve the above technical problems, the first aspect of the present application provides a soft light physical coloring glaze, the raw material components of which include, by weight fraction: calcium-zinc low-temperature frit 30-50 parts, silica-coated zinc oxide 25-35 parts, titanium white 5-10 parts, zircon sand 2-6 parts, and phase separation agent 1-2 parts; the chemical composition of the calcium-zinc low-temperature frit includes, by weight percentage: SiO2 55-60%, Al2O3 5-10%, CaO 10-15%, MgO 1-3%, K2O 5-8%, Na2O 1-2%, BaO 1-2%, and ZnO 5-10%.

[0008] Specifically, the present application uses a semi-frit ceramic glaze composed of raw materials and frits, by adding a certain amount of silica-coated zinc oxide, titanium white, zircon sand and phase separation agent in the calcium-zinc low-temperature frit, controlling the components of each raw material, and preparing at a specific firing temperature, the glaze melt is phase-separated to form spherical droplets, and the droplet size is smaller than or similar to the wavelength of visible light, which produces Rayleigh scattering or diffraction of visible light, so that the glaze forms soft physical coloring, and the specific color is determined by the size of the phase-separated droplets, which can change between blue opalescent and light pink opalescent. At the same time, the formation of phase-separated droplets is beneficial to promote the precipitation of zinc silicate crystals in the glaze melt, thereby improving the mechanical properties of the glaze. In addition, by using silica-coated zinc oxide and controlling the reaction interface between zinc oxide and silica, the crystallization rate of zinc silicate crystals is slowed down, local rapid crystallization is avoided, and the soft light effect of the glaze is improved.

[0009] In some embodiments of the present application, the particle size of the silica-coated zinc oxide is 300-1800 nm; preferably 500-1000 nm.

[0010] In some embodiments of the present application, the preparation method of the silica-coated zinc oxide includes the following steps: (1) adding nano-ZnO and polyethylene glycol into a mixed solvent of anhydrous ethanol and deionized water, mixing to prepare solution A; the polyethylene glycol (molecular weight 6000-8000), the volume ratio of anhydrous ethanol and deionized water is (8-12):1, and the mass ratio of nano-ZnO to polyethylene glycol is (0.01-0.03):1; (2) adding ammonia water into the solution A, mixing to prepare solution B; (3) dissolving tetraethyl orthosilicate into ethanol to prepare solution C; the mass ratio of the nano-ZnO and the tetraethyl orthosilicate is 1:(1-10), and the volume ratio of the ammonia water and the tetraethyl orthosilicate is (0.01-5):(0.02-0.2); (4) adding the solution C into the solution B, ultrasonicating, centrifuging, collecting the solid, washing, drying to prepare the silica-coated zinc oxide.

[0011] In some embodiments of the present application, the phase separation agent is selected from at least one of calcium phosphate, calcium fluoride, sodium phosphate, P2O5 and F - The free enthalpy of forming the phase separation droplets can be reduced in the glaze melt, thereby promoting the formation of the phase separation droplets, and by controlling the size of the phase separation droplets, different color effects can be obtained.

[0012] The second aspect of the present application provides a soft light physically colored ceramic tile, which comprises, from bottom to top, a lower body layer, an upper body layer, a first bottom glaze layer, a second bottom glaze layer and a color glaze layer, and the color glaze layer is fired from the soft light physically colored glaze.

[0013] In some embodiments of the present application, the preparation raw material of the lower body layer is a basic body powder, and the chemical composition of the basic body powder comprises, in terms of percentage by weight, SiO2 65-70%, Al2O3 18-22%, Fe2O3 0.8-1.5%, TiO2 0.1-0.5%, CaO 0.5-2%, MgO 0.3-1.2%, K2O 1-3%, Na2O 0.8-2.5%, and loss on ignition 4-5.5%.

[0014] In some embodiments of the present application, the preparation raw material of the upper body layer comprises the basic body powder and anorthite, and the amount of the anorthite is 5-8% of the basic body powder.

[0015] In some embodiments of the present application, the thickness ratio of the lower body layer to the upper body layer is (10-15):1.

[0016] Specifically, the low-melting-point anorthite (with a melting temperature of 1050-1100℃) is introduced into the upper body layer, which can partially melt with the first bottom glaze at the initial stage of firing to form a “body-bottom glaze” transition layer, guide the ordered growth of zinc silicate crystallization from the interface to the interior of the glaze layer, and avoid local crystallization disorder, which is beneficial to improve the mechanical properties of the product.

[0017] In some embodiments of the present application, the chemical composition of the first bottom glaze layer includes, by weight percentage: SiO2 53-59%, Al2O3 26-30%, Fe2O3 0.2-0.5%, TiO2 0.1-0.2%, CaO 0.3-0.8%, MgO 0.1-0.5%, K2O 2-6%, Na2O 2-4%, ZrO2 4-8%, loss on ignition 2-5%.

[0018] Specifically, the first bottom glaze with low iron and high zirconium is conducive to inhibiting the migration of impurities such as Fe2O3 and TiO2 in the body to the glaze layer, and enhancing the densification of the bottom glaze. At the same time, the SiO2 and Al2O3 content in the first bottom glaze layer is similar to that of the upper body layer, which is conducive to ensuring the structural stability of the product; and the high Al2O3 content is conducive to improving the mechanical strength and high temperature resistance of the bottom glaze.

[0019] In some embodiments of the present application, the chemical composition of the second bottom glaze layer includes, by weight percentage: SiO2 60-65%, Al2O3 20-25%, Fe2O3 0.2-0.5%, TiO2 0.1-0.2%, CaO 0.3-0.8%, MgO 0.1-0.5%, K2O 2-6%, Na2O 2-4%, ZrO2 4-8%, ZnO 3-5%, loss on ignition 2-5%.

[0020] Specifically, the second bottom glaze layer forms a diffusion channel with the calcium-zinc system frit in the color glaze layer by adjusting the content of SiO2 and ZnO: during the firing process, the Zn 2+ can migrate along the composition gradient of the second bottom glaze layer to the "bottom glaze-color glaze" interface, and the diffusion rate is higher than that of the single-layer bottom glaze design; the migration process is controlled by the composition of the second bottom glaze layer, avoiding the local aggregation of Zn 2+ , and achieving uniform distribution. At the same time, the uniformly migrated Zn 2+ can preferentially react with SiO2 in the second bottom glaze layer and the color glaze at the "bottom glaze-color glaze" interface, promoting the nucleation of zinc silicate (Zn2SiO4) at the interface and orderly diffusing into the color glaze, avoiding problems such as crystallization aggregation and local crystallization disorder; and the high stability of the first bottom glaze layer can support the melting-crystallization process of the second bottom glaze layer and the color glaze, ensuring the structure of the entire glaze layer system after firing, and improving the mechanical properties of the product.

[0021] The third aspect of the present application provides a preparation method of the above-mentioned ceramic tile, comprising the following steps: (1) The powder for preparing the lower body layer and the upper body layer is sequentially laid in the mold, and is pressed and formed to obtain the lower body layer and the upper body layer; (2) The surface of the upper body layer is subjected to sandblasting treatment to form a micron-level concave-convex structure, and a surface-treated upper body layer is obtained. (3) sequentially applying a first base glaze, a second base glaze and a soft light physical color glaze on the surface of the surface-treated upper body layer to sequentially form a first base glaze layer, a second base glaze layer and a color glaze layer, and then drying and firing in a kiln to obtain the ceramic tile.

[0022] In some embodiments of the present application, in step (2), the sandblasting treatment uses 80-100 mesh corundum, the sandblasting pressure is 0.2-0.5 MPa, and the distance is 10-20 cm, so that the surface of the green tile forms a concave-convex structure of 5-10 μm. This structure can increase the contact area between the first base glaze and the upper body layer, reduce the interfacial stress, avoid the cracking of the glaze layer due to the difference in thermal expansion between the glaze layer and the body during firing, and ensure uniform distribution of zinc silicate crystallization at the interface.

[0023] In some embodiments of the present application, in step (3), the soft light physical color glaze is applied by multiple glazing, the number of glazing is not less than 3 times, the total glazing amount is 750-1050 g / m2, and the single glazing amount is controlled to be 250-350 g / m2.

[0024] Specifically, multiple glazing is beneficial to reduce the internal bubbles of the color glaze layer and improve the denseness of the glaze layer. In the traditional single glazing process, the glaze slurry is thick, the internal water evaporation path is long, and closed bubbles are easily formed, which leads to pinhole or bubble defects in the glaze layer after firing, affecting the uniform distribution of the phase-separated droplets. In the present application, multiple thin glazing is adopted, the thickness of each layer of glaze slurry is reduced compared with single thick glazing, the water evaporation path is shortened, and the free water and bound water in the glaze slurry can be fully escaped during the drying process of each layer, finally reducing the internal bubble rate of the effect glaze layer and significantly improving the denseness of the glaze layer, providing a defect-free glass matrix environment for the phase separation-crystallization process, and avoiding the interference of bubbles on the scattering effect of phase-separated droplets. At the same time, multiple glazing is beneficial to form a "crystallization gradient" and promote the uniform distribution of zinc silicate. Due to the influence of slight fluctuations in environmental humidity and temperature during the drying process of each thin glazing, the composition of each layer of glaze slurry will form a slight difference, which forms a composition gradient from the surface layer to the inner layer in the glaze layer after multiple thin glazing, and then converts into a crystallization gradient. The crystallization gradient can guide Zn 2+ and SiO2 in the effect glaze to gradually react to form zinc silicate along the gradient direction, avoiding the problem of zinc silicate agglomeration caused by local aggregation in the traditional single glazing. 2+ Therefore, the multiple glazing of the present application can improve the uniformity of zinc silicate crystallization in the glaze layer compared with single glazing, and ensure the uniform distribution of zinc silicate crystalline phase in the glaze layer, providing a uniform microstructure basis for the synergistic coloring of the zinc silicate opalescent effect and the scattering or diffraction of phase-separated droplets, and avoiding the color difference caused by uneven crystallization.

[0025] In some embodiments of the present invention, in step (3), the firing temperature regime is as follows: first, the temperature is raised to 1120-1150℃ at a rate of 3-5℃ / min and held for 20-30min; then the temperature is lowered by 5-10℃ and held for 5-10min; then the temperature is raised by 5-10℃ and held for 5-10min; the cooling and heating cycle is repeated more than 2 times; finally, water vapor with a volume fraction of 5-8% is introduced, and the temperature is lowered to 700-800℃ at a rate of 15-20℃ / min, then lowered to 500-600℃ at a rate of 5-10℃ / min, and finally discharged from the kiln and cooled naturally.

[0026] Specifically, this invention first raises the temperature to the maximum level at a rate of 3-5℃ / min, then employs a "constant temperature-micro-cooling cycle" to utilize temperature fluctuations to promote the rearrangement of amorphous phase molecules, resulting in a more regular, short-range ordered distribution of the phase-separated droplets. Next, a small amount of water vapor is introduced. Through the weak reaction between the water vapor and the glaze surface, a hydroxyl layer forms on the surface of the zinc silicate particles, enhancing the interparticle bonding force and preventing cracking of the crystallization layer caused by cooling stress; simultaneously, it inhibits the coarsening of the phase-separated droplets and controls their size. Finally, low-temperature annealing is performed to eliminate residual stress within the glaze layer through atomic diffusion, further consolidating the uniformity of zinc silicate crystallization and the short-range ordered structure of the phase-separated droplets, thus improving overall stability.

[0027] Compared with the prior art, the above-described technical solution of the present invention has at least the following technical effects or advantages: This invention employs a semi-fused ceramic glaze. By adding a certain amount of silica-coated zinc oxide, titanium dioxide, zircon sand, and a phase-separating agent to a calcium-zinc based low-temperature frit, and controlling the composition of each raw material, the glaze melt undergoes phase separation to form spherical droplets at a specific firing temperature. These droplets are made smaller than or close to the wavelength of visible light, resulting in Rayleigh scattering or diffraction of visible light. This produces a soft physical coloration in the glaze, varying between a blue opalescent and a pale pink opalescent sheen. Simultaneously, the formation of these phase-separated droplets promotes the precipitation of zinc silicate crystals in the glaze melt, thereby improving the mechanical properties of the glaze. The silica-coated zinc oxide slows down the crystallization rate of zinc silicate, preventing localized rapid crystallization and enhancing the soft-light effect of the glaze. Attached Figure Description

[0028] Figure 1 TEM image of the soft-light physical coloring glaze prepared in Example 1; Figure 2 SEM image of the soft-light physical coloring glaze prepared in Example 1; Figure 3 SEM image of the soft-light physical coloring glaze prepared in Comparative Example 6. Detailed Implementation

[0029] The present invention will now be described in detail with reference to embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention by those skilled in the art based on the above description should still fall within the scope of protection of the invention. Furthermore, all raw materials mentioned below, unless otherwise specified, are commercially available products; all process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art.

[0030] The preparation method of silica-coated zinc oxide used in the following examples and comparative examples is as follows: (1) Disperse 0.02g of nano ZnO and 0.9g of polyethylene glycol (molecular weight 8000) in 100mL of anhydrous ethanol, add 10mL of deionized water, and sonicate at 80W for 30min to obtain solution A; (2) Add 1 mL of ammonia water to solution A and continue sonication for 15 min to obtain solution B; (3) Dissolve 0.02 mL of tetraethyl orthosilicate in 25 mL of anhydrous ethanol to prepare solution C; (4) Add solution C to solution B, continue ultrasonic treatment for 2.5 h, centrifuge to separate, wash the solid repeatedly with anhydrous ethanol, and vacuum dry at 60 °C to obtain 500-1000 nm silica-coated zinc oxide.

[0031] Example 1 A soft-light physical coloring glaze comprises, by weight, 40 parts of calcium-zinc low-temperature frit, 30 parts of silica-coated zinc oxide, 7 parts of titanium dioxide, 4 parts of zircon sand, 0.5 parts of sodium phosphate, and 0.5 parts of calcium fluoride; the chemical composition of the calcium-zinc low-temperature frit, by weight percentage, comprises: 59% SiO2, 39% Al2O, 13% CaO, 2% MgO, 6% K2O, 1.5% Na2O, 1.5% BaO, and 8% ZnO.

[0032] A soft-light physically colored ceramic tile comprises, from bottom to top, a lower body layer, an upper body layer, a first base glaze layer, a second base glaze layer, and a colored glaze layer, wherein the colored glaze layer is fired from the aforementioned soft-light physically colored glaze.

[0033] The raw material for preparing the lower blank layer is a basic blank powder. The chemical composition of the basic blank powder, by weight percentage, includes: SiO2 67.8%, Al2O3 20%, Fe2O3 1.1%, TiO2 0.3%, CaO 1.2%, MgO 0.8%, K2O 2%, Na2O 1.5%, and loss on ignition 5.3%.

[0034] The raw materials for preparing the upper body layer include basic body powder and calcium feldspar, wherein the amount of calcium feldspar is 5-8% of the amount of basic body powder.

[0035] The chemical composition of the first base glaze layer, by weight percentage, includes: SiO2 56%, Al2O3 28%, Fe2O3 0.3%, TiO2 0.1%, CaO 0.5%, MgO 0.3%, K2O 4%, Na2O 2.5%, ZrO 26%, and loss on ignition 2.3%.

[0036] The chemical composition of the second base glaze layer, by weight percentage, includes: SiO2 62%, Al2O3 22%, Fe2O3 0.3%, TiO2 0.1%, CaO 0.5%, MgO 0.3%, K2O 2.3%, Na2O 2.5%, ZrO2 4%, ZnO 4%, and loss on ignition 2%.

[0037] The preparation method of the above-mentioned soft-light physically colored ceramic tiles includes the following steps: (1) The powders for preparing the lower and upper blanks are sequentially laid in the mold and pressed to form the lower and upper blanks, wherein the thicknesses of the lower and upper blanks are 10.5 mm and 0.8 mm, respectively.

[0038] (2) The surface of the upper blank layer is sandblasted with 80-mesh diamond abrasive at a sandblasting pressure of 0.4 MPa and a nozzle distance of 15 cm from the surface of the upper blank layer, so that the surface of the upper blank layer forms a 5-8 μm deep uneven structure, and the surface-treated upper blank layer is obtained. (3) Apply the first base glaze sequentially to the surface of the surface-treated upper body layer (the glaze slurry has a fineness of 0.4wt% residue on a 325-mesh sieve and a specific gravity of 1.42g / cm³). 3 Glazing amount is 320g / cm 2 The second base glaze (glaze slurry fineness is 0.4wt% residue on a 325-mesh sieve, specific gravity is 1.42g / cm³) 3 Glazing amount is 570g / cm 2 ) and soft-light physical coloring glaze (glaze slurry fineness is 0.4wt% residue on 325 mesh sieve, specific gravity is 1.75g / cm³) 3 Apply the glaze in three thin coats, each coat containing 280g / cm². 2 The process involves sequentially forming a first base glaze layer, a second base glaze layer, and a colored glaze layer. After drying, the material is fired in a kiln to produce the soft-light physically colored ceramic tile of this embodiment.

[0039] The firing temperature regime is as follows: first, the temperature is increased to 1140℃ at a rate of 4℃ / min and held for 20min; then the temperature is decreased to 1130℃ and held for 10min; then the temperature is increased to 1140℃ and held for 10min; the temperature-decreasing and heating cycles are repeated twice; finally, water vapor with a volume fraction of 6% is introduced, and the temperature is decreased to 700℃ at a rate of 20℃ / min, then decreased to 550℃ at a rate of 10℃ / min, and finally the kiln is discharged and cooled naturally.

[0040] Example 2 A soft-light physical coloring glaze comprises, by weight, the following raw material components: 47.6 parts of calcium-zinc based low-temperature frit, 35.7 parts of silica-coated zinc oxide, 8.3 parts of titanium dioxide, 4.8 parts of zircon sand, 0.9 parts of sodium phosphate, and 0.9 parts of calcium fluoride; the chemical composition of the calcium-zinc based low-temperature frit, by weight percentage, comprises: 60.0% SiO2, 38.7% Al2O, 12.5% ​​CaO, 2.1% MgO, 6.3% K2O, 1.6% Na2O, 1.6% BaO, and 7.2% ZnO.

[0041] A soft-light physically colored ceramic tile comprises, from bottom to top, a lower body layer, an upper body layer, a first base glaze layer, a second base glaze layer, and a colored glaze layer, wherein the colored glaze layer is fired from the aforementioned soft-light physically colored glaze.

[0042] The raw material for preparing the lower blank layer is the basic blank powder. The chemical composition of the basic blank powder, by weight percentage, includes: SiO2 68%, Al2O3 20%, Fe2O3 1.2%, TiO2 0.3%, CaO 1.2%, MgO 0.8%, K2O 2%, Na2O 1.5%, and loss on ignition 5%.

[0043] The raw materials for preparing the upper body layer include basic body powder and calcium feldspar, wherein the amount of calcium feldspar is 6% of the amount of basic body powder.

[0044] The chemical composition of the first base glaze layer, by weight percentage, includes: SiO2 55.3%, Al2O3 27.6%, Fe2O3 0.3%, TiO2 0.2%, CaO 0.5%, MgO 0.3%, K2O 4%, Na2O 3%, ZrO 25.9%, and loss on ignition 2.9%.

[0045] The chemical composition of the second base glaze layer, by weight percentage, includes: SiO2 60.0%, Al2O3 20.1%, Fe2O3 0.3%, TiO2 0.2%, CaO 0.5%, MgO 0.3%, K2O 3.8%, Na2O 2.9%, ZrO2 5.7%, ZnO 3.8%, and loss on ignition 2.4%.

[0046] The preparation method of the above-mentioned soft-light physically colored ceramic tiles includes the following steps: (1) The powders for preparing the lower and upper blanks are sequentially laid in the mold and pressed to form the lower and upper blanks, wherein the thicknesses of the lower and upper blanks are 10.5 mm and 0.8 mm, respectively.

[0047] (2) The surface of the upper blank layer is sandblasted with 80-mesh diamond abrasive at a sandblasting pressure of 0.4 MPa and a nozzle distance of 15 cm from the surface of the upper blank layer, so that the surface of the upper blank layer forms a 5-8 μm deep uneven structure, and the surface-treated upper blank layer is obtained. (3) Apply the first base glaze sequentially to the surface of the surface-treated upper body layer (the glaze slurry has a fineness of 0.4wt% residue on a 325-mesh sieve and a specific gravity of 1.42g / cm³). 3 Glazing amount is 320g / cm 2 The second base glaze (glaze slurry fineness is 0.4wt% residue on a 325-mesh sieve, specific gravity is 1.42g / cm³) 3 Glazing amount is 570g / cm 2 ) and soft-light physical coloring glaze (glaze slurry fineness is 0.4wt% residue on 325 mesh sieve, specific gravity is 1.75g / cm³) 3 Apply the glaze in three thin coats, each coat containing 280g / cm². 2 The process involves sequentially forming a first base glaze layer, a second base glaze layer, and a colored glaze layer. After drying, the material is fired in a kiln to produce the soft-light physically colored ceramic tile of this embodiment.

[0048] The firing temperature regime is as follows: first, the temperature is increased to 1140℃ at a rate of 4℃ / min and held for 25 minutes; then the temperature is decreased by 8℃ and held for 8 minutes; then the temperature is increased by 8℃ and held for 8 minutes; the temperature-increasing and decreasing cycle is repeated more than 2 times; finally, water vapor with a volume fraction of 7% is introduced, and the temperature is first decreased to 750℃ at a rate of 18℃ / min, then decreased to 550℃ at a rate of 8℃ / min, and finally the kiln is discharged and cooled naturally.

[0049] Example 3 A soft-light physical coloring glaze comprises, by weight, the following raw material components: 49.7 parts of calcium-zinc low-temperature frit, 33.0 parts of silica-coated zinc oxide, 8.5 parts of titanium dioxide, 5.0 parts of zircon sand, 0.9 parts of sodium phosphate, and 1.0 part of calcium fluoride; the chemical composition of the calcium-zinc low-temperature frit, by weight percentage, comprises: 58.9% SiO2, 37.4% Al2O, 13.6% CaO, 1.5% MgO, 7.4% K2O, 1.2% Na2O, 1.3% BaO, and 8.3% ZnO.

[0050] A soft-light physically colored ceramic tile comprises, from bottom to top, a lower body layer, an upper body layer, a first base glaze layer, a second base glaze layer, and a colored glaze layer, wherein the colored glaze layer is fired from the aforementioned soft-light physically colored glaze.

[0051] The raw material for preparing the lower blank layer is a basic blank powder. The chemical composition of the basic blank powder, by weight percentage, includes: SiO2 69.6%, Al2O3 20.0%, Fe2O3 1.0%, TiO2 0.2%, CaO 0.8%, MgO 0.6%, K2O 1.6%, Na2O 1.3%, and loss on ignition 4.9%.

[0052] The raw materials for preparing the upper body layer include basic body powder and calcium feldspar, wherein the amount of calcium feldspar is 5-8% of the amount of basic body powder.

[0053] The chemical composition of the first base glaze layer, by weight percentage, includes: SiO2 56.8%, Al2O3 28.4%, Fe2O3 0.4%, TiO2 0.1%, CaO 0.4%, MgO 0.2%, K2O 3.2%, Na2O 2.6%, ZrO 25.3%, and loss on ignition 2.6%.

[0054] The chemical composition of the second base glaze layer, by weight percentage, includes: SiO2 60.8%, Al2O3 22.0%, Fe2O3 0.4%, TiO2 0.1%, CaO 0.4%, MgO 0.2%, K2O 2.9%, Na2O 2.4%, ZrO2 4.8%, ZnO 3.4%, and loss on ignition 2.6%.

[0055] The preparation method of the above-mentioned soft-light physically colored ceramic tiles includes the following steps: (1) The powders for preparing the lower and upper blanks are sequentially laid in the mold and pressed to form the lower and upper blanks, wherein the thicknesses of the lower and upper blanks are 10.5 mm and 0.8 mm, respectively.

[0056] (2) The surface of the upper blank layer is sandblasted with 80-mesh diamond abrasive at a sandblasting pressure of 0.4 MPa and a nozzle distance of 15 cm from the surface of the upper blank layer, so that the surface of the upper blank layer forms a 5-8 μm deep uneven structure, and the surface-treated upper blank layer is obtained. (3) Apply the first base glaze sequentially to the surface of the surface-treated upper body layer (the glaze slurry has a fineness of 0.4wt% residue on a 325-mesh sieve and a specific gravity of 1.42g / cm³). 3 Glazing amount is 320g / cm 2 The second base glaze (glaze slurry fineness is 0.4wt% residue on a 325-mesh sieve, specific gravity is 1.42g / cm³) 3 Glazing amount is 570g / cm2 ) and soft-light physical coloring glaze (glaze slurry fineness is 0.4wt% residue on 325 mesh sieve, specific gravity is 1.75g / cm³) 3 Apply the glaze in three thin coats, each coat containing 280g / cm². 2 The process involves sequentially forming a first base glaze layer, a second base glaze layer, and a colored glaze layer. After drying, the material is fired in a kiln to produce the soft-light physically colored ceramic tile of this embodiment.

[0057] The firing temperature regime is as follows: first, the temperature is increased to 1130℃ at a rate of ℃ / min and held for 22 min; then the temperature is decreased by 6℃ and held for 6 min; then the temperature is increased by 6℃ and held for 6 min; the temperature-increasing and decreasing cycle is repeated more than 2 times; finally, water vapor with a volume fraction of 6% is introduced, and the temperature is first decreased to 720℃ at a rate of 16℃ / min, then decreased to 520℃ at a rate of 6℃ / min, and finally the kiln is discharged and cooled naturally.

[0058] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the raw material components of the soft light physical coloring glaze in Comparative Example 1 use an equal amount of zinc oxide to replace silicon dioxide to coat zinc oxide.

[0059] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the raw material components of the soft-light physical coloring glaze in Comparative Example 2 did not contain the phase separation agents sodium phosphate and calcium fluoride.

[0060] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that no calcium feldspar was added to the raw materials for preparing the upper body layer of the soft-light physically colored ceramic tile in Comparative Example 3, while the raw materials for preparing the lower body layer were the same.

[0061] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that the chemical composition of the second base glaze layer of the soft-light physically colored ceramic tile in Comparative Example 4 is the same as that of the first base glaze layer.

[0062] Comparative Example 5 The only difference between Comparative Example 5 and Example 1 is that, in the preparation process of the soft-light physically colored ceramic tile in Comparative Example 5, the soft-light physically colored glaze is applied in a single thick coating, i.e., the amount of glaze applied in one coat is 840 g / cm³. 2 .

[0063] Comparative Example 6 The only difference between Comparative Example 6 and Example 1 is that, in the preparation process of the soft-light physical coloring ceramic tile of Comparative Example 6, the firing temperature regime is as follows: first, the temperature is raised to 1140°C at a heating rate of 4°C / min, held for 30 minutes, and then the tile is removed from the kiln and allowed to cool naturally.

[0064] Performance testing The ceramic tile samples prepared in Examples 1-3 and Comparative Examples 1-6 were tested for coloring, mechanical properties, and acid resistance. For coloring, the glaze color values ​​(L*, a*, b*) were measured using a colorimeter (model CR-400) under D65 light source and a 10° viewing angle. For mechanical properties, Mohs hardness was tested according to GB / T 3810.4-2016; abrasion resistance was tested according to GB / T 3810.7-2016. For acid resistance, the samples were immersed in a 3% hydrochloric acid solution for 24 hours according to GB / T 3810.14-2016, and surface corrosion was observed to assess the acid resistance level. The results are shown in Table 1.

[0065] Table 1:

[0066] As shown in Table 1, the chromaticity values ​​of the ceramic tile samples prepared in Examples 1-3 are pale pink due to the difference in droplet size of the soft-light physical coloring glaze (droplet size approximately 50-100 nm, see Table 1). Figure 1 The glaze has a milky or pale blue opalescent sheen; its gloss level is 36-39°, meeting the requirements for soft-light tiles. Simultaneously, due to the promoting effect of phase-separated droplets on crystallization, a large number of crystal particles precipitate in the glaze layer (see...). Figure 2 It achieves a Mohs hardness of 6.7-6.9, a wear resistance rating of 4, and an acid resistance rating of GLA, exhibiting excellent mechanical properties and durability.

[0067] Compared to Example 1, Comparative Example 1, due to the use of ordinary zinc oxide instead of silica to coat zinc oxide, resulted in uneven phase separation of droplets and Zn... 2+ Rapid diffusion leads to the disappearance of the opalescent effect, crystallization and agglomeration of zinc silicate, and a decrease in both Mohs hardness and wear resistance.

[0068] Compared to Example 1, Comparative Example 2 has a lower content of calcium feldspar in the upper body layer, resulting in no effective transition layer and cracking of the glaze layer; in addition, impurities in the body migrate to the glaze layer, causing the glaze surface to turn yellow and crack.

[0069] Compared to Example 1, Comparative Example 3, due to the absence of sandblasting on the body, resulted in a decrease in the contact area between the body and the glaze, an increase in interfacial stress, and partial detachment of the glaze layer, as well as a decrease in hardness and wear resistance.

[0070] Compared to Example 1, Comparative Example 4 showed a decrease in acid resistance due to a decrease in the ZrO2 content in the first base glaze; and the migration of impurities in the body glaze layer caused the glaze surface to turn yellow and crack.

[0071] Compared to Example 1, Comparative Example 5, due to the single thick application of the soft-light physical coloring glaze, resulted in an increased bubble rate in the glaze layer, leading to pinholes on the glaze surface and a significant color difference. Therefore, no coloring test was performed.

[0072] Compared to Example 1, Comparative Example 6, due to the absence of a segmented firing process, resulted in insufficient phase separation in the glaze layer, preventing the formation of isolated droplets and instead producing a worm-like appearance (see [link]). Figure 3 Therefore, opalescence cannot be observed.

[0073] For those skilled in the art, several simple deductions or substitutions can be made without departing from the inventive concept, without requiring creative effort. Therefore, any simple improvements made to this invention by those skilled in the art based on the disclosure of this invention should be within the scope of protection of this invention. The above embodiments are preferred embodiments of this invention, and all processes similar to this invention and equivalent changes should fall within the scope of protection of this invention.

Claims

1. A soft-light physical coloring glaze, characterized in that, The raw material components, by weight, include: 30-50 parts of calcium-zinc low-temperature frit, 25-35 parts of silica-coated zinc oxide, 5-10 parts of titanium dioxide, 2-6 parts of zircon sand, and 1-2 parts of phase-separating agent; the chemical composition of the calcium-zinc low-temperature frit, by weight percentage, includes: 55-60% SiO2, 5-10% Al2O3, 10-15% CaO, 1-3% MgO, 5-8% K2O, 1-2% Na2O, 1-2% BaO, and 5-10% ZnO.

2. The soft-light physical coloring glaze according to claim 1, characterized in that, The particle size of the silicon dioxide-coated zinc oxide is 300-1800 nm.

3. The soft-light physical coloring glaze according to claim 1, characterized in that, The phase-separating agent is selected from at least one of calcium phosphate, calcium fluoride, and sodium phosphate.

4. A soft-light physically colored ceramic tile, characterized in that, From bottom to top, it includes a lower body layer, an upper body layer, a first base glaze layer, a second base glaze layer, and a colored glaze layer, wherein the colored glaze layer is fired from the soft-light physical coloring glaze described in any one of claims 1-3.

5. The soft-light physically colored ceramic tile according to claim 4, characterized in that, The raw material for preparing the lower blank layer is a basic blank powder. The chemical composition of the basic blank powder, by weight percentage, includes: SiO2 65-70%, Al2O3 18-22%, Fe2O3 0.8-1.5%, TiO2 0.1-0.5%, CaO 0.5-2%, MgO 0.3-1.2%, K2O 1-3%, Na2O 0.8-2.5%, and loss on ignition 4-5.5%.

6. The soft-light physically colored ceramic tile according to claim 5, characterized in that, The raw materials for preparing the upper green body layer include the basic green body powder and calcium feldspar, and the amount of calcium feldspar is 5-8% of the basic green body powder.

7. The soft-light physically colored ceramic tile according to claim 4, characterized in that, The chemical composition of the first base glaze layer, by weight percentage, includes: SiO2 53-59%, Al2O3 26-30%, Fe2O3 0.2-0.5%, TiO2 0.1-0.2%, CaO 0.3-0.8%, MgO 0.1-0.5%, K2O 2-6%, Na2O 2-4%, ZrO2 4-8%, and loss on ignition 2-5%.

8. The soft-light physically colored ceramic tile according to claim 7, characterized in that, The chemical composition of the second base glaze layer, by weight percentage, includes: SiO2 60-65%, Al2O3 20-25%, Fe2O3 0.2-0.5%, TiO2 0.1-0.2%, CaO 0.3-0.8%, MgO 0.1-0.5%, K2O 2-6%, Na2O 2-4%, ZrO2 4-8%, ZnO 3-5%, and loss on ignition 2-5%.

9. A method for preparing a soft-light physically colored ceramic tile as described in any one of claims 4-8, characterized in that, Includes the following steps: (1) The powders for preparing the lower and upper blanks are sequentially laid in the mold and pressed to form the lower and upper blanks. (2) The surface of the upper blank layer is sandblasted to form a micron-level uneven structure, thus obtaining a surface-treated upper blank layer; (3) Apply a first base glaze, a second base glaze and a soft light physical coloring glaze to the surface of the surface-treated upper body layer in sequence to form a first base glaze layer, a second base glaze layer and a color glaze layer in sequence. After drying, fire it in a kiln to obtain the soft light physical coloring ceramic brick.

10. The method for preparing ceramic bricks according to claim 9, characterized in that, The firing temperature regime is as follows: first, raise the temperature to 1120-1150℃ at a rate of 3-5℃ / min and hold for 20-30min; then lower the temperature by 5-10℃ and hold for 5-10min; then raise the temperature by 5-10℃ and hold for 5-10min; repeat the cooling and heating cycle more than twice; finally, introduce water vapor with a volume fraction of 5-8% and lower the temperature to 700-800℃ at a rate of 15-20℃ / min, then lower it to 500-600℃ at a rate of 5-10℃ / min, and finally allow it to cool naturally after exiting the kiln.

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