Tianmu green glaze and preparation method thereof

Abstract

The present invention provides a Tianmu celadon glaze and a preparation method thereof, relating to the technical field of Tianmu glaze preparation. The Tianmu celadon glaze slurry comprises inorganic raw materials and additives. The inorganic raw materials, by weight, include 10 parts frit, 10-18 parts SiO2, 7-14 parts P2O5, 5-9 parts Li2O, 8-13 parts Al2O3, 3-5 parts TiO2, 2-4 parts hematite, and 1-3 parts magnetite. The additives, by weight, include 10 parts polyacrylamide, 10-15 parts sodium tripolyphosphate, 5-9 parts sodium carboxymethylcellulose, and 2-5 parts phenylmethyldiethoxysilane. The method for preparing the Tianmu celadon glaze comprises the following steps: S1. preparing the glaze slurry, S2. spraying the glaze, and S3. firing in a reducing atmosphere. The Tianmu celadon glaze prepared by the present invention exhibits a cyan-blue or cyan-green appearance, with a beautiful and elegant appearance.

Description

Technical Field

[0001] The invention belongs to the technical field of Tianmu glaze preparation, and particularly relates to a Tianmu celadon glaze and a preparation method thereof. Background Art

[0002] Traditional Tianmu glaze refers to a special type of black porcelain glaze, known for its naturally occurring specks of various sizes that appear within the glaze. This glaze not only imparts a unique style and color to the porcelain, but its diverse color and texture also make it an ideal choice for decorative purposes on a variety of crafts and everyday items, including architecture, sculpture, ornaments, and tea bowls.

[0003] Today, there are numerous varieties of Tianmu glaze, each with its own distinctive glaze color and pattern, earning it its own unique name. For example, Oil-Drop Tianmu is renowned for its shimmering silver or bean paste-colored dots and spots scattered across a black or dark brown glaze. Wood-Leaf Tianmu uses a special process to burn leaf patterns into the glaze, reminiscent of the natural texture of leaves. Tortoise-Shell Tianmu boasts a unique glaze with a texture and color resembling a tortoise shell. Yellow Tianmu draws attention with its yellow glaze effect. Partridge-Spot Tianmu features a distinctive speckled texture resembling partridge feathers. Star-Shaped Tianmu is decorated with star-like spots or patterns, creating a sense of mystery. Black Ding Zhan is renowned for its distinctive black glaze.

[0004] Although various colors and patterns of Tianmu glazes are available in the prior art, the cyan-blue Tianmu glaze is rare. The cyan-blue Tianmu glaze is not only unique in color, but also has a more majestic and smooth appearance, adding a new color and style to the art of porcelain. Summary of the Invention

[0005] The Tianmu glaze in the prior art does not have a green glaze surface, so the present invention provides a Tianmu green glaze and a preparation method thereof. The Tianmu green glaze of the present invention has unique color and an elegant appearance.

[0006] The present invention solves the above technical problems through the following technical solutions.

[0007] The present invention provides a Tianmu celadon glaze, wherein the glaze slurry comprises inorganic raw materials and additives;

[0008] The inorganic raw materials include, by mass, 10 parts of frit, 10 to 18 parts of SiO2, 7 to 14 parts of P2O5, 5 to 9 parts of Li2O, 8 to 13 parts of Al2O3, 3 to 5 parts of TiO2, 2 to 4 parts of hematite, and 1 to 3 parts of magnetite;

[0009] The frit composition includes 40-50wt% SiO2, 10-12wt% B2O3, 9-12wt% CaO, 8-10wt% Al2O3, 2-3wt% MgO, 5.8-7wt% ZnO, 6-8wt% K2O, and 5-7wt% Na2O;

[0010] Calculated by mass, the auxiliary agent includes 10 parts of polyacrylamide (CAS No.: 9003-05-8), 10 to 15 parts of sodium tripolyphosphate (CAS No.: 7758-29-4), 5 to 9 parts of sodium carboxymethyl cellulose (CAS No.: 9004-32-4) and 2 to 5 parts of phenyl alkoxy silane.

[0011] In the present invention, the inorganic raw materials include, by mass, 10 parts of frit, 10 to 14 parts of SiO2, 9 to 12 parts of P2O5, 2.8 to 4.3 parts of Li2O, 8.4 to 9.5 parts of Al2O3, 3.7 to 4.4 parts of TiO2, 3.2 to 4.3 parts of hematite and 2.5 to 3.5 parts of magnetite.

[0012] In the present invention, the addition of Li2O can reduce the thermal expansion coefficient, adjust the thermal expansion coefficient of Tianmu celadon glaze, and avoid glaze defects caused by excessive thermal expansion coefficient.

[0013] In the present invention, the additives include, by weight, 10 parts polyacrylamide, 10-12 parts sodium tripolyphosphate, and 5-7 parts sodium carboxymethylcellulose. Among the additives, sodium tripolyphosphate helps improve the uniformity and transparency of the glaze slurry; sodium carboxymethylcellulose is a good thickener and emulsifier, capable of adjusting the viscosity of the glaze slurry; polyacrylamide forms a more stable dispersion system than common surfactants; and the phenylalkoxysilane is an organosilicon with excellent weather resistance, water resistance, and anti-adhesion properties.

[0014] In the present invention, the frit composition is 45.8wt% SiO2, 11.3wt% Al2O3, 9.1wt% CaO, 9.9wt% B2O3, 2.7wt% MgO, 6.8wt% ZnO, 7.3wt% K2O, 6.6wt% Na2O, and the rest are unavoidable impurities.

[0015] In the present invention, the phenylalkoxysilane includes at least one of phenyldiethoxysilane (17872-93-4), phenylmethyldiethoxysilane (CAS No.: 775-56-4), methyldiphenylethoxysilane (1825-59-8), and phenyltrimethoxysilane (2996-92-1); preferably, phenyldiethoxysilane or methyldiphenylethoxysilane.

[0016] In the present invention, the mass ratio of the inorganic raw material to the auxiliary agent is 10:1-3, preferably 10:2-2.7.

[0017] In the present invention, the mass ratio of hematite to magnetite is 1.2 to 1.8, preferably 1.3 to 1.6.

[0018] In the present invention, iron can form a glaze of various colors under a high-temperature reducing atmosphere. Ferric ions and ferrous ions can form complexes with phosphates and silicates. The color of these complexes depends on the valence of the ions and the chemical properties of the surrounding environment. For example, the concentration of iron ions, the ratio of Fe2+ to Fe3+, and the degree of dispersion of iron ions in the glaze all affect the color. Under the reducing atmosphere of the present invention, when iron exists in the form of Fe2+, it will appear blue; when iron exists in the form of Fe3+, it may appear green or yellow.

[0019] In the present invention, the sum of the mass of magnetite and hematite accounts for 6-9% of the total mass of the inorganic raw materials, preferably 7-8.5%. Among them, when the sum of the mass of magnetite and hematite accounts for a larger proportion of the total mass of the inorganic raw materials, the color of the glaze will be darker.

[0020] In the present invention, the mass of the P2O5 accounts for 13-21% of the total mass of the inorganic raw materials, preferably 16-19.5%.

[0021] In the present invention, P2O5 is added to the glaze slurry as a flux, which can help the inorganic raw materials to dissolve and mix better, thereby forming a more uniform microstructure; in addition, phosphorus pentoxide can promote the crystallization of titanium dioxide, which also helps to improve the whiteness of the glaze.

[0022] In the present invention, the TiO2 accounts for 4-9% of the total mass of the inorganic raw materials, preferably 5-8%. The crystals of titanium silicate precipitated by the TiO2 promote the enrichment of iron, thereby forming the stripes of the Tianmu glaze. When too much TiO2 is added, the stripes are relatively wide, while when too little is added, the stripes are small and sparse.

[0023] In the present invention, the specific gravity of the glaze slurry is 1.43-1.47 g / cm 3 , preferably 1.45~1.48g / cm 3 .

[0024] In the present invention, the flow coefficient of the glaze slurry is 1.24-1.37, preferably 1.26-1.33.

[0025] In the present invention, the Mw of the polyacrylamide is between 8 and 10 million.

[0026] In the present invention, the polyacrylamide is a cationic polyimide.

[0027] In the present invention, the viscosity of sodium carboxymethyl cellulose is 1500 to 2800 mPa·s.

[0028] The present invention also provides a method for preparing Tianmu celadon glaze, comprising the following steps:

[0029] S1. Preparation of glaze slurry:

[0030] Wet-grinding and sieving the inorganic raw materials to obtain a mixture; adding water and additives to the mixture and mixing to obtain a glaze slurry;

[0031] S2. Spray glaze:

[0032] Spraying the glaze slurry onto the surface of the blank and then drying it to obtain a semi-finished product;

[0033] S3. Firing:

[0034] a. Preheating stage: Heat the semi-finished product to 490-510℃ and preheat for 30-50 minutes. During the preheating stage, the oxygen content is controlled below 2% and the carbon monoxide content is controlled between 2% and 5%.

[0035] b. Holding stage: heat to 1200-1220℃ and hold for 100-150min. The oxygen content in the holding stage is 0.2-0.5% and the carbon monoxide content is 4-8%.

[0036] c. Cooling: Cool the glaze to 250-300℃ with the furnace, then open the kiln door and cool it to 20-30℃ with air. Cooling has a significant impact on the shape and color of the crystals. Direct water cooling or air cooling will result in a dark yellow glaze, and water cooling or air cooling will also cause uneven distribution of streaks.

[0037] In S1, during the wet grinding process, the mass ratio of ball stone: inorganic raw material: water is 1:1.5:0.7-0.8, wherein the ball stone is a corundum porcelain ball.

[0038] In S1, the wet grinding speed is 400-500 rpm.

[0039] In S1, the wet grinding time is 4 to 8 hours.

[0040] In S2, the glaze spraying thickness is controlled to be 0.25-0.3 mm. If the glaze spraying thickness is too thick, it will lead to difficulty in restoration and fail to present the blue color, while if the glaze spraying thickness is insufficient, it will affect the smoothness of the glaze surface.

[0041] In S2, the distance between the glaze spraying gun and the blank is 200-300 mm.

[0042] In S2, the whiteness of the green body is ≥80%.

[0043] In S2, the thermal expansion coefficient of the blank is 5.33~5.48×10 -6 / ℃.

[0044] In S3, the air and moisture in the kiln can be discharged by heating in the early stage of the preheating stage, and part of the iron oxide can be reduced to ferrous oxide and oxygen. The oxygen content in the kiln needs to be discharged during the preheating stage, which is beneficial to the color control in the subsequent insulation stage. On the other hand, inorganic raw materials with low melting points can also generate corresponding silicates in a reducing atmosphere, because alkaline oxides such as MgO, K2O and Na2O in inorganic raw materials exist in the form of oxides and have good compatibility with acidic oxides (such as P2O5) in the glaze, which ultimately leads to poor iron enrichment. In addition, preheating can allow phenylalkoxysilane to fully react with inorganic raw materials, forming an organic film on the glaze surface, thereby increasing the stain resistance of the glaze.

[0045] In S3, the heating rates of the preheating stage and the holding stage are independently 12-15°C / min.

[0046] In S3, the oxygen content in the preheating stage is controlled at 1.0-1.8%, and the carbon monoxide content is controlled at 2-4%.

[0047] In S3, the oxygen content in the heat preservation stage is controlled at 0.2-0.3%, and the carbon monoxide content is controlled at 6-8%. Excessively high or low oxygen and carbon monoxide contents will affect the glaze color.

[0048] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1. By adjusting the ratio of hematite to magnetite, as well as the ratio of their combined mass to the total mass of the inorganic raw materials, the present invention achieves clear, moderately dense stripes in Tianmu celadon glaze. The addition of an appropriate amount of titanium dioxide promotes iron enrichment, favoring the formation of stripes; phosphorus pentoxide acts as a dispersant, preventing large, localized accumulation of cyan blocks. Ultimately, the Tianmu celadon glaze produced by the present invention has two hues: blue-blue and green-blue, with distinct stripes and a beautiful and elegant appearance.

[0051] 2. The process of the present invention involves three steps: glaze slurry preparation, glazing and firing. Strict firing temperature, firing reducing atmosphere and cooling method are selected to make the color of Tianmu celadon glaze more unique. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Surface images of glazes prepared in the examples and comparative examples of the present invention. DETAILED DESCRIPTION

[0053] To facilitate understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0054] GB / T 23460.1-2009 Ceramic glaze performance test method Part 1: High temperature fluidity test melt flow method

[0055] The frit compositions used in the following examples are shown in Table 1:

[0056] Table 1

[0057]

[0058] The raw material information used in the present invention is shown in Table 2:

[0059] Table 2

[0060] name Manufacturer or model Property parameters polyacrylamide Wengjiang, Guangdong Cationic, Mw.12 million Sodium carboxymethyl cellulose Wengjiang, Guangdong Viscosity 1500~2800mPa·s hematite Hubei Guangao - magnetite Hebei Zhuofei - <![CDATA[TiO2]]> Anatase -

[0061] The surface whiteness of the blank of the present invention is 90%, and the thermal expansion coefficient of the bottom glaze on the surface of the blank is 5.37×10 -6 / ℃. The thermal expansion coefficient of the glaze of the present invention needs to be controlled within the range of 4.92~5.23×10 -6 / ℃, if the difference in thermal expansion coefficient between the blank and the glaze is large, it will cause cracks or even peeling of the glaze. If the difference in thermal expansion coefficient is too small, the glaze will be subjected to compressive stress during the cooling process, which will also cause defects in the glaze.

[0062] Example 1

[0063] 1. The glaze slurry formula of the Tianmu celadon glaze of this embodiment is as follows:

[0064] Inorganic raw materials: 10 parts of frit, 16.7 parts of SiO2, 10 parts of P2O5, 8.3 parts of Li2O, 8.5 parts of Al2O3, 4.4 parts of TiO2, 2.6 parts of hematite, 1.7 parts of magnetite;

[0065] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate, 7 parts sodium carboxymethyl cellulose and 3 parts phenyldiethoxysilane.

[0066] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.5.

[0067] 2. The preparation method of the Tianmu celadon glaze of this embodiment is as follows:

[0068] S1. Preparation of glaze slurry:

[0069] The inorganic raw materials were wet-milled at 400 rpm for 4 hours and passed through a 200-mesh sieve to obtain a mixture; water and additives were added to the mixture and mixed to obtain a glaze slurry. The flow coefficient of the glaze was 1.26, and the specific gravity of the glaze slurry was 1.46 g / cm 3 ;

[0070] S2. Spray glaze:

[0071] Spray the glaze slurry onto the surface of the blank, with the spray gun mouth 300mm away from the blank and the glaze spraying thickness of 0.3mm, and then dry to obtain a semi-finished product;

[0072] S3. Firing:

[0073] a. Preheating stage: Heat the semi-finished product to 200℃ at a heating rate of 15℃ / min for 40 minutes. During the preheating stage, nitrogen is introduced and the oxygen content is adjusted to 1.5% and the carbon monoxide content to 3%.

[0074] b. Holding stage: Heat to 1200°C at a heating rate of 15°C / min and hold for 130 minutes. During this holding stage, the oxygen content is 0.2% and the carbon monoxide content is 6%.

[0075] c. Cooling: Cool with the furnace to 300℃, then open the kiln door and cool with air to 20℃.

[0076] The glaze surface obtained in this embodiment is shown in the attached figure. Figure 1 Example 1.

[0077] Example 2

[0078] 1. The glaze slurry formula of the Tianmu celadon glaze of this embodiment is as follows:

[0079] Inorganic raw materials: 10 parts of frit, 14 parts of SiO2, 12.7 parts of P2O5, 7.8 parts of Li2O, 11.4 parts of Al2O3, 3.3 parts of TiO2, 3.3 parts of hematite, 2.1 parts of magnetite;

[0080] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate, 7 parts sodium carboxymethyl cellulose and 3 parts methyl diphenyl ethoxy silane.

[0081] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.2.

[0082] 2. The preparation method of Tianmu green glaze in this embodiment is the same as that in Example 1.

[0083] The flow coefficient of the glaze prepared in this embodiment is 1.28, and the specific gravity of the glaze slurry is 1.45 g / cm 3 .

[0084] The glaze surface obtained in this embodiment is shown in the attached figure. Figure 1 Example 2.

[0085] Example 3

[0086] 1. The glaze slurry formula of the Tianmu celadon glaze of this embodiment is as follows:

[0087] Inorganic raw materials: 10 parts of frit, 18 parts of SiO2, 13.6 parts of P2O5, 6.8 parts of Li2O, 11.8 parts of Al2O3, 3.7 parts of TiO2, 2.9 parts of hematite, 2.1 parts of magnetite;

[0088] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate, 7 parts sodium carboxymethyl cellulose and 4 parts phenyldiethoxysilane.

[0089] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.5.

[0090] 2. The preparation method of Tianmu green glaze in this embodiment is the same as that in Example 1.

[0091] The glaze prepared in this embodiment has a flow coefficient of 1.26 and a glaze slurry specific gravity of 1.45 g / cm 3 .

[0092] The glaze surface obtained in this embodiment is shown in the attached figure. Figure 1 Example 3.

[0093] Comparative Example 1

[0094] 1. The glaze formula of the Tianmu celadon glaze of this comparative example is as follows:

[0095] Inorganic raw materials: 10 parts of frit, 16.7 parts of SiO2, 9 parts of P2O5, 8.3 parts of Li2O, 8.5 parts of Al2O3, 4.4 parts of TiO2, 2.6 parts of hematite, 1.7 parts of magnetite;

[0096] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate, 7 parts sodium carboxymethyl cellulose and 3 parts phenyldiethoxysilane.

[0097] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.5.

[0098] 2. The preparation method of the Tianmu celadon glaze of this comparative example is the same as that of Example 1, except that the firing method in S3 is different. Specifically, the firing process is as follows:

[0099] S3. Firing:

[0100] a. Introduce nitrogen into the kiln, and proceed directly to step b after exhausting the air;

[0101] b. Holding stage: heating at a rate of 15°C / min to 1200°C and holding for 200 minutes. During the holding stage, the oxygen content is 0.2% and the carbon monoxide content is 3%;

[0102] c. Cooling: Cool with the furnace to 300℃, then open the kiln door and cool with air to 20℃.

[0103] The flow coefficient of the glaze prepared in this comparative example is 1.26, and the specific gravity of the glaze slurry is 1.45 g / cm 3 .

[0104] The glaze surface obtained in this comparative example is shown in the attached figure. Figure 1 Comparative Example 1.

[0105] Comparative Example 2

[0106] 1. The glaze formula of the Tianmu celadon glaze of this comparative example is as follows:

[0107] Inorganic raw materials: 10 parts of frit, 17 parts of SiO2, 9.8 parts of P2O5, 7 parts of Li2O, 8.3 parts of Al2O3, 4.1 parts of TiO2, 5 parts of hematite, 0.8 parts of magnetite;

[0108] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate and 7 parts sodium carboxymethyl cellulose.

[0109] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.5.

[0110] 2. The preparation method of Tianmu green glaze in this comparative example is the same as that in comparative example 2.

[0111] The flow coefficient of the glaze prepared in this comparative example is 1.26, and the specific gravity of the glaze slurry is 1.45 g / cm 3 .

[0112] The glaze surface obtained in this comparative example is shown in the attached figure. Figure 1 Comparative Example 2.

[0113] Comparative Example 3

[0114] 1. The glaze formula of the Tianmu celadon glaze of this comparative example is as follows:

[0115] Inorganic raw materials: 10 parts of frit, 16.1 parts of SiO2, 8.7 parts of P2O5, 7.3 parts of Li2O, 8.5 parts of Al2O3, 6 parts of TiO2, 2.6 parts of hematite, 1.7 parts of magnetite;

[0116] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate, 7 parts sodium carboxymethyl cellulose and 3 parts methyl diphenyl ethoxy silane.

[0117] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.5.

[0118] 2. The preparation method of Tianmu green glaze in this comparative example is the same as that in Example 1.

[0119] The flow coefficient of the glaze prepared in this comparative example is 1.26, and the specific gravity of the glaze slurry is 1.45 g / cm 3 .

[0120] The glaze surface obtained in this comparative example is shown in the attached figure. Figure 1 Comparative Example 3.

[0121] Comparative Example 4

[0122] 1. The glaze formula of the Tianmu celadon glaze of this comparative example is as follows:

[0123] Inorganic raw materials: 10 parts of frit, 18 parts of SiO2, 4 parts of P2O5, 7.3 parts of Li2O, 8.5 parts of Al2O3, 4.4 parts of TiO2, 2.6 parts of hematite, 1.7 parts of magnetite;

[0124] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate, 7 parts sodium carboxymethyl cellulose and 3 parts methyl diphenyl ethoxy silane.

[0125] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.5.

[0126] 2. The preparation method of Tianmu green glaze in this comparative example is the same as that in Example 1.

[0127] The flow coefficient of the glaze prepared in this comparative example is 1.26, and the specific gravity of the glaze slurry is 1.45 g / cm 3 .

[0128] The glaze surface obtained in this comparative example is shown in the attached figure. Figure 1 Comparative Example 4.

[0129] Comparative Example 5

[0130] 1. The glaze formula of the Tianmu celadon glaze of this comparative example is as follows:

[0131] Inorganic raw materials: 10 parts of frit, 18 parts of SiO2, 4 parts of P2O5, 7.3 parts of Li2O, 8.5 parts of Al2O3, 4.4 parts of TiO2, 2.6 parts of hematite, 1.7 parts of magnetite;

[0132] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate, 7 parts sodium carboxymethyl cellulose and 4 parts methyl diphenyl ethoxy silane.

[0133] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.5.

[0134] 2. The preparation method of Tianmu celadon glaze in this comparative example is the same as that in Example 1.

[0135] The flow coefficient of the glaze prepared in this comparative example is 1.26, and the specific gravity of the glaze slurry is 1.45 g / cm 3 .

[0136] The glaze surface obtained in this comparative example is shown in the attached figure. Figure 1 Comparative Example 5.

[0137] Comparative Example 6

[0138] 1. The glaze formula of the Tianmu celadon glaze of this comparative example is as follows:

[0139] Inorganic raw materials: 10 parts of frit, 16.7 parts of SiO2, 10 parts of P2O5, 8.3 parts of Li2O, 8.5 parts of Al2O3, 4.4 parts of TiO2, 2.6 parts of hematite, 1.7 parts of magnetite;

[0140] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate, 7 parts sodium carboxymethyl cellulose and 4 parts methyl diphenyl ethoxy silane.

[0141] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.5.

[0142] 2. The preparation method of Tianmu celadon glaze in this embodiment is the same as that in Example 1, except that c. the cooling method in S3 is different. Specifically, the cooling step is c. cooling: cooling with furnace air at 20°C.

[0143] The glaze surface obtained in this comparative example is shown in the attached figure. Figure 1 Comparative Example 6.

[0144] Comparative Example 7

[0145] 1. The glaze formula of the Tianmu celadon glaze of this comparative example is as follows:

[0146] Inorganic raw materials: 10 parts of frit, 16.7 parts of SiO2, 10 parts of P2O5, 8.3 parts of Li2O, 8.5 parts of Al2O3, 4.4 parts of TiO2, 2.6 parts of hematite, 1.7 parts of magnetite;

[0147] Additives: 10 parts polyacrylamide, 12 parts sodium tripolyphosphate, 7 parts sodium carboxymethyl cellulose and 3 parts methyl diphenyl ethoxy silane.

[0148] The mass ratio of inorganic raw materials: auxiliary agents is 10:2.5.

[0149] 2. The preparation method of Tianmu celadon glaze in this embodiment is the same as that in Example 1, except that c. the cooling method in S3 is different. Specifically, the cooling step is c. cooling: cooling with furnace air at 20°C.

[0150] Effect embodiment

[0151] The thermal expansion coefficient test method refers to GB / T 3810.8-2016, Test methods for ceramic tiles, Part 8: Determination of linear thermal expansion. The sewage resistance test method refers to GB / T 3810.14-2016, Test methods for ceramic tiles, Part 14: Determination of resistance to staining.

[0152] The glaze slurries of the above examples and comparative examples and the effects of the prepared glazes are shown in Table 3:

[0153] Table 3

[0154]

[0155] The Tianmu celadon glaze obtained in Examples 1 and 2 has a blue hue. The TiO2 added in Example 1 is relatively larger than that in Example 2. In Example 1, TiO2 forms more titanium silicate crystals, which helps to enrich iron. Therefore, the stripes in Example 1 are denser than those in Example 2. In Example 3, the mass ratio of hematite to magnetite is lower, which affects the Fe 2+ and Fe 3+ ratio, resulting in a greenish hue.

[0156] Comparative Example 1 lacks a preheating stage, so oxygen and water aren't expelled promptly. Furthermore, the absence of a preheating stage encourages alkali metals to form metal silicates, hindering the phase separation of phosphorus pentoxide. Consequently, the resulting glaze has a yellowish-cyan tint and exhibits long, overlapping streaks. In Comparative Example 2, the hematite-to-magnetite ratio is 6.3:1, and the combined mass of hematite and magnetite accounts for 9.3% of the total inorganic raw material mass. The high iron content results in a brownish-yellow glaze and darker streaks. Furthermore, Comparative Example 2 lacks phenylalkoxysilane glaze modification, resulting in poor stain resistance. In Comparative Example 3, TiO₂ accounts for 9.9% of the total inorganic raw material mass, resulting in nearly overlapping streaks and a lack of distinct blue and green hues. In Comparative Example 4, P₂O₅ accounts for 7.1% of the total inorganic raw material mass. This too little P₂O₅, as a dispersed phase, results in localized concentrations of bluish-cyan color, making it difficult to form streaks. In Comparative Example 5, too little Li2O was added, resulting in a high thermal expansion coefficient for the glaze, which ultimately resulted in an uneven, rough glaze surface with glaze defects. Comparative Example 6, which was cooled with air, formed dark yellow spots, which were unevenly distributed.

[0157] Unless otherwise defined, all professional terms used in this article have the same meanings as those generally understood by those skilled in the art. The professional terms used in this article are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present invention can be purchased on the market or can be prepared by existing methods. The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A Tianmu celadon glaze, characterized in that: The glaze slurry includes inorganic raw materials and additives; The inorganic raw materials include, by mass, 10 parts of frit, 10-18 parts of SiO2, 7-14 parts of P2O5, 5-9 parts of Li2O, 8-13 parts of Al2O3, 3-5 parts of TiO2, 2-4 parts of hematite, and 1-3 parts of magnetite; The frit composition includes 40-50 wt% SiO2, 10-12 wt% B2O3, 9-12 wt% CaO, 8-10 wt% Al2O3, 2-3 wt% MgO, 5.8-7 wt% ZnO, 6-8 wt% K2O, and 5-7 wt% Na2O; Calculated by weight, the auxiliary agent includes 10 parts of polyacrylamide, 10-15 parts of sodium tripolyphosphate, 5-9 parts of sodium carboxymethyl cellulose and 2-5 parts of phenylmethyldiethoxysilane.

2. The Tianmu celadon glaze according to claim 1, characterized in that: The glaze slurry satisfies at least one of the following conditions (1) to (4): (1) The inorganic raw materials include, by mass, 10 parts of frit, 10-14 parts of SiO2, 9-12 parts of P2O5, 2.8-4.3 parts of Li2O, 8.4-9.5 parts of Al2O3, 3.7-4.4 parts of TiO2, 3.2-4.3 parts of hematite and 2.5-3.5 parts of magnetite; (2) The auxiliary agent comprises, by weight, 10 parts of polyacrylamide, 10 to 12 parts of sodium tripolyphosphate, and 5 to 7 parts of sodium carboxymethyl cellulose; (3) The frit composition is 45.8wt% SiO2, 11.3wt% Al2O3, 9.1wt% CaO, 9.9wt% B2O3, 2.7wt% MgO, 6.8wt% ZnO, 7.3wt% K2O, 6.6wt% Na2O, and the rest are unavoidable impurities; (4) The phenylalkoxysilane includes at least one of phenyldiethoxysilane, phenylmethyldiethoxysilane, methyldiphenylethoxysilane and phenyltrimethoxysilane.

3. The Tianmu celadon glaze according to claim 1, characterized in that: The mass ratio of the inorganic raw material to the auxiliary agent is 10:1-3.

4. The Tianmu celadon glaze according to claim 1, characterized in that: The mass ratio of the inorganic raw material to the auxiliary agent is 10:2-2.

7.

5. The Tianmu celadon glaze according to claim 1, characterized in that: The inorganic raw material satisfies at least one of the following conditions (1) to (4): (1) The mass ratio of hematite to magnetite is 1.2 to 1.8; (2) The sum of the mass of magnetite and hematite accounts for 6-9% of the total mass of inorganic raw materials; (3) The mass of the P2O5 accounts for 13-21% of the total mass of the inorganic raw materials; (4) The TiO2 accounts for 4-9% of the total mass of the inorganic raw materials.

6. The Tianmu celadon glaze according to claim 1, characterized in that: The inorganic raw material satisfies at least one of the following conditions (1) to (4): (1) The mass ratio of hematite to magnetite is 1.3 to 1.6; (2) The sum of the mass of magnetite and hematite accounts for 7-8.5% of the total mass of inorganic raw materials; (3) The mass of the P2O5 accounts for 16-19.5% of the total mass of the inorganic raw materials; (4) The TiO2 accounts for 5-8% of the total mass of the inorganic raw materials.

7. The Tianmu celadon glaze according to claim 1, characterized in that: The glaze slurry satisfies at least one of the following conditions (1) to (2): (1) The specific gravity of the glaze slurry is 1.43~1.47g / cm 3 ; (2) The flow coefficient of the glaze slurry is 1.24~1.

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8. The Tianmu celadon glaze according to claim 1, characterized in that: The glaze slurry satisfies at least one of the following conditions (1) to (2): (1) The specific gravity of the glaze slurry is 1.45~1.48g / cm 3 ; (2) The flow coefficient of the glaze slurry is 1.26~1.

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9. The Tianmu celadon glaze according to claim 1, characterized in that: The auxiliary agent satisfies at least one of the following conditions (1) to (3): (1) The Mw of the polyacrylamide is between 8 and 12 million; (2) The polyacrylamide is a cationic polyimide; (3) The viscosity of sodium carboxymethyl cellulose is 1500~2800mPa·s.

10. The method for preparing Tianmu celadon glaze according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Preparation of glaze slurry: Wet-grinding and sieving the inorganic raw materials to obtain a mixture; adding water and additives to the mixture and mixing to obtain a glaze slurry; S2. Spray glaze: Spraying the glaze slurry onto the surface of the blank and then drying it to obtain a semi-finished product; S3. Firing: a. Preheating stage: Heat the semi-finished product to 490-510℃ and preheat for 30-50 minutes. During the preheating stage, the oxygen content is controlled below 2% and the carbon monoxide content is controlled at 2-5%. b. Holding stage: Heat to 1200-1220℃ and hold for 100-150 minutes. During the holding stage, the oxygen content is 0.2-0.5% and the carbon monoxide content is 4-8%. c. Cooling: Cool with the furnace to 250~300℃, then open the kiln door and cool with air to 20~30℃.

11. The method for preparing Tianmu celadon glaze according to claim 10, characterized in that: The process for preparing the glaze slurry satisfies at least one of the following conditions (1) to (4): (1) During the wet grinding process, the mass ratio of ball stone: inorganic raw material: water is 1:1.5:0.7-0.8; (2) The wet grinding speed is 400-500 rpm; (3) The wet grinding time is 4 to 8 hours; (4) The mesh size of the sieving is 200-250 mesh.

12. The method for preparing Tianmu celadon glaze according to claim 10, characterized in that: The glaze spraying process satisfies at least one of the following conditions (1) to (4): (1) The glaze thickness is controlled at 0.25~0.3mm; (2) The distance between the glaze spray gun and the blank is 200~300mm; (3) The whiteness of the green body is ≥80%; (4) The thermal expansion coefficient of the blank is between 5.33 and 5.48 × 10 -6 / ℃.

13. The method for preparing Tianmu celadon glaze according to claim 10, characterized in that: The firing process satisfies at least one of the following conditions (1) to (3): (1) The heating rates in the preheating stage and the holding stage are independently 12~15℃ / min; (2) During the preheating stage, the oxygen content is controlled at 1.0~1.8% and the carbon monoxide content is controlled at 2~4%; (3) During the insulation stage, the oxygen content is controlled at 0.2~0.3% and the carbon monoxide content is controlled at 6~8%.

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