Preparation method of underglaze decorative ceramic product

Abstract

The invention discloses a preparation method of an underglaze decorative ceramic product, which comprises the following steps: (1) preparing a blank: preparing the blank from pottery clay, feldspar, quartz and elutriation mud as raw materials; (2) preparation of white ground glaze: taking quartz, limestone, feldspar, black mud, talc, barium carbonate, zinc oxide, zircon powder and frit as ground glaze raw materials, performing ball milling, deironing, sieving and blending into glaze slip; (3) preparation of green transparent cover glaze: taking kaolin, quartz, feldspar, dolomite, calcite, cupric carbonate, barium chromate and frit as raw materials, carrying out ball milling, iron removal and sieving, and blending into glaze slip; (4) molding and fettling a blank; (5) applying ground glaze to the blank; (6) sintering the blank; (7) applying cover glaze to the product; and (8) firing the product. The invention has the following advantages: the argil is used as a main raw material to prepare the blank, so that the effects of low cost and full utilization of resources are achieved; double-layer glaze treatment is adopted, the problems that a ceramic product contains many impurities and a blank is difficult to decorate are solved at low cost, the ceramic product decorated under the glaze is manufactured, the glaze surface of the product is bright and elegant, a transmutation irregular pattern is shown under a transparent glaze layer, and the ceramic product is random, interesting, color-like, non-color-like, transmutation-like and higher in aesthetic feeling; and daily use and fine ceramic development of art are facilitated.

Description

[0001] The invention relates to the technical field of ceramic production, and in particular to a method for preparing an underglaze decorated ceramic product. Background Art

[0002] There are two types of ceramic products for daily use, namely porcelain products and pottery products. Porcelain products have low water absorption and high strength. Usually, the body parts are of high whiteness. Kaolin is the main raw material, and some are added with aggregate to become bone porcelain. The white body parts of porcelain products are conducive to the appearance decoration of products, including overglaze, underglaze, and medium glaze painting, which can have good effects. The overall value and price are better than pottery products. Pottery products have high water absorption and low strength. Usually, the body parts are not high. The body parts of most products are red, gray, etc. Pottery products use clay as the main raw material. In addition to precious mineral materials such as purple sand, general clay contains more impurities. A large amount of impurities decompose and volatilize during firing, affecting the appearance of the product, and it is not ideal in terms of painted decoration. No wonder the ceramic flower pots that cost a few dollars on the market are jokingly called selling mud. In the industry, engineers and technicians have been working hard to develop ceramic products into fine ceramics, but have not yet broken through the difficulties of high costs and limited benefits. In particular, the decoration of daily fine ceramics tends to be underglaze, which is extremely unsatisfactory on ceramic products. If multi-level decoration is adopted, the defects caused by the decomposition and volatilization of impurities in ceramic products can be transformed into defective beauty. Although this innovation cannot completely make the appearance decoration of the product reach the effect of high-quality porcelain, it can make the product achieve elegant decoration and unique interest, and make clay produce high-quality fine ceramics. It also promotes mass production to meet market demand, which sets up new research topics for the ceramic industry in terms of technology and process innovation. Summary of the invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide a method for preparing underglaze decorative ceramic products with clay as the main raw material, which has a bright glaze surface and can see through the surface of the white base glaze under the glaze to present light patterns. These light patterns under the glaze are random, look like color but not color, and look like kiln changes. They are interesting and have decorative effects, making the ceramic products tend to be refined ceramics, which is beneficial to the effective utilization of clay.

[0004] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing an underglaze decorative ceramic product, characterized in that it includes the following process steps: (1) Billet preparation ①Formula of blank: Take the following materials by weight percentage: Pottery clay 52-58%, feldspar 16-20%, quartz 8-12%, panning mud 15-19%; ②Blank preparation The process is carried out according to a conventional method for preparing blanks for producing ceramic products, and the blanks for producing ceramic products are prepared for use; (2) Preparation of white base glaze ①White base glaze formula: Take the following materials by weight percentage: Quartz 11-15%, limestone 8-10%, feldspar 17-20%, black mud 8-12%, talc 6-8%, barium carbonate 4-6%, zinc oxide 6-8%, zircon powder 8-12%, frit 18-22%; The frit is composed of the following materials: by weight: quartz 26-30%, feldspar 22-24%, borax 15-18%, zinc oxide 7-9%, zircon 10-12%, calcium carbonate 9-12%, potassium nitrate 3-5%; Preparation of the frit: mixing the materials in the formula, smelting them and quenching them with water to obtain a crystalline block; ② Preparation of white base glaze The above raw materials are mixed and then added with clean water for ball milling. After ball milling, the raw materials are passed through an iron remover for iron removal. The iron-removed raw materials are sieved with 200 meshes. The sieved raw materials are mixed with clean water and prepared into a glaze slurry with a concentration of 38 degrees Baume for standby use. (3) Preparation of green transparent glaze ①Green transparent glaze formula: Take the following materials by weight percentage: Kaolin 9-12%, quartz 16-19%, feldspar 10-12%, dolomite 3-5%, calcite 4.5-6.5%, copper carbonate 0.8-1.2%, barium chromate 0.4-0.6%, frit 48-52%; The frit is composed of the following materials: by weight percentage: 10-12% kaolin, 14-16% limestone, 16-18% feldspar, 20-24% borax, 22-26% quartz, and 10-12% soda ash; Preparation of the frit: mixing the materials in the formula, smelting them and quenching them with water to obtain a crystalline block; ② Preparation of green transparent glaze The above raw materials are mixed and then added with clean water for ball milling. After ball milling, the raw materials are passed through an iron remover for iron removal. The iron-removed raw materials are sieved with 200 meshes. The sieved raw materials are mixed with clean water and prepared into a glaze slurry with a concentration of 32 degrees Baume for standby use. (4) Molding and trimming of ceramic parts The above-mentioned blank is molded according to a conventional molding method for ceramic tires to prepare a ceramic tire; the ceramic tire is naturally dried for 8-12 hours, and the surface of the ceramic tire is trimmed by using bamboo pieces, brushes, soft cloth and clean water to remove the mold lines and make the surface flat and smooth; the trimmed ceramic tire is naturally dried for 24-36 hours; (5) Applying base glaze to ceramic parts The above-mentioned white base glaze is used for glazing; before glazing, the ceramic body is placed on a small platform rotating slowly, and a small spray gun is used to add clean water to spray water intermittently on the surface of the rotating ceramic body, and the area of ​​the ceramic body surface sprayed with water accounts for 20-30% of the total area of ​​the ceramic body surface; the ceramic body sprayed with water immediately enters the glaze liquid pool for glazing, and the glazing time is 2-3 seconds; the glazed ceramic body is naturally dried for 8-12 hours; (6) Sintering of ceramic parts The ceramic body with white base glaze is sintered in a kiln for ceramic production at a temperature of 800-820°C for 6-8 hours in an oxidizing atmosphere. The products out of the kiln are white ceramic products. (7) Applying glaze to ceramic products The green transparent glaze is used to glaze the sintered ceramic products by manual dipping, the dipping time is 3-4 seconds, and the glazed ceramic products are naturally dried for 8-12 hours; (8) Firing of ceramic products The ceramic products with the glaze applied are fired in a kiln for ceramic production; the firing time is 10-12 hours, the firing temperature is 1160-1180° C., and the firing atmosphere is an oxidizing atmosphere.

[0005] The main principle of the present invention is: double-layer glazing is adopted. Before glazing the white base glaze, water is sprayed intermittently on the body part, so that the humidity deviation of the clay body part surface is generated, causing the deviation of the glaze absorption thickness during the glazing process. In the subsequent firing, the glaze layer is vitrified to enhance the light transmittance of the glaze layer, and the uneven glaze layer of the original white base glaze is revealed. The body part's true color can be vaguely seen in the thin glaze, showing a hazy pattern similar to water splashes; during the sintering of the body part, the impurities contained in the body part are decomposed and volatilized, leaving a large number of small pores on the surface of the white base glaze. When the amount of volatiles is large, they react with the white base glaze, leaving a pattern similar to smoke or marble cross-section layer. In the subsequent firing, the volatiles of the body part have been reduced, and the double-layer glaze layer promotes the small pores on the white base glaze to be converted into small glaze bubbles. The color water splashes, glaze bubbles, smoke, etc. that appear on the white base glaze through kiln change constitute a natural and unique decorative pattern, and the light transmittance of the transparent top glaze forms an interesting underglaze decoration; the fired product becomes a ceramic fine pottery, which is also a disguised underglaze decorative ceramic product.

[0006] The product prepared by the present invention has the following advantages: 1. The present invention uses common clay containing more impurities as the main raw material to prepare blanks suitable for the production of ceramic products, achieving the effect of low cost and full utilization of resources; 2. The present invention is aimed at double-layer glaze treatment of red pottery. The color of the red pottery body is dark red or dark gray, and the original color is not white enough, which is not conducive to painting and decoration. The original color of the body is changed by white base glaze, and the uneven thickness of the glaze layer and the adsorption of volatiles are used to form decoration through kiln change; transparent glaze is applied and fired to make the decoration under the glaze. The glaze surface is bright and elegant. The white base glaze under the transparent glaze layer is like drawing paper, and irregular patterns of kiln change are presented on it, with hazy water splashes, glaze bubbles, and smoke, which are both random and interesting, like color but not color, and like kiln change. Kiln change transforms the common process defects of ordinary pottery products into defective beauty on the white base glaze, achieving beneficial effects such as beauty and hygiene; 3. The present invention solves the problems of too many impurities in ceramic products and difficulty in decorating the body parts at a low cost, and produces ceramic products with underglaze decoration, which is conducive to the development of ceramics into fine ceramics for daily use and art. DETAILED DESCRIPTION

[0007] A method for preparing an underglaze decorative ceramic product, characterized in that it comprises the following process steps (1) Billet preparation ①Formula of blank: Take the following materials by weight percentage Pottery clay 55%, feldspar 18%, quartz 10%, panning mud 17%; ②Blank preparation The process is carried out according to a conventional method for preparing blanks for producing ceramic products, and the blanks for producing ceramic products are prepared for use; (2) Preparation of white base glaze ①White base glaze formula: Take the following materials by weight percentage: Quartz 13%, limestone 9%, feldspar 19%, black mud 10%, talc 7%, barium carbonate 5%, zinc oxide 7%, zircon powder 10%, frit 20%; The frit is composed of the following materials: by weight: quartz 28%, feldspar 23%, borax 16%, zinc oxide 8%, zircon 11%, calcium carbonate 10%, potassium nitrate 4%; Preparation of the frit: mixing the materials in the formula, smelting them and quenching them with water to obtain a crystalline block; ② Preparation of white base glaze The above raw materials are mixed and then added with clean water for ball milling. After ball milling, the raw materials are passed through an iron remover for iron removal. The iron-removed raw materials are sieved with 200 meshes. The sieved raw materials are mixed with clean water and prepared into a glaze slurry with a concentration of 38 degrees Baume for standby use. (3) Preparation of green transparent glaze ①Green transparent glaze formula: Take the following materials by weight percentage: Kaolin 10%, quartz 18%, feldspar 11%, dolomite 4%, calcite 5.5%, copper carbonate 1%, barium chromate 0.5%, frit 50%; The frit is composed of the following materials: by weight percentage: 11% kaolin, 15% limestone, 17% feldspar, 22% borax, 24% quartz, and 11% soda ash; Preparation of the frit: mixing the materials in the formula, smelting them and quenching them with water to obtain a crystalline block; ② Preparation of green transparent glaze The above raw materials are mixed and then added with clean water for ball milling. After ball milling, the raw materials are passed through an iron remover for iron removal. The iron-removed raw materials are sieved with 200 meshes. The sieved raw materials are mixed with clean water and prepared into a glaze slurry with a concentration of 32 degrees Baume for standby use. (4) Molding and trimming of ceramic parts The above-mentioned blank is molded according to a conventional molding method for ceramic tires to prepare a ceramic tire; the ceramic tire is naturally dried for 8-12 hours, and the surface of the ceramic tire is trimmed by using bamboo pieces, brushes, soft cloth and clean water to remove the mold lines and make the surface flat and smooth; the trimmed ceramic tire is naturally dried for 24-36 hours; (5) Applying base glaze to ceramic parts The above-mentioned white base glaze is used for glazing; before glazing, the ceramic body is placed on a small platform rotating slowly, and a small spray gun is used to add clean water to spray water intermittently on the surface of the rotating ceramic body, and the area of ​​the ceramic body surface sprayed with water accounts for 20-30% of the total area of ​​the ceramic body surface; the ceramic body sprayed with water is immediately placed in a glaze liquid pool for dipping, and the dipping time is 2-3 seconds; the glazed ceramic body is naturally dried for 10 hours; (6) Sintering of ceramic parts The ceramic body parts with white base glaze are sintered in a kiln for ceramic production at a temperature of 810°C for 7 hours in an oxidizing atmosphere. The products out of the kiln are white ceramic products. (7) Applying glaze to ceramic products The green transparent glaze is used to glaze the sintered ceramic products by manual dipping, the dipping time is 3-4 seconds, and the glazed ceramic products are naturally dried for 8-12 hours; (8) Firing of ceramic products The ceramic products with glaze applied are fired in a kiln used for ceramic production; the firing time is 10-12 hours, the firing temperature is 1170°C, and the firing atmosphere is an oxidizing atmosphere; the fired products become fine ceramic pottery, which is also a disguised underglaze decorative ceramic product.

[0008] The purpose of the following comparative examples is to enhance the understanding of the patent's innovative points Comparative Example 1 The difference from the embodiment is that: before applying the white base glaze, the surface of the ceramic body is not sprayed with water. When the white base glaze is applied, there will be no uneven glaze absorption thickness due to uneven humidity on the body surface. Under the vitrified glaze layer after firing, there is no local thin glaze of the base glaze and a water splash pattern of the body color can be seen.

[0009] Comparative Example 2 The difference from the embodiment is that the tire is not sintered to discharge impurities. When the tire is fired, a large amount of impurities will decompose and volatilize, resulting in a large number of defects in the glaze layer of the product surface, which cannot meet the requirements of fine ceramic products.

[0010] Comparative Example 3 The difference from the embodiment is that the body is not coated with white base glaze, and the surface of the body after firing appears dark red or dark gray, which is the original color of ordinary pottery, affecting the decorative effect of the product.

[0011] Comparative Example 4 The difference from the embodiment is that the body is not sintered after the white base glaze is applied, but is fired after the transparent top glaze is applied on top. The volatiles generated by the body during the firing process pollute and destroy the transparent top glaze layer, resulting in unqualified products.

[0012] Comparative Example 5 The difference from the embodiment is that the body is fired once after the white base glaze is applied, and no transparent top glaze is applied, so the underglaze decorative effect of kiln-fired products under the transparent top glaze cannot be produced. For example, small pores in the glaze layer will not become small glaze bubbles, and the overall appearance smoothness of the product is poor.

Claims

1. A method for preparing an underglaze decorative ceramic product, characterized in that: The process steps include: (1) Billet preparation ①Formula of blank: Take the following materials by weight percentage: Pottery clay 52-58%, feldspar 16-20%, quartz 8-12%, panning mud 15-19%; ②Blank preparation: The process is carried out according to a conventional method for preparing blanks for producing ceramic products, and the blanks for producing ceramic products are prepared for use; (2) Preparation of white base glaze ①White base glaze formula: Take the following materials by weight percentage: Quartz 11-15%, limestone 8-10%, feldspar 17-20%, black mud 8-12%, talc 6-8%, barium carbonate 4-6%, zinc oxide 6-8%, zircon powder 8-12%, frit 18-22%; The frit is composed of the following materials: by weight: quartz 26-30%, feldspar 22-24%, borax 15-18%, zinc oxide 7-9%, zircon 10-12%, calcium carbonate 9-12%, potassium nitrate 3-5%; Preparation of the frit: mixing the materials in the formula, smelting them and quenching them with water to obtain a crystalline block; ② Preparation of white base glaze: The above raw materials are mixed and then added with clean water for ball milling. After ball milling, the raw materials are passed through an iron remover for iron removal. The iron-removed raw materials are sieved with 200 meshes. The sieved raw materials are mixed with clean water and prepared into a glaze slurry with a concentration of 38 degrees Baume for standby use. (3) Preparation of green transparent glaze: ①Green transparent glaze formula: Take the following materials by weight percentage: Kaolin 9-12%, quartz 16-19%, feldspar 10-12%, dolomite 3-5%, calcite 4.5-6.5%, copper carbonate 0.8-1.2%, barium chromate 0.4-0.6%, frit 48-52%; The frit is composed of the following materials: by weight percentage: 10-12% kaolin, 14-16% limestone, 16-18% feldspar, 20-24% borax, 22-26% quartz, and 10-12% soda ash; Preparation of the frit: mixing the materials in the formula, smelting them and quenching them with water to obtain a crystalline block; ② Preparation of green transparent glaze The above raw materials are mixed and then added with clean water for ball milling. After ball milling, the raw materials are passed through an iron remover for iron removal. The iron-removed raw materials are sieved with 200 meshes. The sieved raw materials are mixed with clean water and prepared into a glaze slurry with a concentration of 32 degrees Baume for standby use. (4) Molding and trimming of ceramic parts The above-mentioned blank is molded according to a conventional molding method for ceramic tires to prepare a ceramic tire; the ceramic tire is naturally dried for 8-12 hours, and the surface of the ceramic tire is trimmed by using bamboo pieces, brushes, soft cloth and clean water to remove the mold lines and make the surface flat and smooth; the trimmed ceramic tire is naturally dried for 24-36 hours; (5) Applying base glaze to ceramic parts The above-mentioned white base glaze is used for glazing; before glazing, the ceramic body is placed on a small platform rotating slowly, and a small spray gun is used to add clean water to spray water intermittently on the surface of the rotating ceramic body, and the area of ​​the ceramic body surface sprayed with water accounts for 20-30% of the total area of ​​the ceramic body surface; the ceramic body sprayed with water immediately enters the glaze liquid pool for glazing, and the glazing time is 2-3 seconds; the glazed ceramic body is naturally dried for 8-12 hours; (6) Sintering of ceramic parts The ceramic body with white base glaze is sintered in a kiln for ceramic production at a temperature of 800-820°C for 6-8 hours in an oxidizing atmosphere. The products out of the kiln are white ceramic products. (7) Applying glaze to ceramic products The green transparent glaze is used to glaze the sintered ceramic products by manual dipping, the dipping time is 3-4 seconds, and the glazed ceramic products are naturally dried for 8-12 hours; (8) Firing of ceramic products The ceramic products with glaze applied are fired in a kiln for ceramic production; the firing time is 10-12 hours, the firing temperature is 1160-1180°C, and the firing atmosphere is an oxidizing atmosphere; the fired products become fine ceramic pottery, which is also a disguised underglaze decorative ceramic product.