Double-layer fancy glaze with chapped ground texture and preparation method of double-layer fancy glaze

Abstract

The invention discloses double-layer fancy glaze with chapped ground texture and a preparation method of the double-layer fancy glaze, and relates to the technical field of ceramic glaze. The double-layer fancy glaze is composed of a ground glaze layer and a cover glaze layer. The ground glaze raw materials comprise potassium feldspar, kaolin, calcite, quartz, dolomite, zinc oxide and pigment; the cover glaze raw materials comprise potassium feldspar, waste porcelain powder, blank powder, chinastone, limestone, sepiolite, quartz, zirconium silicate with the particle size D50 being less than or equal to 1.0 mu m and pigment. The preparation method comprises the following steps: respectively carrying out ball milling to prepare ground glaze slip (32-40 baume degrees) and cover glaze slip (51-53 baume degrees); spraying ground glaze on the green body, drying, and then soaking with cover glaze; and finally, sintering at the temperature of 1250-1270 DEG C in a reducing atmosphere. Through the synergistic effect of the sepiolite and other components, the cover glaze has high surface tension, forms a microcrack network during drying, generates controllable glaze shrinkage during firing, forms a three-dimensional chap texture with crack width of 1-5mm and strong curled and raised crack edges, and meanwhile, the ground glaze completely covers a green body, so that the product practicability is ensured.

Description

Technical Field

[0001] This invention relates to the field of ceramic glaze technology, specifically to a method for preparing a double-layer floral glaze that forms a three-dimensional texture mimicking the dry, cracked surface of the earth by actively controlling the surface tension of the glaze layer through glaze formulation and process design. Background Technology

[0002] In ceramic decorative art, glaze texture is an important means of shaping the visual and tactile quality of a work. Traditional crackle glazes, such as ice crackle and gold thread and iron wire, are mainly formed by the stress generated during cooling due to the difference in the coefficients of thermal expansion between the glaze and the body. The cracks are usually fine, evenly networked, and have smooth edges.

[0003] In pursuit of a more visually striking blocky crack effect, existing technologies have explored various approaches. For example, Chinese patent document CN103553714A discloses "a glaze with a cracked effect," which employs a three-layer composite structure of base glaze, middle glaze, and top glaze, utilizing the shrinkage differences between the layers to create cracks. While this method can achieve larger cracks, it has significant drawbacks: First, the three-stage glazing process is complex, resulting in low production efficiency and high costs; second, the exposed body at the crack points leads to a significant decrease in the product's water resistance, wear resistance, and other physical properties, making it prone to accumulating dirt and grime, thus greatly limiting its application in fields requiring high cleanliness, such as daily-use ceramics and sanitary ware.

[0004] Another common technical approach is to use phase-separated opaque glazes, such as the scheme involved in Chinese patent document CN106431172A. This approach involves formulating base glazes and top glazes with different chemical compositions, utilizing the liquid phase separation of the glaze melt at high temperatures to produce changes in color and texture. However, the core mechanism of this technology lies in the optical effects brought about by thermodynamic phase separation or chemical reactions, rather than aiming to form a specific three-dimensional cracked texture through physical shrinkage. Therefore, it cannot achieve the natural cracking effect of curled and raised edges and wide and deep cracks.

[0005] Therefore, developing a ceramic glaze with a relatively simple process that can ensure the integrity of the blank and stably form a strong three-dimensional cracked texture, and its preparation method, has important technical and artistic value. Summary of the Invention

[0006] The present invention aims to overcome the above-mentioned shortcomings of the prior art and provide a double-layer floral glaze with earth-crack texture that is simple to process, has a unique texture effect, and completely protects the body, as well as its preparation method.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A double-layer floral glaze with a cracked earth texture consists of a base glaze layer covering the surface of the ceramic body and a top glaze layer applied on top of the base glaze layer.

[0009] The raw materials of the base glaze, by weight, include: 30-40 parts potassium feldspar, 5-10 parts kaolin, 10-20 parts calcite, 20-28 parts quartz, 2-7 parts dolomite, 2-6 parts zinc oxide, and 0-12 parts high-temperature ceramic pigment; the raw materials of the top glaze, by weight, include: 20-30 parts potassium feldspar, 8-15 parts waste porcelain powder, 10-16 parts body powder, 10-15 parts porcelain stone, 5-10 parts limestone, 5-10 parts sepiolite, 5-10 parts quartz, 2-6 parts zirconium silicate, and 0-10 parts high-temperature ceramic pigment; wherein the particle size D50 of the zirconium silicate is ≤1.0μm.

[0010] Preferably, the sepiolite content in the glaze is 8-10 parts by weight.

[0011] In this invention, the synergistic mechanism of the key components of the glaze formula is the core of achieving the invention's objective:

[0012] 1. Sepiolite plays a dual crucial role. Firstly, as a magnesium-rich mineral, the introduced magnesium oxide effectively increases the surface tension of the glaze melt. Secondly, its unique fibrous structure endows the glaze slurry with high water retention, and together with the body powder, it significantly increases the drying shrinkage rate of the glaze layer, thus forming a uniform and dense network of drying cracks on the glaze surface before firing in the kiln. This network provides a predetermined starting point and path for the subsequent high-temperature stage glaze melt shrinkage behavior based on high surface tension, which is a prerequisite for obtaining a uniform and controllable crack texture.

[0013] 2. Fine-grained zirconium silicate, while increasing the high-temperature viscosity of the glaze melt, also contributes to the increase in surface tension. Its high viscosity effect effectively "locks in" the curled-up, raised shape formed after the cracks shrink, preventing it from leveling out at high temperatures and ensuring a three-dimensional appearance;

[0014] 3. Waste porcelain powder is used to increase the initial melting temperature of the glaze and broaden its melting range, so that the surface glaze can maintain a certain strength and shape stability at higher temperatures, without excessive softening and flow, which is conducive to the fixation and maintenance of the final three-dimensional texture.

[0015] 4. Porcelain stone and quartz provide the silica and alumina needed to form the glaze glass network framework, ensuring the glaze has a suitable high-temperature viscosity;

[0016] 5. Limestone acts as a flux, decomposing at high temperatures to release carbon dioxide gas. This minute gas escape process helps promote the separation and shrinkage of the glaze layer.

[0017] The present invention also provides a method for preparing the double-layer glaze, comprising the following steps:

[0018] Step 1. Weighing raw materials: Weigh each raw material according to the above formulas for the base glaze and top glaze;

[0019] Step 2. Glaze preparation:

[0020] a) Preparation of base glaze slurry: Add the base glaze raw materials, ball milling media, and water to a ball mill at a mass ratio of 1:2.5:0.6. After rapid ball milling for 8-13 minutes, pass the slurry through a 200-mesh sieve, controlling the residue to ≤0.15%. Then adjust the glaze slurry concentration to 32-40 Baume degrees.

[0021] b) Preparation of the glaze slurry: Add the glaze raw materials, milling media, and water to a ball mill at a mass ratio of 1:3:0.6. Mill rapidly for 13-15 minutes, then pass through a 200-mesh sieve, ensuring the residue is ≤0.3%. Adjust the glaze slurry concentration to 51-53 Baume degrees.

[0022] Step 3. Glazing:

[0023] a) Applying the base glaze: Apply the base glaze slurry to the surface of the bisque-fired body using a spray glaze method, controlling the thickness of the base glaze layer to be 0.4~0.7 mm, and then dry it;

[0024] b) Applying the top glaze: After the base glaze layer is completely dry, apply the top glaze slurry using the dipping method, controlling the thickness of the top glaze layer to be 1.0~1.3 mm;

[0025] Step 4. Firing: Place the glazed body into the kiln and fire it in a reducing atmosphere at a firing temperature of 1250~1270℃. Hold it at the highest temperature for 20 minutes, and then let it cool naturally to room temperature to obtain the finished product.

[0026] Preferably, in step 2, when adjusting the glaze concentration, fairy water is added for preparation.

[0027] Preferably, in step 3, the thickness of the base glaze layer is 0.6~0.7 mm, and the thickness of the top glaze layer is 1.2~1.3 mm.

[0028] Preferably, in step 4, the firing temperature is 1260~1270℃.

[0029] The beneficial effects of this invention are as follows:

[0030] 1. Unique and controllable texture effect: This invention creatively uses a formula design with sepiolite as the core to synergistically regulate the chemical properties (high surface tension) and physical state (pre-formed drying crack network) of the glaze, actively inducing a controllable "glaze shrinkage" phenomenon, successfully obtaining a texture that mimics the cracks of the earth with a crack width of 1~5 mm, a crack thickness of 0.8~1.2 mm, and strong curling and bulging edges. The maximum crack width and three-dimensionality far exceed those of traditional crack glazes.

[0031] 2. Simplified process and high practicality: Only two layers of glaze are required, the base and the top, making the process simple and efficient. The base glaze completely covers and seals the body, thoroughly solving the problems of reduced strength, leakage, and hygiene hazards caused by exposed body in cracked glaze products. This allows the artistic glaze to be safely applied to fields with strict requirements for physical properties and hygiene standards, such as daily-use porcelain, building ceramics, and sanitary ware.

[0032] 3. Rich decorative expression: Various high-temperature pigments can be added independently to the base glaze and the top glaze. After firing, the color of the base layer shines through the wide cracks of the top glaze, forming a sharp contrast and rich color layers with the main color of the top glaze, which greatly expands the expressive forms of ceramic art. Attached Figure Description

[0033] Figure 1 This is a partial glaze effect image of the ceramic product obtained in Embodiment 1 of the present invention;

[0034] Figure 2 This is a partial glaze effect image of the ceramic product obtained in Embodiment 2 of the present invention;

[0035] Figure 3 This is a partial glaze effect image of the ceramic product obtained in Embodiment 3 of the present invention;

[0036] Figure 4 This is a partial glaze effect image of the ceramic product obtained in Example 4 of the present invention;

[0037] Figure 5 This is a partial glaze effect diagram of the ceramic product obtained in Comparative Example 1 (without base glaze) of the present invention;

[0038] Figure 6 This is a partial glaze effect diagram of the ceramic product prepared in Comparative Example 2 of the present invention (the glaze does not contain sepiolite);

[0039] Figure 7 This is a diagram of the complete ceramic product obtained in Example 4 of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below with reference to embodiments and comparative examples. In the raw materials used in the embodiments, zinc oxide, zirconium silicate, and high-temperature ceramic pigments are commercially available industrial-grade products. The typical chemical compositions of the remaining ceramic raw materials are shown in Table 1.

[0041] Table 1 Chemical composition of main raw materials (mass percentage, %)

[0042] raw material <![CDATA[SiO2]]> <![CDATA[Al2O3]]> CaO MgO <![CDATA[K2O]]> <![CDATA[Na2O]]> <![CDATA[Fe2O3]]> <![CDATA[TiO2]]> IL sepiolite 52.26 2.05 2.18 21.11 0.48 0.08 0.40 0 21.44 Potassium feldspar 65.8 18.23 0.14 0.01 11.75 3.56 0.37 0.01 0.25 Waste porcelain powder 70.05 19.5 1.2 0.8 3.5 2.51 1.34 0.35 0 Dazhou Town Quartz 98.3 0.6 0 0 0.03 0 0.07 0 0.33 Kaolin 47.2 36.35 0.49 0.18 0 0.4 0.83 0 15.22 dolomite 0.56 0 33.58 19.6 0 0 0.15 0 44.02 calcite 0.46 0.27 56.1 0.78 0.02 0.62 0.03 0.01 41.18 Three Treasures Spreading Powder 69.27 20.28 0.81 0.21 2.98 1.51 0.72 0.06 4.16 Qimen porcelain stone 66.13 20.64 1.23 0.02 3.10 3.15 0.77 0.04 2.27 Gemstone Grey 3.26 0.58 50.17 1.21 0.16 0.69 0.19 0.03 43.71

[0043] Example 1

[0044] Weigh the following raw materials by weight: 35 parts potassium feldspar, 10 parts kaolin, 10 parts calcite, 24 parts Dazhou Town quartz, 7 parts dolomite, 6 parts calcined zinc oxide, and 10 parts high-temperature ceramic orange-yellow pigment; weigh the following raw materials by weight: 30 parts potassium feldspar, 15 parts waste porcelain powder, 16 parts Sanbao Peng clay powder, 10 parts Qimen porcelain stone, 10 parts Tianbao limestone, 5 parts sepiolite, 10 parts Dazhou Town quartz, and 6 parts zirconium silicate with a particle size D50 of 0.8 micrometers; ball mill the raw materials of the base glaze at a mass ratio of material:ball:water = 1:2.5:0.6, and after 10 minutes, remove from the mill and pass through a 200-mesh sieve. Then, sap is added to prepare a glaze slurry with a Baume degree of 40. The base glaze slurry is sprayed onto the bisque-fired body, controlling the glaze layer thickness to be about 0.7 mm, and then dried in a drying oven. The surface glaze raw materials are ball-milled for 14 minutes at a mass ratio of material:ball:water = 1:3:0.6, passed through a 200-mesh sieve, and sap is added to prepare a glaze slurry with a Baume degree of 53. The surface glaze slurry is applied to the dried base glaze layer using the glazing method, controlling the surface glaze layer thickness to be about 1.3 mm. After the surface glaze dries, the body is placed in a gas kiln and fired at 1270℃ in a reducing atmosphere, holding at the highest temperature for 20 minutes, and then cooled to obtain the finished product.

[0045] The resulting products are as follows Figure 1 As shown, the orange-yellow base glaze completely covers the body, while the white surface glaze cracks to form independent cracks with distinct upward curling edges. The crack width is 1-3.8 mm, and the crack thickness is about 1.2 mm. Overall, it presents a deep, three-dimensional texture of earth cracks with a significant sense of concavity and convexity.

[0046] Examples 2 to 4

[0047] To demonstrate the adjustability and universality of the formulation and process of this invention, the following three embodiments were implemented, and their specific formulations and key process parameters are shown in Table 2:

[0048] Table 2. Formulations and process parameters for Examples 2 to 4

[0049] project Example 2 Example 3 Example 4 Base glaze raw materials (parts by weight) Potassium feldspar 40, kaolin 5, calcite 20, Dazhou Town quartz 20, dolomite 7, calcined zinc oxide 5, and bright red pigment 12 Potassium feldspar 30, kaolin 8, calcite 18, Dazhou Town quartz 28, dolomite 2, calcined zinc oxide 2, and bright red pigment 10 Potassium feldspar 36, kaolinite 7, calcite 12, Dazhou Town quartz 24, dolomite 5, calcined zinc oxide 6, orange-red pigment 11 Glaze raw materials (parts by weight) Potassium feldspar 25, waste porcelain powder 12, Sanbao slab powder 15, Qimen porcelain stone 14, Tianbao grey stone 5, sepiolite 8, Dazhou Town quartz 5, zirconium silicate 5, light blue pigment 10 Potassium feldspar 20g, waste porcelain powder 8g, Sanbao Peng clay powder 10g, Qimen porcelain stone 15g, Tianbao limestone 10g, sepiolite 10g, Dazhou Town quartz 10g, zirconium silicate 2g Potassium feldspar 26, waste porcelain powder 12, Sanbao Peng clay powder 15, Qimen porcelain stone 13, Tianbao limestone 6, sepiolite 9, Dazhou Town quartz 6, zirconium silicate 5, green material 10 Baume scale of base glaze 35°Bé 32°Bé 38°Bé Baume scale of surface glaze 51°Bé 51°Bé 52°Bé Base glaze thickness 0.6 mm 0.4 mm 0.6 mm glaze thickness 1.1 mm 1.0 mm 1.3 mm Firing temperature 1270℃ 1250℃ 1260℃

[0050] The glaze preparation and glazing process of Examples 2, 3 and 4 were carried out in accordance with Example 1. The glaze slurries were all ball-milled, passed through a 200-mesh sieve, and then mixed with water to adjust to the corresponding Baumé degree in Table 2.

[0051] The products obtained after firing are as follows: Figure 2 , Figure 3 , Figure 4 As shown, each embodiment successfully achieved the effect of complete coverage of the base glaze and uniform cracking and curling of the top glaze layer. The crack width is in the range of 1 to 5 mm, the crack thickness is 0.8 to 1.2 mm, the texture is natural, the three-dimensional effect is strong, and the color matching of the base and top glaze presents a rich variety of artistic effects.

[0052] Comparative Example 1 (without base glaze layer)

[0053] To verify the necessity of the base glaze layer, this comparative example was set up. Its top glaze formula contained 10 parts pink pigment, and the remaining raw materials were exactly the same as in Example 1, but no base glaze was applied. All other process parameters, including glaze fineness, Baumé degree, glaze thickness, and firing regime, remained consistent with Example 1.

[0054] The effect of the product after firing is as follows Figure 5 As shown, due to the lack of a base glaze layer, the surface glaze melt is in direct contact with the body, and its shrinkage behavior caused by high surface tension is severely hindered. As a result, the glaze surface cracks are messy, with large areas of cracks sticking together and accumulating, unable to spread out. The crack width is only about 1 mm and most of them are not smooth. The cracks are abnormally thick (about 3 mm). The body is completely exposed at the cracks and fails to form any smooth and clear crack texture. This comparison proves that a complete base glaze layer is a necessary foundation for the surface glaze to shrink freely and form an ideal texture.

[0055] Comparative Example 2 (The glaze does not contain sepiolite)

[0056] To verify the irreplaceable role of sepiolite in achieving the texture of this invention, this key comparative example was set up. Its surface glaze formula did not contain sepiolite; its base glaze formula replaced the bright red pigment with a dark blue pigment; all other preparation and firing process parameters were strictly the same as in Example 2.

[0057] The effect of the product after firing is as follows Figure 6 As shown, the glaze surface in this comparative example exhibits irregular cracking, with extremely uneven distribution of cracks of varying sizes. Most cracks are semi-adhered and flat, lacking any curling or bulging at the edges. The cracks are narrow (mostly less than 1 mm) and discontinuous, resulting in a messy and flat overall effect, unlike Examples 1-4. Figure 1-4 The three-dimensional effect of "earth fissures" presented by the original is vastly different from that of the original, which features wide fissures (3-5 mm), full and curled cracks, and a natural and orderly texture.

[0058] Experimental observations revealed that after drying, the surface of the glaze in this comparative example only exhibited scattered and disordered microcracks, failing to form a uniform and continuous microcrack network like in Examples 1-4. Furthermore, the cracks formed after firing in this comparative example were merely ordinary cracks caused by stress release during the initial drying and firing stages of the glaze, rather than the three-dimensional texture formed by the shrinkage of the glaze melt driven by high surface tension as claimed in this invention. The reason for this is that the glaze in this comparative example lacked the key raw material sepiolite, resulting in significantly insufficient surface tension of the melt during the high-temperature melting stage. This insufficient force could not provide enough momentum for the glaze melt to shrink inward along the edges of the initial cracks. Consequently, the glaze melt failed to shrink and curl fully on the surface of the base glaze, resulting in no curling or bulging at the edges of the cracks, presenting a flat state that adhered to the base glaze. Correspondingly, due to the lack of sufficient shrinkage driving force to fully "pull apart" the glaze melt from the cracks, the final cracks were narrow, disordered, and could not achieve the wide and uniform crack effect of 1-5 mm achieved in this invention.

[0059] This result strongly demonstrates that sepiolite, through its unique synergistic effect of chemical (providing MgO) and physical (fiber structure leading to high drying shrinkage), is an essential key component for forming uniform drying crack initiation points and ultimately obtaining the desired three-dimensional cracked texture. Its role cannot be simply replaced by ordinary magnesium-containing raw materials.

[0060] In summary, this invention, through the creative selection and mechanism design of the glaze formula, especially the key components such as sepiolite, combined with matching glaze slurry process parameters (fineness, Baumé degree, thickness), has successfully developed a double-layer floral glaze capable of stably forming a unique earth-crack texture and its efficient preparation method. This method effectively solves the defect of exposed body in traditional crack glaze technology and greatly expands the application space of three-dimensional crack texture in ceramic products.

[0061] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A double-layered floral glaze with a cracked earth texture, characterized in that: It includes a base glaze layer covering the surface of the ceramic body and a top glaze layer applied on top of the base glaze layer; The raw materials of the base glaze, by weight, include: 30-40 parts potassium feldspar, 5-10 parts kaolin, 10-20 parts calcite, 20-28 parts quartz, 2-7 parts dolomite, 2-6 parts zinc oxide, and 0-12 parts high-temperature ceramic colorant. The raw materials of the glaze, by weight, include: 20-30 parts potassium feldspar, 8-15 parts waste porcelain powder, 10-16 parts body powder, 10-15 parts porcelain stone, 5-10 parts limestone, 5-10 parts sepiolite, 5-10 parts quartz, 2-6 parts zirconium silicate, and 0-10 parts high-temperature ceramic colorant; wherein the particle size D50 of the zirconium silicate is ≤1.0μm.

2. The double-layered floral glaze with a cracked texture as described in claim 1, characterized in that: The sepiolite content in the glaze is 8-10 parts by weight.

3. A method for preparing a double-layered floral glaze with a cracked texture as described in claim 1 or 2, characterized in that, Includes the following steps: Step 1. Weighing raw materials: Weigh each raw material according to the formulas for the base glaze and the top glaze; Step 2. Glaze preparation: a) Preparation of base glaze slurry: Add the base glaze raw materials, ball milling media and water into the ball mill at a mass ratio of 1:2.5:0.6, ball mill quickly for 8-13 minutes, then pass through a 200-mesh sieve, controlling the sieve residue to ≤0.15%, and then adjust the glaze slurry concentration to 32-40 Baume degrees. b) Preparation of surface glaze slurry: Add the surface glaze raw materials, ball milling media and water into the ball mill at a mass ratio of 1:3:0.6, ball mill quickly for 13-15 minutes, then pass through a 200-mesh sieve, controlling the sieve residue to ≤0.3%, and then adjust the glaze slurry concentration to 51-53 Baume degrees. Step 3. Glazing: a) Applying the base glaze: The base glaze slurry is applied to the surface of the bisque-fired body using a spray glazing method, controlling the thickness of the base glaze layer to be 0.4~0.7 mm, and then dried; b) Applying the top glaze: After the base glaze layer is completely dry, apply the top glaze slurry using the dipping method, controlling the thickness of the top glaze layer to be 1.0~1.3 mm; Step 4. Firing: Place the glazed body into the kiln and fire it in a reducing atmosphere at a firing temperature of 1250~1270℃. Hold it at the highest temperature for 20 minutes, and then let it cool naturally to room temperature to obtain the finished product.

4. The preparation method according to claim 3, characterized in that: In step 2, when adjusting the glaze concentration, fairy water is added for preparation.

5. The preparation method according to claim 3, characterized in that: In step 3, the thickness of the base glaze layer is 0.6~0.7 mm, and the thickness of the top glaze layer is 1.2~1.3 mm.

6. The preparation method according to claim 3, characterized in that: In step 4, the firing temperature is 1260~1270℃.

Images