Soda-fired gradually-changed fused glaze ceramic and preparation method thereof

Abstract

The invention relates to the technical field of ceramics, in particular to soda-fired gradually-changed fused glaze ceramic and a preparation method thereof.The soda-fired gradually-changed fused glaze ceramic is characterized in that one side of cover glaze of the soda-fired gradually-changed fused glaze ceramic presents purple red stripes, the other side of the cover glaze presents black brown stripes, and a middle transition area presents yellowish brown stripes; the cover glaze is prepared from the following raw materials in parts by weight: 10 to 15 parts of clay, 35 to 45 parts of silicon dioxide, 15 to 20 parts of calcite, 10 to 15 parts of forsterite, 8 to 12 parts of ferrodolomite and 10 to 14 parts of purple frit. The black brown stripes on one side form a special carbon granule mottle texture of firewood firing due to carbon powder and wood powder residues, the purple red stripes on the other side form vitreous luster due to purple frits and soda firing, and a middle yellowish-brown transition area has semi-matte texture and transparency, so that natural transition of colors is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramics, and in particular to soda-fired gradient fused glaze ceramics and a preparation method thereof. Background Art

[0002] In traditional ceramic decoration technology, color patterns are achieved through manual painting or printing. However, due to problems such as pigment boundary solidification and poor diffusion at the junction of different colors, mechanical and rigid boundaries are often formed, or due to fluctuations in the kiln atmosphere, the transition area may have color discontinuities and uneven spots. In the existing technology, some schemes try to achieve a gradient effect through segmented glazing or local chemical colorants, but there are the following defects: complex process: relying on multiple painting processes, high labor costs and low efficiency; poor color controllability: the color level change in the transition area is difficult to accurately control and is easily affected by the thickness of the glaze layer and the firing temperature; single coloring mechanism: mainly through physical mixing of pigments or limited metal ions (such as Co 2+ 、Cu 2+ ) color development, lacking a chemical valence transformation mechanism based on the synergy between mineral raw materials and kiln atmosphere, resulting in an inadequate natural transition effect. Therefore, a process is urgently needed that utilizes the synergistic effect of a controlled atmosphere and mineral raw materials, taking advantage of the valence gradient transformation of metal ions in the glaze, combined with the melt diffusion characteristics of fluxing minerals, to achieve a natural gradient of glaze color, fundamentally solving the problem of the harsh boundaries of traditional colored painting. Summary of the Invention

[0003] An object of the present invention is to solve at least the above-mentioned problems by soda-fired gradient fused glaze ceramics and a method for preparing the same.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is as follows: soda-fired gradient fused glaze ceramics, including a body and a glaze, one side of the glaze presents purple-red stripes, the other side presents black-brown stripes, and the middle transition area presents yellow-brown stripes.

[0005] Preferably, the glaze comprises the following raw materials in parts by weight: 10-15 parts of clay, 35-45 parts of silicon dioxide, 15-20 parts of calcite, 10-15 parts of forsterite, 8-12 parts of ankerite, and 10-14 parts of purple frit.

[0006] Preferably, the purple frit comprises the following raw materials in parts by weight: 50-60 parts of spodumene, 15-20 parts of potassium feldspar, 10-15 parts of bauxite, 10-15 parts of quartz, 3-5 parts of red iron oxide, 2-3 parts of manganese oxide, 3-5 parts of fluorite, and 2-3 parts of sodium carbonate.

[0007] Preferably, the green body comprises the following raw materials in parts by weight: 40-50 parts of kaolin, 20-30 parts of quartz, and 15-25 parts of feldspar.

[0008] The method for preparing the soda-fired gradient fused glaze ceramic comprises the following steps:

[0009] Step a, forming a green body and drying it;

[0010] Step b, applying glaze on the body;

[0011] Step c: glaze firing in the kiln, first introduce the carbon salt mixture from one side of the kiln, then switch to introducing the soda mixture from the other side of the kiln;

[0012] Step d: taking the ceramic out of the kiln to obtain the soda-fired gradient fused glaze ceramic.

[0013] Preferably, in step c, the firing curve is as follows:

[0014] Heating stage 1: from room temperature to 300°C, heating rate 5°C / min;

[0015] Heating stage 2: from 300°C to 800°C, heating rate 8°C / min, maintaining oxidizing atmosphere;

[0016] Heating stage 3: from 800°C to 1150°C, heating rate 3°C / min, maintaining oxidizing atmosphere;

[0017] Insulation stage: total duration 3h;

[0018] Cooling stage 1: from 1150℃ to 800℃, natural cooling, rate ≤10℃ / min;

[0019] Cooling in 2 stages: from 800°C to room temperature, with the door open for air cooling.

[0020] Preferably, in step c, a first powder spraying port and a first air outlet are provided on one side of the kiln, and a second powder spraying port and a second air outlet are provided on the opposite side;

[0021] The insulation stage includes:

[0022] 0-60min: Close the first air outlet, spray the carbon-salt mixed powder into the kiln from the first powder spraying port, and exhaust from the second air outlet. The glaze surface of the ceramic facing the first powder spraying port is smoked black by the carbon-salt mixed powder to form dark brown spots;

[0023] 60-120min: First, briefly open the air outlets on both sides to balance the air pressure for 5 minutes, then close the second air outlet, spray soda mixture into the kiln from the second powder spraying port, and exhaust from the first air outlet. The glaze surface of the ceramic facing the second powder spraying port will be smoked into reddish-purple stripes by the soda mixture;

[0024] 120-180min: Keep warm and continue glaze firing.

[0025] Preferably, in step c, the carbon-salt mixed powder comprises the following raw materials in parts by weight: 50-60 parts of carbon powder, 40-50 parts of wood powder, 7-9 parts of salt powder, and 10-12 parts of red iron oxide powder.

[0026] Preferably, in step c, the soda powder mixture comprises the following raw materials in parts by weight: 80-90 parts of purple frit powder, 40-50 parts of soda ash, 5-8 parts of fluorite, and 5-8 parts of apatite.

[0027] Preferably, the preparation method of the purple frit powder is as follows: the raw material components of the purple frit are mixed in proportion and ball-milled, after high-temperature melting, the melt is quickly poured into water for quenching to form glassy fragments, and then ground into purple frit powder by a ball mill.

[0028] From the above description, it can be seen that the soda-fired gradient fused glaze ceramics and the preparation method thereof provided by the present invention have the following beneficial effects: the black-brown markings on the left side have a mottled texture of carbon particles unique to wood-fired fire due to the residual charcoal powder and wood powder, the purple-red markings on the right side have a glassy luster due to the purple frit and soda firing, and the yellow-brown transition zone in the middle has both a semi-matte texture and a transparent feeling, achieving a natural transition of colors. DETAILED DESCRIPTION

[0029] The present invention is further described below through specific embodiments.

[0030] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0031] The soda-fired gradient fused glaze ceramics of the present invention comprise a body and a surface glaze. One side of the surface glaze presents purple-red stripes, the other side presents black-brown stripes, and the middle transition area presents yellow-brown stripes.

[0032] The glaze comprises the following raw materials in parts by weight: 10-15 parts of clay, 35-45 parts of silicon dioxide, 15-20 parts of calcite, 10-15 parts of forsterite, 8-12 parts of ankerite and 10-14 parts of purple frit.

[0033] Purple frit includes the following raw materials by weight: 50-60 parts of spodumene, 15-20 parts of potassium feldspar, 10-15 parts of bauxite, 10-15 parts of quartz, 3-5 parts of red iron oxide, 2-3 parts of manganese oxide, 3-5 parts of fluorite, and 2-3 parts of sodium carbonate. Adding sugilite to glaze can make the glaze have a unique purple or purple-red color, but due to the high cost of sugilite, it cannot be widely used in industrial production. Therefore, purple frit is used to replace sugilite to provide lithium in ceramic glaze. + 、Al 3+ And purple-red coloring function.

[0034] The green body comprises the following raw materials in parts by weight: 40-50 parts of kaolin, 20-30 parts of quartz, and 15-25 parts of feldspar.

[0035] Specific examples of soda fired gradient fused glaze ceramics are as follows:

[0036] Example 1:

[0037] The glaze comprises the following raw materials in parts by weight: 10 parts of clay, 35 parts of silicon dioxide, 15 parts of calcite, 10 parts of forsterite, 8 parts of ankerite, and 10 parts of purple frit.

[0038] The purple frit includes the following raw materials in parts by weight: 50 parts of spodumene, 15 parts of potassium feldspar, 10 parts of bauxite, 10 parts of quartz, 3 parts of red iron oxide, 2 parts of manganese oxide, 3 parts of fluorite, and 2 parts of sodium carbonate.

[0039] The purple frit includes the following raw materials in parts by weight: 50 parts of spodumene, 15 parts of potassium feldspar, 10 parts of bauxite, 10 parts of quartz, 3 parts of red iron oxide, 2 parts of manganese oxide, 3 parts of fluorite, and 2 parts of sodium carbonate.

[0040] The green body comprises the following raw materials in parts by weight: 40 parts of kaolin, 20 parts of quartz, and 15 parts of feldspar.

[0041] Example 2:

[0042] The glaze comprises the following raw materials in parts by weight: 15 parts of clay, 45 parts of silicon dioxide, 20 parts of calcite, 15 parts of forsterite, 12 parts of ankerite, and 14 parts of purple frit.

[0043] The purple frit includes the following raw materials in parts by weight: 60 parts of spodumene, 20 parts of potassium feldspar, 15 parts of bauxite, 15 parts of quartz, 5 parts of red iron oxide, 3 parts of manganese oxide, 5 parts of fluorite, and 3 parts of sodium carbonate.

[0044] The purple frit includes the following raw materials in parts by weight: 60 parts of spodumene, 20 parts of potassium feldspar, 15 parts of bauxite, 15 parts of quartz, 5 parts of red iron oxide, 3 parts of manganese oxide, 5 parts of fluorite, and 3 parts of sodium carbonate.

[0045] The green body comprises the following raw materials in parts by weight: 50 parts of kaolin, 30 parts of quartz, and 25 parts of feldspar.

[0046] Example 3:

[0047] The glaze comprises the following raw materials in parts by weight: 12 parts of clay, 40 parts of silicon dioxide, 18 parts of calcite, 13 parts of forsterite, 10 parts of ankerite, and 12 parts of purple frit.

[0048] The purple frit includes the following raw materials in parts by weight: 55 parts of spodumene, 18 parts of potassium feldspar, 12 parts of bauxite, 12 parts of quartz, 4 parts of red iron oxide, 2.5 parts of manganese oxide, 4 parts of fluorite, and 2.5 parts of sodium carbonate.

[0049] The purple frit includes the following raw materials in parts by weight: 55 parts of spodumene, 18 parts of potassium feldspar, 12 parts of bauxite, 12 parts of quartz, 4 parts of red iron oxide, 2.5 parts of manganese oxide, 4 parts of fluorite, and 2.5 parts of sodium carbonate.

[0050] The green body comprises the following raw materials in parts by weight: 45 parts of kaolin, 25 parts of quartz, and 20 parts of feldspar.

[0051] The preparation method of soda-fired gradient fused glaze ceramics comprises the following steps:

[0052] Step a, forming a green body and drying it;

[0053] Step b, applying glaze on the body;

[0054] Step c: glaze firing in the kiln, first introduce the carbon salt mixture from one side of the kiln, then switch to introducing the soda mixture from the other side of the kiln;

[0055] Step d: taking the ceramic out of the kiln to obtain the soda-fired gradient fused glaze ceramic.

[0056] In step c, the firing curve is as follows:

[0057] Heating stage 1: from room temperature to 300°C, heating rate 5°C / min;

[0058] Heating stage 2: from 300°C to 800°C, heating rate 8°C / min, maintaining oxidizing atmosphere;

[0059] Heating stage 3: from 800°C to 1150°C, heating rate 3°C / min, maintaining oxidizing atmosphere;

[0060] Insulation stage: total duration 3h;

[0061] Cooling stage 1: from 1150℃ to 800℃, natural cooling, rate ≤10℃ / min;

[0062] Cooling in 2 stages: from 800°C to room temperature, with the door open for air cooling.

[0063] In step c, a first powder spraying port and a first air outlet are provided on one side of the kiln, and a second powder spraying port and a second air outlet are provided on the opposite side;

[0064] The holding phase includes:

[0065] 0-60min: Close the first air outlet, spray carbon salt mixture powder into the kiln from the first powder spraying port, and exhaust from the second air outlet. The glaze surface of the ceramic facing the first powder spraying port is smoked black by the carbon salt mixture powder to form black-brown stripes; spray carbon salt mixture powder from the first powder spraying port at a rate of 3-3.5kg / h, maintain a weak reducing atmosphere, and an O2 content of 1%-3%. In the reducing atmosphere, part of Fe2O3 is converted into Fe3O4, forming a black-brown color. The carbon salt mixture powder is introduced from one side and exhausted from the second air outlet to guide the airflow and powder to flow in one direction, so that the glaze surface on the side facing the first powder spraying port is more receptive to powder than the glaze surface on the other side, so black-brown stripes are formed on the glaze surface on one side.

[0066] 60-120min: First, briefly open the air outlets on both sides to balance the air pressure for 5 minutes, then close the second air outlet, spray soda mixture into the kiln from the second powder spraying port, and exhaust from the first air outlet. The glaze surface of the ceramic facing the second powder spraying port is smoked into red and purple stripes by the soda mixture; briefly open the air outlets on both sides to balance the air pressure to avoid color mixing caused by air flow impact. Spray soda mixture from the second powder spraying port at a rate of 4-4.5kg / h, and the Li in the purple frit + After entering the glaze melt, the Fe 3+ The coordination environment of the sodium + Increase the alkalinity of the glaze melt and stabilize it with Fe 3+ The presence of phosphate and fluorine complexes gives the color a reddish-purple appearance. The intermediate transition zone develops a yellow-brown transitional color due to the atmosphere gradient. The kiln utilizes a unidirectional airflow design, flowing from the powder spray port to the opposite outlet. This ensures independent atmosphere action on both sides. Diffusion creates a concentration gradient in the intermediate zone, avoiding mechanical demarcation. Because the carbon salt and soda mixtures are introduced during high-temperature conditions and for a short duration, they only affect the glaze on the opposite side, resulting in completely different and naturally transitional glazes on both sides and the intermediate zone. When the soda mixture is injected, the airflow flows unidirectionally from the second powder spray port to the first outlet, gradually exposing the opposite side to the oxidizing gas. However, the atmosphere intensity decreases with distance, and combined with the buffering effect of residual reducing carbon particles on the glaze surface, only a weakly oxidizing atmosphere remains on the opposite side.

[0067] 120-180min: Continuous glaze firing, held at heat. Burners are installed on the sidewalls of the kiln. One side of the ceramic is smoked black by the carbon-salt mixture, forming dark brown markings, while the other side is smoked reddish-purple markings by the soda mixture. The transition zone between the two contains both FeO and Fe₂O₃. The forsterite in the top glaze provides the base color, which, combined with the iron ion mixture, creates a yellow-brown color. This yellow-brown color is the result of the combined effect of the base color of the glaze and the carbon-salt and soda mixtures, resulting in a uniform color transition in the middle zone with no mechanical boundaries.

[0068] In step c, the carbon salt mixed powder includes the following raw materials by weight: 50-60 parts of carbon powder, 40-50 parts of wood powder, 7-9 parts of salt powder, and 10-12 parts of red iron oxide powder. The carbon powder and wood powder work together to provide CO gas to reduce Fe 3+ , and the wood-fired texture is formed by the residual carbon particles. Different from the traditional single gas reduction, the salt powder is sodium chloride powder, and a small proportion of salt powder is used as a solvent to accelerate the fusion of carbon powder and the glaze surface.

[0069] In step c, the soda powder mixture includes the following raw materials by weight: 80-90 parts of purple frit powder, 40-50 parts of soda ash, 5-8 parts of fluorite, and 5-8 parts of apatite. + Lower melting point, Al 3+ Stable structure, Li + Synergistic Fe 3+ Purple-red; baking soda quickly releases Na + Strengthen flux, adjust alkaline environment, balance Li + The crystallization tendency of fluorite provides F - Enhanced Fe 3+ Coordination, apatite provides PO4 3- ions, stable red-purple complex ions, through the reasonable proportion of each component, the melting temperature, glaze fluidity, Fe 3+ The coordination and color rendering form the best synergy, ultimately achieving the brightness, uniformity and controllable gradient transition of the purple-red pattern.

[0070] The purple frit powder is prepared as follows: the raw material components of the purple frit are mixed in proportion and ball-milled. After high-temperature melting, the melt is rapidly poured into water and quenched to form glassy fragments. This is then ground into purple frit powder using a ball mill. Using conventional minerals such as spodumene and feldspar to create a ceramic coloring mineral with the same functionality as sugilite significantly reduces production costs while meeting the color requirements of soda-fired gradient glazes.

[0071] The above are only some specific implementation methods of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial changes to the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. Soda fired gradient fused glaze ceramics, characterized by: The invention comprises a body and a glaze. One side of the glaze presents purple-red spots, the other side presents black-brown spots, and the middle transition area presents yellow-brown spots.

2. The soda-fired gradient fused glaze ceramic according to claim 1, characterized in that: The glaze comprises the following raw materials in parts by weight: 10-15 parts of clay, 35-45 parts of silicon dioxide, 15-20 parts of calcite, 10-15 parts of forsterite, 8-12 parts of ankerite, and 10-14 parts of purple frit.

3. The soda-fired gradient fused glaze ceramic according to claim 1, characterized in that: The purple frit comprises the following raw materials in parts by weight: 50-60 parts of spodumene, 15-20 parts of potassium feldspar, 10-15 parts of bauxite, 10-15 parts of quartz, 3-5 parts of red iron oxide, 2-3 parts of manganese oxide, 3-5 parts of fluorite, and 2-3 parts of sodium carbonate.

4. The soda-fired gradient fused glaze ceramic according to claim 1, characterized in that: The green body comprises the following raw materials in parts by weight: 40-50 parts of kaolin, 20-30 parts of quartz, and 15-25 parts of feldspar.

5. The method for preparing soda-fired gradient fused glaze ceramics according to claim 1, characterized in that: The steps include: Step a, forming a green body and drying it; Step b, applying glaze on the body; Step c: glaze firing in the kiln, first introduce the carbon salt mixture from one side of the kiln, then switch to introducing the soda mixture from the other side of the kiln; Step d: taking the ceramic out of the kiln to obtain the soda-fired gradient fused glaze ceramic.

6. The method for preparing soda-fired gradient fused glaze ceramics according to claim 5, characterized in that: In the step c, the firing curve is as follows: Heating stage 1: from room temperature to 300°C, heating rate 5°C / min; Heating stage 2: from 300°C to 800°C, heating rate 8°C / min, maintaining oxidizing atmosphere; Heating stage 3: from 800°C to 1150°C, heating rate 3°C / min, maintaining oxidizing atmosphere; Insulation stage: total duration 3h; Cooling stage 1: from 1150℃ to 800℃, natural cooling, rate ≤10℃ / min; Cooling in 2 stages: from 800°C to room temperature, with the door open for air cooling.

7. The method for preparing soda-fired gradient fused glaze ceramics according to claim 6, characterized in that: In the step c, a first powder spraying port and a first air outlet are provided on one side of the kiln, and a second powder spraying port and a second air outlet are provided on the opposite side; The insulation stage includes: 0-60min: Close the first air outlet, spray the carbon-salt mixed powder into the kiln from the first powder spraying port, and exhaust from the second air outlet. The glaze surface of the ceramic facing the first powder spraying port is smoked black by the carbon-salt mixed powder to form dark brown spots; 60-120min: First, briefly open the air outlets on both sides to balance the air pressure for 5 minutes, then close the second air outlet, spray soda mixture into the kiln from the second powder spraying port, and exhaust from the first air outlet. The glaze surface of the ceramic facing the second powder spraying port will be smoked into reddish-purple stripes by the soda mixture; 120-180min: Keep warm and continue glaze firing.

8. The method for preparing soda-fired gradient fused glaze ceramics according to claim 7, characterized in that: In step c, the carbon-salt mixed powder comprises the following raw materials in parts by weight: 50-60 parts of carbon powder, 40-50 parts of wood powder, 7-9 parts of salt powder, and 10-12 parts of red iron oxide powder.

9. The method for preparing soda-fired gradient fused glaze ceramics according to claim 7, characterized in that: In step c, the soda powder mixture comprises the following raw materials in parts by weight: 80-90 parts of purple frit powder, 40-50 parts of soda ash, 5-8 parts of fluorite, and 5-8 parts of apatite.

10. The method for preparing soda-fired gradient fused glaze ceramics according to claim 9, characterized in that: The preparation method of the purple frit powder is as follows: various raw material components of the purple frit are mixed in proportion and ball-milled; after high-temperature melting, the melt is quickly poured into water and quenched to form glassy fragments, which are then ground into purple frit powder in a ball mill.