High-shading low-contrast reddish brown colored drawing porcelain glaze and preparation method thereof

Abstract

The invention discloses a high-shading low-contrast reddish brown colored drawing porcelain glaze and a preparation method thereof, and belongs to the technical field of inorganic non-metallic materials. The porcelain glaze is prepared from the following components in percentage by mass: 18 to 25 percent of quartz, 25 to 40 percent of feldspar, 4 to 6 percent of calcite, 10 to 20 percent of kaolin, 8 to 12 percent of iron-rich clay, 0.3 to 0.8 percent of sodium carboxymethyl cellulose and 0.1 to 0.3 percent of sodium tripolyphosphate. The preparation method comprises the following steps: carrying out wet ball milling on a glaze raw material to prepare glaze slip, and controlling the specific gravity to be 1.40-1.50 g / cm < 3 >; applying to a glaze blank to form a glaze layer with the thickness of 0.2-0.5 mm; and sintering by keeping the temperature of 1150-1190 DEG C in an oxidizing atmosphere for 40-60 minutes. Through specific component design and application of the non-presintered iron-rich clay, in combination with optimized glaze slip performance and firing system, directional diffusion of iron ions and precipitation of alphaFe2O3 microcrystals are effectively promoted, and a reddish brown colored drawing effect with natural color transition, strong rendering feeling and low contrast is obtained; the technical problem that traditional reddish brown colored drawing is fuzzy in boundary and uncontrollable in shading is solved, and the product is high in artistic expressive force and good in process repeatability.

Description

Technical Field

[0001] This invention relates to the field of inorganic non-metallic materials technology, specifically to a high-smudge, low-contrast reddish-brown painted porcelain glaze and its preparation method. Background Technology

[0002] Reddish-brown painted porcelain, an important category of traditional Chinese iron-based underglaze porcelain, holds unique value in the fields of art ceramics and antique-style porcelain due to its warm and rustic hues. This technique uses natural iron-rich minerals (such as mottled stone and purple clay) as the main coloring material, fired in an oxidizing atmosphere. This causes iron elements in the glaze to precipitate in the form of α-Fe2O3 (hematite) microcrystals, creating a typical reddish-brown decorative effect. Compared to white-ground black-decorated porcelain colored with Fe3O4 under a reducing atmosphere, reddish-brown glaze possesses a softer and more elegant artistic quality in its color expression.

[0003] However, in actual firing processes, existing technologies often suffer from "bleeding" problems such as blurred color boundaries and uneven coloring due to insufficient control over iron ion migration, severely affecting the clarity of the pattern and the consistency of the decorative effect. This not only restricts the development of red-brown painted porcelain in the field of high-end art porcelain but also poses a serious challenge to its industrial application. Therefore, how to achieve controllable adjustment of the bleeding effect while maintaining the unique artistic charm of red-brown enamel has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a high-bleeding, low-contrast reddish-brown painted porcelain glaze and its preparation method. By promoting the migration and diffusion of iron ions during firing while avoiding excessive flow, a reddish-brown porcelain glaze with soft color transitions, strong rendering effect, and low contrast is obtained.

[0005] This invention is achieved through the following technical solution: A high-bleeding, low-contrast reddish-brown painted porcelain glaze, comprising the following components by weight percentage: Quartz: 18%–25%; Feldspar: 25%–40%; Calcite: 4%–6%; Kaolin: 10%–20%; Iron-rich clay: 8%–12%; Sodium carboxymethyl cellulose: 0.3%–0.8%; Sodium tripolyphosphate: 0.1%–0.3%.

[0006] Preferably, the iron-rich clay is unburnt iron-rich clay with an Fe2O3 content of 5% to 8%.

[0007] Preferably, the quartz is at least one of natural quartz and synthetic quartz; the feldspar is at least one of potassium feldspar, sodium feldspar, and calcium feldspar.

[0008] A method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze includes the following steps: Step 1: Weigh the glaze raw materials according to the ratio, and use wet ball milling to obtain a reddish-brown painted glaze slurry, controlling the specific gravity of the glaze slurry to be 1.40~1.50 g / cm³; Step 2: Apply the painted glaze paste to the glazed body to form a glaze layer, and let it dry; Step 3: Hold the glazed porcelain body at 1150-1190℃ in an oxidizing atmosphere for 40-60 minutes, then let it cool naturally to obtain a high-smearing, low-contrast reddish-brown painted porcelain glaze.

[0009] Preferably, the process parameters for wet ball milling in step 2 are as follows: Raw materials: The mass ratio of grinding stone to water is 1:1.4:1.0; the grinding speed is 250-280 r / min; the grinding time is 40-45 min.

[0010] Preferably, the glazing method is spraying or brushing.

[0011] Preferably, in step 3, the firing heating rate is 3-5°C / min.

[0012] Preferably, the thickness of the glaze layer is 0.2 to 0.5 mm.

[0013] A type of porcelain, comprising a glazed body and a highly diffused, low-contrast reddish-brown painted porcelain glaze adhered thereto.

[0014] Preferably, the glaze blank comprises, by mass percentage, 35%~40% kaolin, 25%~30% feldspar, 15%~20% quartz and 10%~20% porcelain stone.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: This application provides a high-blurring, low-contrast reddish-brown painted porcelain glaze. The calcite content is a crucial technical step in producing this glaze. Controlling the calcite content and reducing the calcium content prevents the formation of anorthite. This ensures the pigment particles are not completely encapsulated, resulting in a high degree of diffusion. The glaze uses 18%–25% quartz as a framework to ensure high-temperature stability, and 25%–40% feldspar and 4%–6% calcite as a composite fluxing system. This ensures complete melting while effectively inhibiting excessive anorthite formation, thus avoiding excessive vitrification of the glaze surface and its hindrance to iron ion diffusion. Crucially, 8%–12% unfired iron-rich clay is used as the coloring source. Its active iron components, water of crystallization, and organic matter decompose and release gases during firing, forming microscopic channels for Fe... 3+The migration of ions provides the driving force and pathway, which, combined with the thickening and water-retaining effects of 0.3%~0.8% sodium carboxymethyl cellulose and the dispersing and stabilizing functions of 0.1%~0.3% sodium tripolyphosphate, collectively promotes the formation of a reddish-brown halo effect with natural color transitions, soft edges, and artistic rendering in the oxidizing atmosphere at 1150~1190℃. This composition design not only breaks through the technical bias of traditional reddish-brown painting that pursues clear boundaries, but also achieves controllable blending degree and contrast under the conditions of simple composition and strong process compatibility, possessing good industrial applicability and artistic expression. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is an optical microscope image of a cross-section of a porcelain shard with a high-smudged, low-contrast reddish-brown painted porcelain glaze according to the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0020] A high-smudge, low-contrast reddish-brown painted porcelain glaze, comprising, by weight percentage: 18%–25% quartz, 25%–40% feldspar, 4%–6% calcite, 10%–20% kaolin, 8%–12% iron-rich clay, 0.3%–0.8% sodium carboxymethyl cellulose and 0.1%–0.3% sodium tripolyphosphate.

[0021] The quartz is at least one of natural quartz and synthetic quartz, and is the main skeleton component of the glaze, providing good high-temperature resistance and chemical stability.

[0022] The feldspar is at least one of potassium feldspar, sodium feldspar, and calcium feldspar, and plays a role in fluxing and lowering the melting temperature in the glaze.

[0023] Calcite is an important flux in glazes, which can lower the melting temperature of glazes and promote the formation of glaze layers.

[0024] Kaolin is one of the key components in glazes, possessing good plasticity and binding properties, which can enhance the adhesion and formability of glazes.

[0025] The pre-fired iron-rich clay is the main colorant for underglaze painting decoration. It is made from natural iron-rich clay through pre-firing at 700~900℃, which converts the iron element into stable α-Fe2O3, resulting in bright reddish-brown patterns. Its Fe2O3 content is controlled at 5%~8%.

[0026] The sodium carboxymethyl cellulose (CMC-Na) has good thickening, water retention and binding properties, which can improve the stability of the glaze slurry and the smoothness of the finished glaze surface.

[0027] The sodium tripolyphosphate, as a dispersant, helps improve the fluidity and stability of the glaze and strengthens the bond between the glaze and the body.

[0028] Correspondingly, this application also provides a type of porcelain, comprising a white glazed body and a reddish-brown painted glaze layer attached to its surface.

[0029] The glaze blank comprises, by weight percentage, 35%–40% kaolin, 25%–30% feldspar, 15%–20% quartz, and 10%–20% porcelain stone.

[0030] The reddish-brown painted glaze layer comprises, by weight percentage: 18%–25% quartz, 25%–40% feldspar, 4%–6% calcite, 10%–20% kaolin, 8%–12% iron-rich clay, 0.3%–0.8% sodium carboxymethyl cellulose, and 0.1%–0.3% sodium tripolyphosphate.

[0031] Correspondingly, this application also provides a method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze, comprising the following steps: Step 1: Prepare the glaze blank. The clay body is made by crushing the raw materials (35%~40% kaolin, 25%~30% feldspar, 15%~20% quartz and 10%~20% porcelain stone); the clay body is then repeatedly pounded by hand to remove excess gas, shaped, and dried to obtain the body; a transparent glaze is applied to make a glazed body, which is then left to stand for later use.

[0032] Step 2: Prepare the glaze for painting: Weigh out unfired iron-rich clay and other glaze raw materials (quartz, feldspar, calcite, kaolin, sodium carboxymethyl cellulose and sodium tripolyphosphate) according to the specified ratio, and prepare a reddish-brown painted glaze slurry by wet ball milling. During the ball milling process, the ratio of raw materials: milling stone: water is 1:1.4:1.0, the ball milling speed is 250~280 r / min, the time is 40~45 min, and the specific gravity of the glaze slurry is controlled to be 1.40-1.50 g / cm³.

[0033] Step 3, Apply color: The reddish-brown glaze obtained in step 2 is applied to the glaze blank prepared in step 1 by spraying or brushing to form an uneven glaze layer with a thickness of 0.2-0.5 mm. After drying, the glaze blank is obtained.

[0034] Step 4, firing: The colored blank obtained in step 3 is fired at 1150-1190℃ in an oxidizing atmosphere for 40-60 minutes. After natural cooling, the high-smudged, low-contrast reddish-brown painted porcelain glaze is obtained.

[0035] Example 1 A method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze includes the following steps: Step 1: The raw materials for the body are crushed to obtain body clay; by mass percentage, the body clay includes: 38% kaolin, 28% feldspar, 18% quartz and 16% porcelain stone. The raw materials for the body clay are repeatedly pounded by hand to remove excess gas, shaped, and dried to obtain the body; after applying a transparent glaze, it is made into a glazed body and left to stand for later use.

[0036] Step 2: The raw materials are pulverized and ball-milled to obtain a reddish-brown painted glaze slurry. The glaze raw materials, by mass percentage, include 22% quartz, 32% feldspar, 4% calcite, 16% kaolin, 10% unfired iron-rich clay (Fe2O3 content 6.5%), 0.5% sodium carboxymethyl cellulose, and 0.2% sodium tripolyphosphate. The glaze slurry is wet-milled. During wet-milling, the ratio of glaze raw materials:milling stone:water is 1:1.5:1.0, the milling speed is 260 r / min, the milling time is 35 min, and the specific gravity of the glaze slurry is controlled at 1.45 g / cm³.

[0037] Step 3: Apply the obtained reddish-brown painted glaze paste to the glazed body using the spray glazing method, controlling the glaze layer thickness to be 0.3mm, and let it dry to obtain the painted body; Step 4: Place the colored porcelain blank into an electric kiln and heat it to 1170°C at a heating rate of 4°C / min. Hold it at this temperature for 50 minutes in an oxidizing atmosphere, and then let it cool naturally to room temperature to obtain a high-blurring, low-contrast reddish-brown painted porcelain glaze.

[0038] Example 2 A method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze includes the following steps: Step 1: The raw materials for the body are crushed to obtain body clay; by mass percentage, the body clay includes: 36% kaolin, 30% feldspar, 17% quartz and 17% porcelain stone. The raw materials for the body clay are repeatedly pounded by hand to remove excess gas, shaped, and dried to obtain the body; after applying a transparent glaze, it is made into a glazed body and left to stand for later use.

[0039] Step 2: The raw materials are pulverized and ball-milled to obtain a reddish-brown painted glaze slurry. The glaze raw materials, by mass percentage, include 20% quartz, 35% feldspar, 6% calcite, 18% kaolin, 12% unfired iron-rich clay (Fe2O3 content 7.2%), 0.6% sodium carboxymethyl cellulose, and 0.3% sodium tripolyphosphate. The glaze slurry is wet-milled. During wet-milling, the ratio of glaze raw materials:milling stone:water is 1:1.5:1.0, the milling speed is 270 r / min, the milling time is 40 min, and the specific gravity of the glaze slurry is controlled at 1.42 g / cm³.

[0040] Step 3: Apply the obtained reddish-brown painted glaze paste to the glazed body using the brushing method to form an uneven glaze layer with a thickness of 0.2-0.5mm. Let it dry to obtain the painted body. Step 4: Place the painted porcelain blank into an electric kiln and heat it to 1160°C at a heating rate of 5°C / min. Hold it at this temperature for 55 minutes in an oxidizing atmosphere, and then let it cool naturally to room temperature to obtain a high-blurring, low-contrast reddish-brown painted porcelain glaze.

[0041] Example 3 A method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze includes the following steps: Step 1: The raw materials for the body are crushed to obtain clay. By mass percentage, the clay consists of 40% kaolin, 25% feldspar, 20% quartz, and 15% porcelain stone. The raw clay is repeatedly pounded by hand to remove excess gas, shaped, and dried to obtain the body. After applying a transparent glaze, it is made into a glazed body and left to stand for later use.

[0042] Step 2: The raw materials are pulverized and ball-milled to obtain a reddish-brown painted glaze slurry. The glaze raw materials, by mass percentage, include 25% quartz, 25% feldspar, 5% calcite, 15% kaolin, 8% unfired iron-rich clay (Fe2O3 content 5.8%), 0.8% sodium carboxymethyl cellulose, and 0.1% sodium tripolyphosphate. The glaze slurry is wet-milled. During wet-milling, the ratio of glaze raw materials:milling stone:water is 1:1.5:1.0, the milling speed is 250 r / min, the milling time is 30 min, and the specific gravity of the glaze slurry is controlled at 1.48 g / cm³.

[0043] Step 3: Apply the obtained reddish-brown painted glaze paste to the glazed body using the spray glazing method, controlling the glaze layer thickness to be 0.4mm, and let it dry to obtain the painted body; Step 4: Place the painted porcelain blank into an electric kiln and heat it to 1180°C at a heating rate of 3°C / min. Hold it at this temperature for 45 minutes in an oxidizing atmosphere, and then let it cool naturally to room temperature to obtain a high-blurring, low-contrast reddish-brown painted porcelain glaze.

[0044] Example 4 A method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze includes the following steps: Step 1: Prepare the glaze blank. Same as Example 1.

[0045] Step 2: Prepare the glaze for painting: Quartz: 18%, Feldspar: 25%, Calcite: 4%, Kaolin: 20%, Unburned Iron-Rich Clay (Fe2O3 content 5.0%): 8%, Sodium Carboxymethyl Cellulose: 0.3%, Sodium Tripolyphosphate: 0.1% Wet ball milling, raw material: milling stone: water = 1:1.4:1.0, rotation speed 250 r / min, time 45 min, glaze slurry specific gravity controlled at 1.40 g / cm³.

[0046] Step 3, Apply color: The glaze is applied by brushing, with the glaze thickness controlled at 0.2 mm, and then allowed to dry.

[0047] Step 4, firing: The temperature was increased to 1150℃ at a rate of 4℃ / min, held at that temperature for 60 minutes in an oxidizing atmosphere, and then allowed to cool naturally.

[0048] Example 5 A method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze includes the following steps: Step 1: Prepare the glaze blank. Same as Example 1.

[0049] Step 2: Prepare the glaze for painting: The glaze raw materials, by weight percentage, include: quartz: 25%, feldspar: 40%, calcite: 6%, kaolin: 10%, unfired iron-rich clay (Fe2O3 content 8.0%): 12%, sodium carboxymethyl cellulose: 0.8%, and sodium tripolyphosphate: 0.3%. Wet ball milling: raw material: milling stone: water = 1:1.4:1.0, rotation speed 280 r / min, time 40 min, glaze slurry specific gravity controlled at 1.50 g / cm³.

[0050] Step 3, Apply color: The glaze is sprayed to control the glaze thickness to 0.5 mm and then dried.

[0051] Step 4, firing: The temperature was increased to 1190℃ at a rate of 5℃ / min, held at that temperature for 40 minutes in an oxidizing atmosphere, and then allowed to cool naturally.

[0052] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

[0053] See Figure 1 As can be seen from the image, the microstructure mainly consists of two parts: the surface of the glaze layer, where a few tiny bubbles are visible; and the lower, lighter-colored area, which is the main body of the glaze layer, containing numerous bubbles of varying sizes, along with a slight brownish tint formed by the diffusion of coloring elements such as iron ions. These bubbles are formed when gases from the body / glaze were not completely expelled during the ceramic firing process and are encased in the glaze layer. The bubbles are uneven in size and naturally distributed, with some bubbles showing oxidation tint at their edges. The brown tint in the image is a microscopic manifestation of the "high tint, low contrast" glaze. The coloring elements (iron) in the glaze diffuse at high temperatures, creating a soft color transition, weakening the boundary contrast within the glaze layer, and ultimately presenting a hazy visual effect. This glaze style can conceal minor unevenness during the glazing process, improving the product qualification rate.

[0054] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A high-smudge, low-contrast reddish-brown painted porcelain glaze, characterized in that, By mass percentage, it includes the following components: Quartz: 18%–25%; Feldspar: 25%–40%; Calcite: 4%–6%; Kaolin: 10%–20%; Iron-rich clay: 8%–12%; Sodium carboxymethyl cellulose: 0.3%–0.8%; Sodium tripolyphosphate: 0.1%–0.3%.

2. The high-bleeding, low-contrast reddish-brown painted porcelain glaze according to claim 1, characterized in that, The iron-rich clay is unburnt iron-rich clay with an Fe2O3 content of 5% to 8%.

3. A high-bleeding, low-contrast reddish-brown painted porcelain glaze according to claim 1 or 2, characterized in that, The quartz is at least one of natural quartz and synthetic quartz; the feldspar is at least one of potassium feldspar, sodium feldspar, and calcium feldspar.

4. A method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze, characterized in that, Includes the following steps: Step 1: Weigh the glaze raw materials according to the ratio, and use wet ball milling to obtain a reddish-brown painted glaze slurry, controlling the specific gravity of the glaze slurry to be 1.40~1.50 g / cm³; Step 2: Apply the painted glaze paste to the glazed body to form a glaze layer, and let it dry; Step 3: Hold the glazed porcelain body at 1150-1190℃ in an oxidizing atmosphere for 40-60 minutes, then let it cool naturally to obtain a high-smearing, low-contrast reddish-brown painted porcelain glaze.

5. The method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze according to claim 4, characterized in that, The process parameters for wet ball milling in step 2 are as follows: Raw materials: The mass ratio of grinding stone to water is 1:1.4:1.0; the grinding speed is 250-280 r / min; the grinding time is 40-45 min.

6. The method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze according to claim 4, characterized in that, The glazing method is either spraying or brushing.

7. The method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze according to claim 4, characterized in that, In step 3, the firing heating rate is 3-5℃ / min.

8. The method for preparing a high-smudged, low-contrast reddish-brown painted porcelain glaze according to claim 4, characterized in that, The thickness of the glaze layer is 0.2 to 0.5 mm.

9. A type of porcelain, characterized in that, Includes a glazed body, and the high-smudged, low-contrast reddish-brown painted porcelain glaze of any one of claims 1-3 adhering to its surface.

10. A type of porcelain according to claim 9, characterized in that, The glaze blank comprises, by weight percentage, 35%–40% kaolin, 25%–30% feldspar, 15%–20% quartz, and 10%–20% porcelain stone.

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