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stonware color glazed mug/solid color mug cup Ceramic glaze
|Ceramic Mug From:Xinxiang Ceramic Mug Manufacturers |
|stonware color glazed mug/solid color mug cup|
(1) "glaze" the meaning of the composition and structure
"Glaze" means coated on the surface of the ceramic body a thin layer of glassy material, its thickness is usually 0.2 - 0.8mm.
Glaze layer can improve the surface properties of the ceramic body, such as reducing the surface porosity, the surface becomes smooth and increase the mechanical strength of the products and improve chemical resistance surface, while beautifying the appearance of the product. Usually require glaze can accommodate different types of body, and can mature at different temperatures, and can exhibit a variety of special properties.
Silicate composition similar to the glaze glass. This special glass is considered to be composed of a particulate structure formed, arranged in the form of non-geometric, short-range order, the remote disordered structure. When this layer of glass material is cooled into a solid, retained the nature of the liquid, but it is not an independent existence, but attached to the surface of the ceramic body, in the firing process it will not be as free-flowing as glass. Oxides can form part of the glass, such as Si02, B2O3, P2O5, As2O3 and GeO2. Silicon and boron oxides in the ceramic glaze, commonly used as glass forming agent, i.e., a network former. High melting point of silicon oxide, usually by the addition of K20, Na2O, CaO, MgO and other substances and the melting point is lowered, and change its other properties. K2O, Na2O, CaO, MgO, etc., they can not form a network, but can affect the nature of a series of networks, it is known as a network modifier. In addition, the formation process of the glass may also be added to control the stability of Al2O3, it is sometimes considered as a network former.
Glaze structure "continuous disordered structure." This disordered structure without interference from the grain boundary and grain boundaries.
(2) the representation of the glaze composition
Glaze composition used in three ways to indicate that the percentage of the raw material quality representation, consisting of the percentage of chemical notation and empirical formula notation (ie Seigel said glaze formula or formula). Using enamel glaze style than using chemical composition of glaze recipes and more directly reflect the composition and nature of the glaze. It can be more easily compare the different glaze, and can be used to predict the properties of the glaze.
The relevant number of different glaze oxide row together, and according to their role in the glaze will be divided into three groups oxide. The first group comprises more alkali oxides and alkaline earth metal oxides, their use as soft or hard flux presence of flux, such as K2O, Na2O, CaO and Mg0 and the like; the second group is a neutral oxide R203 (or called amphoteric oxide was mainly Al2O3); the third group is an acidic oxide RO2 (mainly SiO2).
The use of the method for grouping the oxide, we can confirm that the first group of substances can change the network structure of glass glaze; a second group of amphoteric oxides, depending on the contents, it can change the network structure, or may be formed as a network oxide; the third group was formed an oxide network. Seigel glaze formula between the molar ratios of oxides, in order to facilitate the comparison of different glaze artificially provides the first set and the number of moles of oxides as a reference, so that it is 1, so that other oxides the number of moles can be determined.
Such as: 1 (R2O + RO) mR2O3 nRO2, usually written (R2O + RO) mR2O3 nRO2.
A glaze glaze formula can be easily calculated from the chemical composition of the glaze. Number of moles of alkali oxides is more concise and more. Other oxides can press the reference number of moles of alkaline oxides obtained by calculation.
(3) Calculate the glaze recipe from the glaze formula
One kind of glaze glaze formula is as follows: (0.3K2O + 0.7CaO) 0.5 Al2O3 4SO2
We based it can be calculated by inverse method formula, the choice of materials must be able to meet a variety of oxide glaze formulas, such as feldspar, calcite, clay and quartz, and must provide accurate chemical composition of these materials used glaze.
Its molar composition ratio between the feedstock can check out, according to various compositions and their proportions, calculated mass (corresponding to the number of moles of the formula X amount of starting material) starting material:
Feldspar: 0.3 mo1X556.78 g / mot = 167.01 g
Clay: 0.2 mol X 25.1 g / mol = 51.64 g
Quartz: 1.8 mol X 60.1 g / mot = 108.16 g
Calcite: 0.7 mol X100.1 g / mot = 70.05g
Total: 396.87 g
Glaze recipes can quickly calculate the amount based on the total amount (396.87 g) and a variety of raw materials, as follows (percentage by mass):
So the glaze recipe for (mass percentage): Feldspar: 42.1%, clay: 13.0%, quartz: 27.2%, calcite: 17.7% Total: 100%
Classification can be classified in the following manner:
Press glazing body is different, can be divided into: ceramic glaze, fine pottery glaze, stoneware glaze, enamel, etc;
glaze different preparation methods can be divided into: raw glaze, some frit, glaze frit and salt;
by major or important glaze materials can be divided into: lead glaze, boron glaze, feldspar glaze, dolomite glaze, Ming glaze, glaze wrong, tin glaze;
Press glaze firing temperature (mature temperature) level can be divided into: low temperature glaze, enamel and high temperature glazes;
Press the microstructure and optical properties characteristic of the glaze can be divided; transparent glaze, opaque glaze, crystalline glaze, matte glaze, semi-gloss and gloss enamel glaze.
Another classification is in accordance to play a major role in boosting the oxide glaze points, such as calcium glaze, glaze magnesium, zinc glaze.
Lead oxide is a major conventional flux. As a strong flux, lead glaze having a high gloss, the nature of high thermal expansion coefficient, low viscosity, low surface tension and a wide melting temperature range. Lead oxide glaze for most opaque coloring and can play a catalytic role. Transparent lead glaze tends to exhibit a yellowish hue. Lead oxide has been limited use of toxicity for the effective control of lead leaching, must be controlled (R2O + RO + Al2O3) / Si02: the molar ratio to the maximum value of less than 0.50 if the ratio is greater than or equal to 0.5, you should increase the Cr203 and the content of B2O3 and join TiO2, BaO, ZnO, SnO2 and ZrO2 to reduce lead dissolution. To reduce the toxicity of lead, lead oxide prepared in advance will often lead silicate frit before use.
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