How is the glaze of ceramics mixed?
There are many kinds of glazes in ceramics, and the following types are described as follows:1 lead glaze and lead-free glazeIn the lead glaze formulation of building ceramics and sanitary ceramics products in use, from the source of lead metasilicate lead or lead borosilicate frit. Lead metasilicate typical formula in practical production consists of: 1 0.10 three Sergei lead, two aluminum oxide, 1.89 silica, the weight ratio of 64%: 3% lead oxide, alumina, silica, 33%). The glaze gives minimum solubility. If the increase of the content of alkaline oxide and boron oxide, can lead to increased frit solubility of lead. In countries such as Holland and lead-free solubility limit, they use low melting or high dissolved silicate lead and lead borate frit glaze. The difference between lead glaze and lead-free glaze involves the quality of the product. However, at higher than 1150 DEG C, the lead is obviously volatilized, while the temperature limit is higher than this, and the lead glaze is no longer used. Lead free glaze is a kind of weight with a lead content of less than 1%. With the increasingly stringent environmental requirements, the ceramic industry has gradually shifted all the use of lead-free glaze lead-free flux and lead-free pigment.Strontium glaze has good effect in replacing lead glaze. In addition to its wide firing range, low firing temperature and the formation of gloss glaze surface, it also has good wear resistance. It becomes a kind of lead-free glaze glaze is very good, and when it is under glaze color agent when used together, almost can not see the adverse effects on the pigment, but in common with the chrome tin red glaze, must be added within a certain calcium oxide, to stabilize the tone quality.
2, raw glaze and glazeBecause the ceramic raw glaze composition does not use frit, so they only use the highest sintering temperature greater than 1150 DEG C. Usually available to do the production of hard porcelain, stoneware, porcelain, glass sanitary porcelain and all kinds of low expansion body glaze. Raw glaze contains mineral solvents, such as feldspar or nepheline syenite, plus clay, quartz, dolomite, calcium carbonate, zirconium silicate as raw materials and Zinc Oxide. Low expansion raw glaze also uses lithium feldspar as flux. Raw glaze will not have any form of glass phase in firing must be sufficient time to vent gas from the raw material work, glaze, glaze melt can obtain smooth and no bubbles so long time than fritted glaze raw glaze firing. The firing temperature is lower than 1150 DEG C, it should adopt the frit glaze. In addition to the use of low-temperature fast firing process, need to increase the content of frit glaze.3, once firing glaze and two firing glazeFor ceramic enterprises, the glaze products are fired at a time, which saves energy and economy more than the two times, greatly reduces the cost of products and is conducive to environmental protection. Single firing is very beneficial to products of high added value, such as bulky sanitary ware or large insulators. But the main advantage of the two firing is that we can select and eliminate some defective semi-finished products, and also produce products of high quality and low cost. In the first firing process, the glaze and the body are mature at the same time, and the formation of the intermediate layer of the glaze and the glaze can often increase the strength of the product, and the complete vitrification of the body is also obvious. In the firing process, the glaze often contains binder, which can control the evaporation rate of water from the glaze and control the movement of water into the porous billet. The glaze binder plays a role in increasing the hardness of the drying glaze.
