12 display bone China defects

( 4) Burning method is wrong, vitrified start period, if the temperature rise abruptly, can make the bone porcelain bo changes too fast, so closed, carbon is not easy to discharge to promote high temperature foaming. Stages of the fire, bone kilns to reduce the temperature for some reasons and sudden increase ( Such as electricity) So often form bone porcelain glaze bubble. Glaze firing iron points than other bone porcelain glaze easier to form bubbles. Such as: fe203-2 - - - - - - 4 fe0 + 02 a balance type changes extremely easily, which makes it to the atmosphere and the temperature is very sensitive, if in the high temperature of 1300 ℃ and the presence of a reducing agent, very easy to promote Fe203 for thermal decomposition of the balance in the move to the right. If Fe203 too late during the reduction period all decomposition, decomposition at high temperature was to continue, there is a bubble because of decomposed big elastic general celadon with lime as flux for many years, when burnt, calcium carbonate decomposition gas sometimes too late to escape from the bone porcelain glaze, and should continue to burn when zi chan raw liquid will continue to discharge, creates many bubbles is any bone porcelain glaze microstructure are nothing more than is commonly, air bubble, and crystal glass. With strong reducing flame burning bone China products, due to the large amounts of carbon deposition are more likely to form bubbles. To overcome the way: ( 1) Raw material, eliminate impurities, adjust the bone porcelain glaze formula, try to avoid do glaze with high sulfur content of raw materials. Expanding the scope of the bone porcelain glaze firing, make it has a high melting point ( Good bone porcelain glaze began melting temperature just below the final calcining temperature 40 ℃ or so) And low viscosity. Using breaking grinding, fine grinding refractory oxide, make refractory raw materials particles more thin, increase the degree of dispersion. ( 2) Try to use water less when the fettling, even hot water with water only. Pay attention to the dry method, found that the bone porcelain body surface alkali skin with fine sand paper to grind. ( 3) Decrease the seting density, relative to improve firing conditions increase product calcined oxidation time. Extension of the 800 - 1100 c, firing time, and there is enough heat preservation time, make the bone porcelain glaze and bone porcelain body can be fully oxidation carbon and other organic matter in free. Using coal to do net stoking the fire burning, well ventilated, 900 - Strong reducing flame burning (1200 c period The concentration of C0 had enough) The raw material of iron special child to stage heating up smoothly, the fire can not soar plunging. If use tunnel kiln firing, can appropriate increase in the temperature of the tropical, make its full oxidation. ( 4) Adopt low sulphur content of fuel, such as heavy oil, sulfur content below 0, 5 % and accurately adjust burning nozzle. As far as possible avoid the use of high sulphur content of raw material do glaze. 7, bone porcelain glaze deficiency meaning: glaze bone China products, bone porcelain glaze on both sides of the partial to roll and middle fetal bone is called shrinkage glaze. Some bone porcelain glaze layer spalling occurs, if in the porcelain body with high K20, Na20 content and ceramic glaze glaze layer thick, can appear after firing glaze most peeling phenomenon from the body, and is common in the practical work of local rolled glaze glaze is also called off. Roll in the part of the glaze is associated with artifacts shape, mostly in the groove edge parts of the product or concave and convex part of the sculpture porcelain. Belongs to bone porcelain glaze, produced in the bone porcelain glaze, ceramic glazing and burning process. The reason: 1) Bone and bone porcelain glaze porcelain blank does not adapt, namely bone porcelain glaze ( Or bone porcelain blank) Bad ingredients, the room temperature or in the glaze melt glue layer locally or from the body. Such as biscuit firing glaze billet, used to not plain burned bone porcelain body, is prone to bone porcelain glaze. This is because the bone and bone porcelain glaze porcelain blank dry, differential shrinkage caused by high temperature viscosity of glaze is also easy to produce this kind of defect & ndash; Bone China gift of furnishing articles to be continued. 。 。 。 。 。