9 display bone China defects

( 2) Avoid and layer thickness, because bone porcelain glaze layer too thick, will weaken and flexibility, at the same time in the process of cooling due to bone porcelain glaze layer heat balance is difficult to establish stress, so the bone porcelain glaze layer thick easy to crack. But should take into consideration the color shade is appropriate, in the case of not affect glaze colors, with slightly BoWeiJia. ( 3) Strictly control the bone porcelain glaze slurry fineness, bone porcelain glaze grinding have to carefully adsorption water more, dry easy to crack. If when firing glaze viscosity forming roll glaze, even at a less material viscosity, its dehiscence can still be found faint trace. But bone porcelain glaze thick or not after grinding, which contains the coarser quartz grain, in the process of burning heating and cooling, glaze cracks caused by the crystal transformation. Glaze glaze slurry fineness should regard bone porcelain variety, dug the hole screen more than 0. 03 - 0. 1% is preferred. ( 4) Strictly control the bone porcelain sintering temperature and prolong the preservation time, attention, sintering temperature can't is too high, otherwise the bone porcelain glaze in the case of burnt is easy to crack. ( Refer to chapter 3 & other; Crack & throughout; ) 2, bone porcelain glaze smoking meaning: dark surface of bone China products, with a layer of smoke, also known as smoke, also called eat smoke. Partial or all of the color yellow, dark gray, brown and green green, belongs to smoke, produced in ingredients and firing. The reason: 1) The main reasons that smoke, ceramic billet is organic oxidation is not in the body. With a down-draft kiln firing, it is due to the too thickness of coal seam combustion chamber, high temperature, poor ventilation, CO is thicker, because CO can seize the bone porcelain body oxygen into CO2 volatile, as to make the bone porcelain body cannot oxidation of carbon, called black smoke. ( 2) If the tunnel kiln firing, because the flue gas flow back and the firing kiln oxidizing atmosphere, decomposition, not smoking also can produce. In the process of firing, due to fuel ceramic billet volume caused by unburned carbon. Carbon in 100 & ndash; 700 ℃ temperature range between invasive bone porcelain glaze billet, at this time if not oxidizing flame burning the carbon oxidation to carbon dioxide discharge, will continue to rise in temperature of carbon are covered with glaze layer after melting, can't eduction, local cooling after bone porcelain products become black. ( 3) Too much of the limestone content in bone porcelain glaze, easy cause smoking. To overcome the way: ( 1) Bone China strict control of burning process, coal oxidation period, burn notice of black smoke, the carbon oxidation fully eliminate y reduction not too early or too late to prevent coaling too urgent. Oil nozzle tunnel kiln burning wind oil ratio to be appropriate. Adjusting the damper height and increase the chimney smoke, the pressure in the kiln to maintain bone system stability, prevent the backflow of flue gas temperature is controlled properly speed should not be heating up too fast, to prevent oxidation. When bone porcelain glaze began to melt, should use neutral flame combustion, containing organic more bone porcelain body should have enough oxidation time, cannot too be reducing flame fuel sulfur compounds should be low, at the same time to make the sulfur gases don't stay too long in the stove. ( 2) Use less by feldspathic glaze, limestone, grasp the bone porcelain glaze melting temperature. ( Refer to the chapter smoke & throughout; ) 。 — Bone China hotel bowl of plates to be continued. 。 。 。 。 。