Bone porcelain firing with polished 6

From the bubble growth factor analysis is as follows (1) bone porcelain glaze composition, especially the carbonate, alkali metal can increase the viscosity (2) the bone porcelain glaze viscosity (3) (4) the surface tension of the bone porcelain glaze bone porcelain glaze layer thickness (5) the kiln atmosphere big bubble defects commonly called & other; Blisters & throughout; , vesicles called & other; Brown eyes throughout the &; &ldquo仍然; Pinhole & throughout; &ldquo仍然; Pig pores & throughout; , patches are called & other Orange glaze & throughout; &ldquo仍然; Pear flesh & throughout; And so on. “ Blisters & throughout; Is generally larger bubbles, floating on the surface of bone porcelain glaze layer, destruction of bone porcelain glaze layer surface smoothness, if after the bubble burst, don't have enough time to trim or flow flat, bone porcelain glaze is solidified into the vitreous, this will leave pit of the vesicles. In order to prevent air bubble defect, generally should pay attention to the following procedures. (1) as far as possible to reduce firing can produce gas in the process factors. (2) reduce ball mill additives, these can be burnt in a gas or steam produced material. (3) reduce the bone porcelain glaze layer thickness can effectively shorten the time of the bubble discharge, the generation of small bubbles. (4) before firing, confirm the dry glazing products. (5) adjust speed, before 650 ℃, reduce speed as far as possible, so that you can before the bone porcelain glaze closed, fully ruled out. 6. Lower the temperature of the glaze burning, because some glaze, burnt. ( 2) Bone porcelain glaze missing bone porcelain of the phenomenon of local surface without glaze, glaze is products of the pinhole is much larger in size. On the edge of the unglazed glaze glaze layer protuberant crinkled with short phenomenon known as & other; Shrinkage glaze & throughout; Or & other Roll glaze & throughout; 。 The main reasons of lack of glaze is as follows. Formula (1) bone porcelain blank shaft does not adapt, poor wettability of glaze, glaze, high temperature viscosity and surface tension is too large. (2) the bone porcelain glaze slurry is too thick, glaze carefully. (3) glaze not before cleaning the dust, oil dirties, dirty, etc. (4) bone porcelain glazing is incomplete or handling take put in the process, make the bone porcelain glaze have a defect is not out. (5) with a kiln operation when he will wipe off glaze layer solution: can join in the bone porcelain slurries adhesives, bonding strength improve glaze. Lack of glaze bone porcelain products after partial grinding glaze glaze again after burn. ( 3) Glaze thin or dry bone porcelain glaze slurry density smaller or spray glaze spraying thin, glaze easy after burn, the phenomenon of the glaze thin or dry. Biscuit firing billet such as ShengShao or high temperature thermal insulation is too long and easy to dry enamel. Add high volatile organic colorant in glaze, make easy to check the quality of glazing after glazing. Use qualified biscuit firing billet. ( 4) Fried porcelain bone porcelain glaze expansion coefficient mismatch, bone China body for sintering, uneven thickness of bone China products, bone China design unreasonable, inappropriate firing system have may cause cracking products, also called Fried porcelain. According to the appearance of the crack is can distinguish between the temperature when Fried Fried porcelain porcelain or cooling. In low temperature stage, such as body break or burn before was not touching body are not ripe, moisture content is exorbitant, uneven body heat when heating, rapid easy cause Fried billet. After high temperature firing, the collapse of cracks open, but is covered by the glaze layer, fissure section is not sharp, local have glaze. Caused by cooling, rapid cooling phase of porcelain, the crack front. Often called the crack of the glaze has hair thickness & other Jing glaze & throughout; , when cooling, Fried porcelain reason is more, the bone porcelain glaze expansion coefficient mismatch, uneven thickness of bone China products, the shape design is not reasonable, cooling too quickly will cause. — Tangshan bone porcelain cup to be continued. 。 。 。 。 。