Display the bone China defect 18

Bone porcelain glaze melt temperature is too high, or the sintering temperature is not enough, or gas and impurities in the underside volatile also can produce pinhole. Bone porcelain glaze, high temperature viscosity ( The bone porcelain glaze composition particle fineness and flow performance) When the bone porcelain glaze layer discharge gas, appeared at the beginning of vesicles, as temperatures continue to rise, big bubble was melted away, and vesicles were left, cause the pinhole. ( 3) No glaze billet adhesion with organic matter and small grain of dust, firing, small grain of dust particles and organic matter after burn off and leave a small amount of ash grain, bone porcelain glaze formation pore. Sometimes when the inorganic matter ( Sand) Attached to the bone China body surface will also have the same damage. ( 4) Bone porcelain glazing, bone porcelain body is too dry and hydrating uneven or not, the bone porcelain glaze for bone China body evenly absorbed, produce bone porcelain glaze pinhole. Bone China body wet on glaze and not dry burning, burning, the water vapour to escape in great quantities, it is easy to produce pinhole, if warming up a blister. Bone porcelain glaze layer thickness, if too thin, too bone porcelain glaze pulp thick, not only easy to generate crack glaze and closed porosity caused a pinhole. ( 5) Paired pinhole at low temperature, the influence of fire, burning not fully, the bone porcelain body on deposit, when high temperature with the increase of excess air coefficient is burnt, leaving the pinhole. Burning high temperature stage, from the eduction in bone porcelain glaze billet more gas, break through the thick glaze, bone porcelain glaze to fusion or bone porcelain glaze liquid surface tension is too small and leaving holes. Followed by and is expected to start melting temperature is too low, the partial melting glaze is absorbed by porous body; Or raw glaze glaze cracking ( Micro crack) Failed to fusion, or sintering temperature is not enough, not fully melted evenly spread. Too early, atmosphere is too heavy and too long, easy to produce pinhole. Due to the forced ventilation, ashes too much, water vapor, may also cause a pinhole. ( 6) Affected by the sulfurous acid gas because of sulfurous acid ( H2SO3) Escape in the process of heat decomposition of sulfur dioxide gas to the bone China products can also cause a pinhole overcome way: ( 1) Bone porcelain glaze composition and preparation: as far as possible choose contain organic impurities less clay, and through the elutriation, impurities such as organic matter, want to have full of stale period. Bone China clay glaze mixing too fast, in case of air in a bubble. Mud glue solution of sodium silicate and sodium carbonate used in combination is better. The proportion of bone porcelain glaze slurry control, black and white glaze; Mechanical operation the glaze proportion generally to 1. 58 - 1. 65, hand touch glaze, the proportion should be 1. 45 - 1. About 55. Bone porcelain glaze proportion according to the different varieties of bone China. ( Refer to the attached list) ( 2) Bone China before billet into the box, to clean the dust miscellaneous bone porcelain body. ( 3) When burnt, strictly implement the system of burning, bone porcelain glaze should fully molten, vitrified bone porcelain glaze melting flat. Using low sulfur fuel. ( Refer to the chapter & other; White glazed porcelain pinhole & throughout; ) — Tangshan bone porcelain furnishing articles gift is gone. 。 。 。 。 。