Study On Deformation Controlling Of High-transparency Domestic Porcelain Product

High-transparency domestic porcelain was practical,commercial,artistic,and belonged to the category of high-grade domestic porcelain.In order to obtain high transmittance,potassium or sodium feldspar was introduced to produce large amounts of transparent liquid phase.However,excessive liquid phase caused defects of porcelain as pyroplastic deformation and crack during sintering process.Therefore,there was still no solution of the contradiction between high transmittance and low deformation,which determine the quality of high transmittance domestic porcelain.The Associated Albite Kaolin（AAK）with 3.35wt%Na₂O produced in Yunnan and Guizhou could be able to calinated into porcelain without adding flux,while the massive using of AAK would inevitably lead to the pyroplastic deformation of porcelain body,due to the mass percentage of Na₂O introduced into porcelain from AAK is much higher than that in traditional domestic porcelain,based on the least content required for porcelain producing.It was necessary to carry out the relevant application research on deformation control of porcelain body.In the present study,the effect of transmittance and pyroplastic deformation was investigated by adjusting the amount of Na₂O,adding 58μmα-Al₂O₃and regulating Ternary flux composite system as the AAK was the main raw material in porcelain.And process parameters were optimized.First,the effect of Na₂O contents on transmittance and pyroplastic deformation was elucidated and the maximum contents was confirmed.Second,the effect ofα-Al₂O₃contents on inhibiting pyroplastic deformation and transmittance was clarified.Third,the effect of pyroplastic deformation and transmittance was analyzed,based on regulating Ternary Flux Composite System by adding sintered talc.Finally,the transparent glaze was fabricated according to the results of orthogonal experiments,which revealed the effect of quarts,frits and granule glass on properties of glaze and the optimal contents was also defined.The results showed:（1）The transmittance and pyroplastic deformation index of high-transparent porcelain with using 30wt%AAK,4wt%58μmα-Al₂O₃,0.5wt%sintered talc was13.04%and 3.16×10^-6mm^-1after sintering at 1310℃,whose transmittance was20.52%higher than commercial product and the pyroplastic deformation index was lower than that.The contradiction between transmittance and pyroplastic deformation had been solved.（2）Transparent glaze with gloss of 100%,glaze hardness of 6.26GPa,no pinhole and heating transfer after 20～200℃without cracks was prepared by optimizing process parameters.（3）Due to sodium feldspar particles was inserted into the lamellar kaolinite,the low viscosity liquid phase generated by the Na₂O was dispersed into the porcelain body homogeneously and maintain discontinuous characteristic as the barrier of lamellar kaolinite.This phenomenon mitigated the deformation at the beginning of densification.As the temperature increased,the increasing liquid phases melted the lamellar kaolinite and formatted needle-shape mullite,which is not enough to resist the creep caused by gravity.Thanks to the homogeneous dispersedα-Al₂O₃particles,it inhibited contaction between liquid phase,decreased the concentration of liquid phases and enhanced the resistance to pyroplastic deformation.Moreover,liquid phase with melting talc increased the refractive index,narrowed the refractive index gap between liquid phase and crystal phase and improved the transmittance of porcelain.