Abstract: Usually the thermal expansion coefficients (TEC) of metals are higher than that of porcelains. In order to match the TECs in the case of coating porcelains on met-als, high TEC porcelains are needed. In this research, the high TEC phase leucite (KAISi2O6) in the high TEC porcelain was prepared by sol-gel method. The crystal size of leucite made by sol-gel is about 77nm through controlling the process parame-ters. The process from xerogel to leucite was investigated by means of DSC (differen-tial scanning calorimetry), TG (thermogravimetry), XRD ( X-ray diffraction) and IR (infrared absorption spectrum). Leucite had been detected after the gel was treated at 900℃, this formation temperature is about 250℃ lower than that of melting method.The porcelain made from 501166126174f the leucite powder and 5060f low fused temperature frit has an average TEC of 19.2×10^-6/℃ from room temperature to 450℃, which is much higher than the common porcelains.

Key words: thermal expansion coefficient, leucite, sol-gel, porcelain,