Effect of Si<sub>3</sub>N<sub>4</sub>-Nd<sub>2</sub>O<sub>3</sub> Compound Additive on Crystallization and Sintering of Fused Quartz Ceramic Materials

Abstract

Fused quartz granules (d50=19 μm) were used as raw material, and Si3N4-Nd2O3 (1:1, in mass) was used as additive with dosages of 1% (in mass, similarly hereinafter), 2% and 3%. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 °C, 1350 °C and 1400 °C for 1 h. The apparent porosity, bending strength and thermal expansion ratios of the samples were studied and the samples were further analysed by means of XRD and SEM. The results showed that the sample sintered at each temperature with 3% Si3N4-Nd2O3 had the lowest apparent porosity, the highest bending strength and more compact microstructure. This indicated that 3% Si3N4-Nd2O3 was useful to the sintering of fused quartz ceramic materials. The results of XRD and thermal expansion ratio analysis showed that 3% Si3N4-Nd2O3 compound additive had better effect on inhibiting crystallization of the samples sintered at 1300 °C, 1350 °C and 1400 °C.