Influence of Rare earth oxides on Crystallization behavior and Sintering performance of Fused Quartz Ceramic Materials

Fused quartz granule (d(50)=0.033mm) was used as raw material, Pr6O11, Sm2O3, Gd2O3, Dy2O3 and Ho2O3 were used as additives with dosage of 2% each. Fused quartz ceramic materials were fabricated in reduction atmosphere at 1300 degrees C, 1400 degrees C and 1500 degrees C for 1h. Samples were examined apparent porosity, bending strength, thermal expansion rate (RT similar to 200 degrees C), and analyzed by XRD and SEM. The results indicated that additives Pr6O11, Sm2O3 and Dy2O3 had a bit inhibiting effect on crystallization of fused quartz sintered at 1300 degrees C and 1400 degrees C, Ho2O3 and Gd2O3 had more inhibiting effect on crystallization in samples sintered at various temperatures, sample containing Ho2O3 had least thermal expansion rate. Pr6O11, Sm2O3 and Dy2O3 had few facilitating effect on sintering, Gd2O3 and Ho2O3 had more facilitating effect on sintering of fused quartz ceramic materials, samples with Gd2O3 and Ho2O3 had lower apparent porosity and higher bending strength and more compact microstructure. It can be deduced that Gd2O3 and Ho2O3 play the excellent role as the crystallization inhibitor to fused quartz materials.