Fabrication of zero-thermal-expansion ZrSiO4/Y2W3O12 sintered body

We focused on the linear negative thermal expansion of Y2W3O12 in a wide-temperature range and on the chemical stability of ZrSiO4 in the fabrication of the composite material ZrSiO4/Y2W3O12 with a zero-thermal-expansion. The compact composed of Y2W3O12 and ZrSiO4 had a thermal shrinkage rate smaller than that of Y2W3O12 and higher than that of ZrSiO4. SEM-EDX observation clarified that the ZrSiO4/Y2W3O12 sintered body fabricated at 1400 degrees C for 10 h had a microstructure composed of ZrSiO4 and Y2W3O12 grains, and XRD indicated that only ZrSiO4 and Y2W3O12 phases existed in the sintered body. The relative density of the ZrSiO4/Y2W3O12 sintered body reached 92%, which was larger than that of the ZrSiO4 sintered body because Y2W3O12 grains could be sintered at lower temperatures. The average linear thermal expansion coefficients of the ZrSiO4/Y2W3O12 sintered body were -0.4 x 10(-6) and -0.08 x 10(-6)degrees C-1 in the temperature ranges from 25 to 500 degrees C and from 25 to 1000 degrees C, respectively, which showed an almost zero-thermal-expansion. (C) 2009 Elsevier Ltd. All rights reserved.