Adjustable Thermal Expansion Properties in Zr(2)MoP(2)O(12)/ZrO(2) Ceramic Composites

Zr(2)MoP(2)O(12)/ZrO(2) composites were successfully synthesized by the solid state method in attempt to fabricate the near-zero thermal expansion ceramics. The phase composition, micromorphology and thermal expansion behavior of the Zr(2)MoP(2)O(12)/ZrO(2) composites with different mass ratios were investigated using X-ray diffraction, scanning electron microscopy and thermal mechanical analysis. Results indicate that Zr(2)MoP(2)O(12)/ZrO(2) composites can be prepared by pre-sintering at 500°C for 3 h and then sintering at 1050°C for 6 h. The resulting Zr(2)MoP(2)O(12)/ZrO(2) composites consisted of orthorhombic Zr(2)MoP(2)O(12) and monoclinic ZrO(2). With increasing content of Zr(2)MoP(2)O(12), the Zr(2)MoP(2)O(12)/ZrO(2) ceramics became more compact and the coefficient of thermal expansion decreased gradually. Zr(2)MoP(2)O(12)/ZrO(2) composites show an adjustable coefficient of thermal expansion (CTE) from 5.57 × 10(−6) K(−1) to −5.73 × 10(−6) K(−1) by changing the mass ratio of Zr(2)MoP(2)O(12) and ZrO(2). The Zr(2)MoP(2)O(12)/ZrO(2) composite with a mass ratio of 2:1 showed near zero thermal expansion, and the average linear thermal expansion coefficient is measured to be 0.0065 × 10(−6) K(−1) in the temperature range from 25 to 700°C.