Abstract:
In order to investigate the thermology properties of Ni-based Y
2W
3O
12 composites, negative thermal expansion material Y
2W
3O
12 was prepared by secondary solid-state method firstly. Then, Y
2W
3O
12 was mixed with metal Ni, and by hot pressing sintering under the conditions of 1 200 ℃ and 50 MPa, 40vol% Y
2W
3O
12/Ni composites were obtained. Finally, the compositions and thermal expansion properties of composites were investigated. The results indicate that during the hot pressing sintering process, comparing with the complex chemical reactions occurring in contrast sample 40vol% Y
2W
3O
12/Cr composite, there is no reaction occurred between the two phases of 40vol% Y
2W
3O
12/Ni composites, for the reducibility of Ni is weaker than that of W, which makes 40vol% Y
2W
3O
12/Ni composite keeps the lower coefficient of thermal expansion. After several cycle annealing to release the thermal stress and remove the crystal water of Y
2W
3O
12 phase, the coefficient of thermal expansion of 40vol% Y
2W
3O
12/Ni composite in the temperature range of 170-800 ℃ tends to be stable, which is about 3.4×10
-6 K
-1 and close to the theoretical design value of 4.0×10
-6 K
-1.