抄録
The combustion synthesis was applied to preparing ZrNi using elemental powder mixtures in a vacuum of 10−4 Pa and at initial temperatures of 298–673 K. The combustion synthesis at initial temperatures not exceeding 373 K yielded porous products, whereas the combustion synthesis at the initial temperature of 673 K yielded an ingot type product. The propagation rate of the combustion wave was 9.9 mm/s, the maximum combustion temperature was 1483 K and the maximum heating rate was 1730 K/s in the case of the initial temperature of 373 K. No change in the oxygen content of the sample was observed before and after the combustion synthesis. Products of the combustion synthesis contained ZrNi, Ni11Zr9 and Zr2Ni in all the conditions investigated. The difference in nickel particle size caused no conspicuous differences in the amount of the phases in the products. The conversion ratios of the powder mixtures to ZrNi were approximately 0.75 and 0.88 in the case of initial temperatures of 373 and 673 K, respectively. It is considered in the combustion synthesis of ZrNi that the zirconium-rich liquid phase with 76 at.% of zirconium and the nickel-rich liquid phase with 36 at.% of zirconium were produced in the initial stage of the process and then the two liquid phases reacted each other to form ZrNi.
