氢气还原(W,Ni,Fe)复合氧化物粉末的物相变化研究

Study on phase transformation of(W,Ni,Fe) composite oxide powder in H_2-reduction process

以喷雾干燥法制备的(W,Ni,Fe)复合氧化物粉末为原料,在300～800 ℃间的不同温度点保温90 min的条件下用氢气进行还原.分别采用X射线衍射仪和高倍扫描电镜对还原粉末进行了物相分析和形貌观察,并用TC-436氮/氧分析仪对还原粉末的氧含量进行了测试.结果表明:在300～350 ℃时,出现Ni相;400～450 ℃时,出现Fe相;在450 ℃时出现γ-(Ni,Fe)相;500 ℃时出现W相;600 ℃时形成稳定的W相和γ-(Ni,Fe)相; 在300～650 ℃间氧含量随温度的升高由20.77 %降至0.46%,并在700～800 ℃基本平衡在0.20 %左右.

（W,Ni, Fe） composite oxide powder synthesized by spray drying was reduced at different temperature in the range of 300～800℃ for 90 minutes in H2 atmosphere. Phase oomposition and particle morphology of the redued powder were measured by X-ray diffraction and SEM, respectively. Oxide content of the reduced powder were also measured by TC-436 nitrogen/oxide analysis apparatus. The result shows that： The phase Ni, Fe, γ-（Ni,Fe） ,W appear at 300～350℃, 400～450℃, 450℃, 500℃, respectively. Stable W and γ-（Ni,Fe） phases are formed at 600℃. With increasing of the reduction temperature, oxide oontent of the reduced powder decreases from 20.77% to 0.46% at temperature between 300℃ and 650℃ and is stable （0.20%） at temperature between 700℃ and 800℃.