Fe-Cr-W复合氧化物粉末共还原工艺研究

Reduction Processing of Fe-18Cr-9W Composite Oxide Powder

通过H2-CO共还原法对Fe-18Cr-9W复合氧化物粉末进行还原,控制还原工艺的参数制得纳米级Fe-18Cr-9W复合粉末.采用XRD对粉末进行物相分析,并计算晶粒尺寸;采用高倍SEM观察粉末形貌;对复合粉末的费氏粒度、比表面面积、氧含量等进行测定与分析,研究还原温度和还原时间对粉末性能的影响.研究结果表明:当还原温度高于650℃时制得的复合粉末由Fe和Fe-(Cr,W)两相组成;粉末颗粒呈球形或近球形;还原温度和还原时间都对Fe-18Cr-9W复合粉末的性能有显著影响,当还原温度为700℃,还原时间为90 min时,制备的颗粒为平均费氏粒度低于0.58μm,平均BET粒度小于80 nm,晶粒粒径小于50 nm,粉末氧含量小于0.14%的纳米级Fe-18Cr-9W复合粉末.

Fe-18Cr-9W nanometer composite powder is produced by the method of co-reduction of Fe-18Cr-9W composite oxide powder, in which the procedure parameters are controlled. Phase composition, crystalline size and particle morphology of the powder were measured by X-ray diffraction and SEM. Fsss particle size, special surface area and oxide content of reduced powder are also measured. The effects of the reduction temperature and reduction time on the properties of the composite powder are studied. The results indicate that the phases of the composite powder reduced at high temperature above 6500C contain Fe and （Cr , W） ; the particle morphology is spherical or nearly spherical ; the properties of the reduced powder are greatly affected by the temperature and time of the reduction process , and the best properties of the composite powder can be obtained at 700℃ for 120 min ; nanometer Fe-18Cr-9W composite powder with Fsss particle size smaller than 0.58μm , BET particle size smaller than 80 nm , crystalline size smaller than 50 nm and oxide content of reduced powder smaller than 0.14 % is synthesized.