真空碳热还原制备碳化钛和碳化铌粉体的研究

Study on Preparation of TiC and NbC Powder by Vacuum Carbothermal Reduction

对TiO2和Nb2O5混合球磨料采用真空碳热还原法制得了TiC和NbC,通过正交实验研究了Nb2O5、TiO2和活性炭混合料的摩尔配比、混料球磨时间、还原温度和还原时间对制备TiC和NbC的影响,运用激光粒度仪、X射线衍射仪(XRD)以及扫描电子显微镜(SEM)对混合料和还原产物的粒度、物相及微观形貌进行分析。实验结果表明,各因素对还原程度的影响由大到小顺序为:还原温度>混合料球磨时间>混合料Nb2O5∶TiO2∶C摩尔配比>还原时间,优化实验条件为:混合料Nb2O5∶TiO2∶C摩尔配比1∶3∶20,混合料球磨时间10 h,还原温度1 600℃,还原时间2 h。在该条件下,Nb2O5和TiO2混合料的还原率达到93.90%。真空碳热还原TiO2和Nb2O5混合料比单独还原Nb2O5所需的温度更低,且不需要二次还原,即可得到较纯的TiC和NbC。另外,增加TiO2和活性炭含量,还原产物的粒度更细,可达到纳米级。

TiC and NbC were prepared by vacuum carbothermal reduction of TiO2 and Nb2O5 ball-milled mixture.The effects of molar ratio of TiO2,Nb2O5 and activated carbon,milling time,reduction temperature and reduction time on the preparation of NbC and TiC were studied by orthogonal experiments.The particle size,phase and micro morphology of the mixture and reduction products were analyzed by laser particle size analyzer,X-ray diffractometer(XRD) and scanning electron microscope(SEM).The results show that the order of the influence of the factors on reduction rate is as follows:reduction temperature > milling time of mixture > molar ratio of Nb2O5∶TiO2∶C > reduction time.The optimized experimental conditions are Nb2O5 ∶TiO2 ∶C molar ratio of 1∶3∶20,milling time of 10 h,reduction temperature of 1 600 ℃,and reduction time of 2 h.Under these conditions,the reduction rate of Nb2O5 and TiO2 mixture reaches 93.90%.Vacuum carbothermal reduction of Nb2O5 and TiO2 mixture requires lower temperature than that of Nb2O5 alone,and pure TiC and NbC can be obtained without secondary reduction.In addition,with the increase of the content of TiO2 and activated carbon,the particle size of the reduction product is finer and can reach the nanometer level.