电容器钽粉镁处理降氧工艺探究

本文探讨了钽粉镁处理降氧工艺:钽粉与还原剂镁粉充分混合,在真空或惰性气氛下800～950℃还原反应,出炉后酸洗除去残余还原剂等杂质。从加镁量、反应温度、反应时间、掺氮等参数分析影响降氧效果的各因素。通过对比试验得出:加镁量要稍过量,为钽粉含氧重量的300%为宜;反应温度在900℃以下降氧效果不明显,反应温度越高,降氧效果越好,但温度过高会减少钽粉比表面积,导致比容降低;反应时间需≥3h,时间过短反应不充分,达不到降氧效果;反应完后掺入杂质氮可以降低钽粉中氧含量,出炉前用一定比例的氧气钝化钽粉,可以增强降氧效果。并通过工艺实践,确定了镁处理降氧的最佳工艺参数。

Research on Deoxidization of Electrolytic Tantalum Powders by Magnesium Reduction

The oxygen reduced treatment of tantalum powders was discussed in this article.Tantalum powders were mixed with magnesium powder,reacting at the temperature of 800～950 ℃ in vacuum or an atmosphere of argon.After the reduction,the impurity like superfluous magnesium was removed by acid pickling.The effects of oxygen reduced treatment from dosage of magnesium,the temperature of reaction,the time of reaction,nitrogen adulterating,etc,were analyzed in this article.The result of comparative trial shows that the dosage of magnesium should be excessive.It is appropriate that the dosage of magnesium should be three times of the weight of oxygen.The result of deoxidization is not evident when the temperature of reaction is below 900 ℃.The higher the temperature is,the better the result of deoxidization will be.However,if the temperature is too high,the BET and the CV of tantalum powder will descend.The time of reaction must be at least 3 h.Otherwise,it can't ensure the effect of deoxidization.Nitrogen doping is good for deoxidization after the treatment.Tantalum powders are passivated by a certain percentage of oxygen after reaction,which can enhance the deoxidization effect.The optimal technology parameters are determined by process practice.