烧结温度对钽电容器阳极坯块性能的影响
来源期刊：中南大学学报(自然科学版)1986年第2期
论文作者：娄燕雄 刘贵材
文章页码：44 - 51
关键词：钽电容器； 电容量； 线材； 烧结； 抗脆性
Key words：tantalum； capacitor； capacitance； wire； sintering； anti-embrittlement.
摘 要：以两种不同纯度的钽粉为原料,配六种不同类型的钽丝为引线,压制成形并以五种温度分别进行烧结,然后,测其电容量、漏电流、孔隙度以及引线的抗脆能力、硬度并取其金相组织。由数据可知,随烧结温度提高,电容量降低,漏电流减少。当烧结温度超过1800℃时,漏电流降低至×10-4μA/μF·V;当超过1900℃时,电容量和孔隙度都趋于稳定,但烧结温度提高,引线的抗脆能力变差,并在1900℃时不合格的几率最大。这证明,烧结温度对材料的电性与抗脆性有明显的影响。由数据可知,以掺杂钽丝作引线的坯块,其电性符合要求,抗脆性也得到改善。掺杂钽丝和钠还原钽粉制的纯钽丝,其抗脆性优于碳还原钽粉制的纯钽丝和以熔炼锭坯制的纯钽丝,由金相照片可见,易脆引线的晶粒粗大且晶界平直,而抗脆好的引线,其晶粒细小井呈细条状或纤维状。由硬度可知,坯块中的气体杂质向引线渗透。
Abstract: Anodes are made of Ta powder of 2 kinds of different purity and matched with Ta leads of 6 different kinds. After pressing, anodes are sintered with 5 various temperatures. Then, the capacitance, leakage and porosity of anodes and anti-embrittlement and hardness of leads are mea- sured. The microstructure of leads is also investigated. The experimental data show that the capacitance and leakage decrease as the sintering tem- perature increases. When the sintering temperature rises above 1800℃ the leakage drops to×10-4μA/μF·V level, above 1900℃ the capacitance and porosity tend towards stabilization. At 1900℃, however, anti-embrittlement of Taleads is the worst, and probability of fail is maximum. It confirms that under certain sintering temperature, the favourable electrical performance and the best anti-embrittlement are conflict with each other. Doped Ta leads have no influence on electrical performance of anodos but it is beneficial to anti--embrittlement of leads. The anti-embrittlement of Ta wire that is doped and/or made from sodium reduced powders is much better than that of Ta wire made from carbon reduced powders and/or made by electron beam melting ingots. The microstructures indicate that there are coarse grains with flat boundaries in the embrittle leads while there are fine and fibre grains in the ductile leads. From the data of hardness we can see that the gas impurity in anode has diffused into the leads （Figures 6 and Tables 10）
