摘要
研究了不同形状和尺寸的预成形模具对负温度系数热敏电阻材料试样的生坯密度和烧结密度均匀性、成品阻值合格率以及芯片老化性能的影响。结果表明:同样的装粉量和装粉密度情况下,采用方形模具压制出的生坯内外密度的均匀性比圆形模具好;同是方形模具时,模腔尺寸越大,生坯内外密度差异越大。2种模具压制生坯的密度差异在烧结后都不能完全消除。试样密度差异越大,芯片的老化率也越高。采用方形预成形模具,模腔尺寸40mm×40mm×40mm,装粉量110g,能够达到生产效率和合格率的统一。
The role of preforming mould in the manufacuring process of negtive temperature coefficient （NTC）thermistor was focused on.The effects of the shape and size of the preforming mould on the homogeneity of compact density and sintered density,the yield of finished product and aging properties were studied.The results show that the density uniformity of compact pressed with square mould is better than that with round mould under the same filling amount and the same apperant density.In the case of square mould,the density uniformity of compact pressed with smaller mould is better than that with larger mould.And the density nonuniformity can not be eliminated after the sintering process.In addition,the NTC chip made from central section of the sample has a worse aging property because of its lower density.The aging rate decreases with the density uniformity increasing.The final experiments also reveal that square shape is the suitable shape for preforming mould,and the optimal size is 40mm × 40mm × 40mm and the filling amount is 110g.
出处
《粉末冶金技术》
CAS
CSCD
北大核心
2013年第6期424-428,共5页
Powder Metallurgy Technology
