单质导电材料SPS过程中颈部形成机理

Mechanism of neck formation of conductive pure materials during SPS

研究了单质导电材料在放电等离子烧结(SPS)过程中颈部形成的机理。以纯铜粉末为例,研究不同烧结阶段的显微组织特征,并建立描述颈部形成机理的两颗粒模型,计算从颗粒几何中心到两颗粒接触点的温度分布。结果表明,颗粒内的温度分布极不均匀,颈部区域的温度可以达到材料的熔点甚至沸点。因此,SPS过程中颈部形成的根本原因是瞬时局部高温造成颗粒接触部位的熔化甚至汽化,形成粘结。

The mechanism of neck formation of conductive pure materials during SPS was studied. By using the pure copper powders as the sintering material, the microstructure characteristics of different sintering stages were studied and discussed. A two-particle model was developed to describe the temperature distribution from the center to the contact area of two particles. It is concluded from the present model that, there is a greatly inhomogeneous distribution of the temperature in the particle, the temperature is higher than the melting point even boiling point of the material in neck zone. Consequently, the essence of the neck formation is the melting and even vaporizing of the contacting area between particles due to the local extra high temperature.