金属注射成形的脱脂临界厚度

Critical Thickness of Thermal Debinding in MIM

通过对脱脂动力学的分析,发现在脱脂过程中,存在动力学控制步骤转化的过程,提出了临界厚度的概念。临界厚度越大,意味着脱脂初始阶段升温速率可以较快,脱脂所需时间可以相对缩短。临界厚度越小,那么脱脂初始阶段必须缓慢升温,以免产生鼓泡、裂纹、变形等缺陷。生产实践中临界厚度越大,脱脂处理越容易进行。对脱脂过程中控制步骤的理论计算,得到脱脂临界厚度与粉末大小、脱脂温度和装载量的关系:临界厚度与粉末颗粒大小成正比,粉末颗粒越大,临界厚度也大;临界厚度与保温温度成反比关系,温度越高,临界厚度越小;临界厚度与装载量成反比,装载量越高,临界厚度越小。

By analyzing the kinetics of thermal debinding, shifting of different controlling mechanism was found in the debinding process. The definition of critical thickness was specifically put forward for the first in this article. Big critical thickness means fast initial heating can be performed, which means the time for debinding can be comparatively shorter. To avoid defects such as blisters, cracks and distortion, heating of compacts with small critical thickness should be very slow. In debinding practice big critical thickness is more favorable. Theoretical calculation of controlling steps show that critical thickness depends on the flowing factor: powder size, debinding temperature and solid loading; it's directly proportional to powder sizes, it's inversely proportional to temperature and solid loading rate.