埋粉对热脱脂速率和传质过程的影响

Influence of Powder Bed on Thermal Debinding Rate and Mass Transport Process

对比了活性碳、γ-Al2O3、ZrO2粉、α-Al2O3和刚玉等5种埋粉对热脱脂中低分子量粘结剂脱除速率及传质过程的影响。结果表明比表面积高的活性碳和γ-Al2O3对脱脂的促进作用可以保持低分子量粘结剂脱除的整个过程,而低比表面积的刚玉粉、α-Al2O3粉、ZrO2粉则只在起始阶段起作用。空气气氛和低比表面积埋粉的热脱脂过程可以用扩散传质方程描述,而高比表面积埋粉对传质的促进作用体现在液相抽吸和气体吸附两个方面,气体吸附作用不能在扩散方程中得到体现。

The influence of five kinds of powder bed, activated carbon, γ-Al2O3, ZrO2,α-Al2O3 and corundum on thermal debinding rate and mass transport process was studied. The results showed that powder bed with high specific surface area, activated carbon and γ-Al2O3 increased the thermal debinding rate in the whole process, but the powder bed with low specific surface area had this effect only in the initial stage. The melted binder can be sucked away from the compact under the capillary effect and the vapor products can be absorbed by the powder bed with high specific surface area.