Micro powder injection moulding of alumina micro-channel part

A feedstock consisting of submicron alumina powder and a formulated binder, was developed to fabricate alumina micro-channel part by micro powder injection moulding. During small scale-mixing, the mixing torques of feedstocks with four different powder loadings were used to establish a suitable powder loading. The thermal and rheological properties of the selected feedstock were examined and used to establish conditions for large scale mixing, debinding and injection moulding. The micro-channel parts were pressureless sintered at different temperatures. The results showed that the moulded, debound and sintered micro-channel parts had good shape retention. The dimensions of the micro-channel part changed with the different processing steps. High densification of the micro-channel parts was achieved at sintering temperatures of 1350 °C and above. Above 1350 °C, the grain grew significantly with increasing the sintering temperatures and thus it led to a decrease in the microhardness.