粉末微注射成形ZrO_2微结构表面质量控制

Control of the surface quality for ZrO_2 microstructures by powder micro-injection molding

采用粉末微注射成形技术制得了二氧化锆陶瓷微结构件,注射成形最小微结构尺寸为Φ300μm×250μm.分析了微注射成形工艺参数、模具抽真空及硅模具对微结构表面质量的影响.实验结果表明在模具温度和注射压力较低时,相同工艺参数下随着微型腔尺寸的减小微结构顶端的表面平整度逐渐下降,提高模具温度和注射压力以及注射前对模具进行抽真空可以改善微结构表面平整度.另外,注射前的模具抽真空有助于减少微结构的表面气孔.亚微米陶瓷超细粉的使用明显改善了烧结后微结构的表面质量,其表面粗糙度值由烧结前的0.33μm降低为约0.28μm.

A ZrO2 ceramic microstructured part with the minimum size of Φ300 μm × 250 μm was fabricated by powder micro-injection molding process. The effects of injection parameters,mold vacuum and silicon mold on the surface quality of microstructures were analyzed. Test results indicate that the tip of microstructures becomes more uneven with the decrease of micro-cavity size under the same injection parameters. The difference of surface quality among microstructures with different sizes can be eliminated by increasing injection pressure and mold temperature or vacuumizing mold before the injection stage. On the other hand,mold vacuum can avoid air holes on the surface of microstructures. Sub-micron ZrO2 powder improves the surface roughness of sintered ceramic microstructures from 0. 33 μm of the green part to 0. 28 μm.