选择性激光烧结/冷等静压复合制造高密度Al2O3异形陶瓷件的研究

为了获得高密度复杂形状氧化铝陶瓷件,提出采用覆膜和混合相结合的方式制备出含有机粘接剂w(PVA)=1.5%和w(ER06)=8.0%的Al2O3复合粉体,对复合粉体进行选择性激光烧结(selective laser sintering,SLS)/冷等静压(cold isostatic pressing,CIP)成形、再经脱脂、高温烧结获得最终陶瓷零部件的制造方法。研究了激光烧结的4个工艺参数,得出在激光功率为21 W、扫描速度为1 600 mm/s、扫描间距为100μm、单层层厚为150μm时,获得的SLS陶瓷坯体密度和强度较好,较高强度的SLS坯体有利于后续其它工艺的进行。研究了具有随形包套的SLS陶瓷件的CIP工艺,得出随着压力的增大,陶瓷坯体的孔隙得到更大程度的消除,粉体颗粒重排压实,密度和强度显著提高,而当CIP压力大于200 MPa时,致密化速率减小。基于环氧树脂粘接剂的热重(TG)曲线分析,对SLS/CIP试样进行合理的脱脂、高温烧结处理,所得Al2O3陶瓷件相对密度大于92.26%。为制造高性能复杂形状的陶瓷件提供了一种新的方法,并拓展了SLS技术的应用范围。

Densification of Alumina Components Via Indirect Selective Laser Sintering Combined with Isostatic Pressing

In order to improve the final density of ceramic parts via indirect selective laser sintering (SLS), cold isostatic pressing (CIP) technology was introduced into the process. In SLS/CIP/Sintering compound process, a combination method of spray drying and mechanical mixing was proposed to prepare polyvinyl alcohol (PVA, 1.5wt%)-epoxy resin E06 (8wt%) system alumina compound powder with good fluidity for SLS. When the laser power, scanning velocity, scanning spacing, layer thickness was 21 w, 1 600 mm/s, 100 μm,150 μm, the SLS parts had the highest relative density which was good for the following operation and final density. A soft polymer canning was prepared for CIP around the surface of SLS alumina ceramic parts. As CIP maximum pressure increased, more and more pores in alumina were closed and particles were rearranged and compacted. But when CIP maximum pressure reached 200MPa, the densification rate of SLS alumina parts became smaller. According to TG curve of epoxy resin E06, green bodies were degreased and furnace sintered. Finally, the relative density of alumina parts reached 92.26% after Sintering process. The study was helpful for manufacturing complex shape ceramic matrix and ceramic components by indirect SLS technology for engineering application.