[T7] AM Sinter Based Technologies

[16A-T7-17] Densification of Metal BJT Parts with Fine Grains Coated with Fine Powder

*K. Kariya¹, T. Osada¹, J. Saruta^{1, 2}, S. Kobayashi¹ (1.Tokyo Metropolitan University, Japan, 2.ASK Chemicals Japan Co., Ltd., Japan)

キーワード：Additive Manufacturing, Binder Jetting, Hot Isostatic Pressing, Densification, Slurry Coating

Binder jetting (: BJT) metal additive manufacturing uses binder to bind metal powders and build metal parts selectively. BJT has low equipment costs and is highly scalable. However, parts printed by BJT process are difficult to be high density. Conventional densification methods require high temperature and long sintering time, but this method results in larger grains and lower strength of sintered compacts. Therefore, both densification and fine grains are necessary. We manufactured pre-sintered bodies at low temperatures, and hot isostatic pressing (: HIP) them. However, pre-sintered bodies at low temperatures have interconnected open pores. If there are interconnected open pores HIP can’t ensure density. Therefore, we attempted to eliminate the interconnected open pores by coating with slurry using fine powder. The fine powder on the surface becomes high density and eliminates interconnected open pores at relatively low sintered temperature. As a result, we got high density and fine-grained specimens.