Fabrication and Characterization of the Sintered Compact Using Water-atomized Ferritic Stainless-steel Powder by Metal Injection Molding

Austenitic stainless steel SUS304L and SUS316L are used in exterior parts of watches and clocks from the viewpoints of mirror-like surface and corrosion resistance. The austenitic stainless steel contains about 10 to 14 mass% Ni, which is a cause of metal allergy, and there has been a demand for Ni-free stainless steel that does not affect human skin while maintaining mirror finish and corrosion resistance. In sintered compacts made using the metal injection molding method, a dense layer with no inclusions is formed only 50 to 100 µm from the surface layer. Therefore, even if they are polished, microscopic pores are present on the surface, and a high-quality mirror-like surface couldn't be obtained. In this study, we investigated fabrication that reduces inclusions from the surface layer of Ni-free stainless steel and evaluated characterization of the sintered compacts.