Fabrication of Sintered Compacts with High Hardness and High Corrosion Resistance Using the Water-Atomised Ferritic Nickel-Free Stainless Steel Powder

The austenitic stainless steel used for the exterior parts contains Ni, which causes metal allergies, so there was a need for a Ni-free stainless steel. On the other hand, ferritic stainless steel does not contain Ni in its alloy, so it does not cause metal allergies, but it is said that its corrosion resistance is inferior than austenitic stainless steel because of a weaker passive film.In addition, the sintered compacts producted by metal injection molding have micropores inside, so their corrosion resistance are lower than the wrought, and they are susceptible to scratches because of a low hardness of 180 to 200 Hv. Therefore, we conducted research to improve both the corrosion resistance and hardness of sintered compacts using the water-atomised ferritic nickel-free stainless steel powder by MIM, which can produce near net shape parts.