Production and aging of highly porous 17-4 PH stainless steel

This study describes production of highly porous 17-4 PH stainless steel for biomedical implant applications by space holder-sintering technique. 17-4 PH stainless steel powders were mixed with space holder and then compacted. For designing pore properties, both spherical and irregular shaped carbamide with different particle size ranges were used as space holder and removed by water leaching. Porous 17-4 PH steel specimens were sintered at 1,260 °C for 40 min. Boron was used as a liquid phase sintering additive. In addition, sintered specimens were aged in order to increase mechanical properties. Specimens were austenitized at 1,050 °C and then quenched. Quenched specimens were aged at times of 1–6 h at temperatures between 450 and 570 °C. The pore size and shape of the 17-4 PH stainless steel foams replicated the initial size and shape of the carbamide particles. This suggests that pore properties can be designed by using proper size, shape and content of space holder.