Influence of Sintering Atmosphere on the Hardness and Corrosion Resistance of 17-4 PH Stainless Steel Formed by the Powder Molding Injection Process

This research study aims to evaluate the influence of the sintering atmosphere on the hardness and corrosion resistance of 17-4 PH stainless steel alloy. The removal of the primary binder was carried out by chemical extraction applying a solvent with less environmental impact, which has proved to be suitable for this purpose. The subsequent binder thermal extraction was held by heating at temperatures of 250°C and 450°C and, afterwards, at temperature of 900°C, to initiate sintering. Nitrogen, vacuum and hydrogen atmospheres were used with sintering temperatures at 1250°C and 1330°, with 30 and 60 minute-step time. It was verified that the densities achieved in hydrogen and vacuum atmospheres are similar and suitable by the standards, whereas the nitrogen atmosphere resulted in lower performance. The hardness and corrosion resistance obtained with the use of hydrogen and vacuum atmospheres were also higher than those obtained for samples sintered in the nitrogen atmosphere.