The effect of the amount of filler in iron on corrosion

Abstract

The influence of the quantity of polymeric binder in the sintering of commercially obtained iron powder was investigated. Hydrogen-reduced iron powder with grain sizes below 50 µm was mixed with spherical polystyrene dissolved in 5 cm3 of acetone. The resulting dough-like mixture was cast into a mold and subsequently dried at 37 °C. After drying, a two-phase firing process was carried out in a protective argon atmosphere. The fired samples were immersed in a 0.9% NaCl solution, and their corrosion current was continuously monitored. The use of polystyrene as a binder offers the advantage of maintaining a stable shape both after drying and firing. Dimensional stability is preserved. Three different quantities of polystyrene, namely 0.5 g, 1.0 g, and 1.5 g, were used. The amount of added polystyrene influenced both the microscopic structure and the measured corrosion current. This research highlights the significance of binder selection and quantity in achieving the desired properties of iron powder compacts, emphasizing the pivotal role played by polymeric binders in the powder metallurgy process.