The effect of cellulose-derived binder on properties and performance of PM steels

A room-temperature extrusion technique, originally developed for the extrusion of ceramic powders, has been adapted to the extrusion of metal powders. The extrusion technology relies on cellulose-derived binders, which in traditional ceramic practices are burned off during sintering in air. In this work, the influence of hydrogen-debinding on density, carbon and oxygen levels is studied by comparing the effects of hydrogen debinding with the effects of air-debinding in as-debound and as-sintered samples. The study found debinding in hydrogen to result in significant levels of residual carbon, which promote austenite at the sintering temperature, and reduce densification. Debinding in air was effective, resulting in very low carbon concentrations and densification of up to 97 vol.-%, but also a considerable amount of oxides, which were not completely reduced during hydrogen sintering.