REMOVAL OF LOW-MOLECULAR-WEIGHT COMPONENTS IN THERMAL DEBINDING OF MIM COMPACTS

Two-component binder model systems composed of the non-polar polymer p olypropylene and either non-polar paraffin wax (PW) or moderately pola r stearic acid (SA) as low molecular weight components (LMWC) have bee n chosen in order to study the achievable weight loss (removable mass) of LMWCs during conventional thermal debinding in the lower temperatu re regime. Stainless steel 316L served as the powder material If has b een found that the removable mass of SA is considerably lower than tha t of PW. This effect reflects the physical interaction of the low mole cular weight components with the basic polymer. The influence of the d ebinding temperature and the sample thickness on the removable mass is discussed. The phenomena of removable mass influences the burnout cyc le of powder injection moulded parts and attention has to be paid to t his effect when devising a conventional thermal debinding treatment fo r a given binder.