| abstract |
A new class of binders is provided for admixture with metallic or ceramic powders for sintering into shaped objects of uniform density by utilizing injection molding, extrusion, or other mechanical shaping techniques. The novel binders are solid polymer solutions containing a major fraction of a low molecular weight solid chemical as solvent and a minor fraction of at least one high molecular weight solid polymer as solute substantially dissolved there-in. The solid polymer solution binders when molten can be uniformly mixed with known metallic or ceramic powders into a readily flowable mixture which when solidified, can retain a given shape. Then, the binder can be eliminated by an advantageous two-stage "debinding" procedure involving selective extraction of the solid chemical while the solid chemical stays rigid and the polymer fraction undisturbed, e.g. by solvent leaching or sublimation, followed by thermal removal of the polymer to obtain a shaped part ready for sintering. A coupling agent, a plasticizer or other additive may be included. |