Manufacture of complex shaped Cr.sub.3 C.sub.2 /Al.sub.2 O.sub.3 components by injection molding technique

Abstract

The purpose of this invention is to manufacture complex shaped Cr.sub.3 C.sub.2 /Al.sub.2 O.sub.3 components efficiently with effective cost. Chromium carbide, which is quite chemically inert at elevated temperature, is added into an alumina matrix for toughening purposes. Chromium carbide and alumina ceramic powders are mixed with binders to form a solidified suspension. The suspension is then crushed, heated, and injected into green products. Controlled solvent and thermal debinding processes are followed before performing pressureless sintering. Samples are sintered in pre-treated argon gas with minimum oxygen partial pressure, or in vacuum for controlling the phase stability and microstructure for tailoring mechanical properties. The processing parameters for injection molding, the composition design of binders and ceramic composites, and the techniques for controlling the phase transformation of chromium carbide are developed. A near-net shape complex component with minimum after machining can be manufactured. The injection molding and pressureless sintering process make the mass production possible. Optimized properties of 97.8% in the theoretical density, 500 Mpa in strength, and 5.85 MPam.sup.1/2, are obtained. These properties are greater, in comparison, than the properties of conventional alumina ceramics.

Dependencies are inferred from the claim text.