Process for injection molding sinterable carbide ceramic materials

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to ceramic compositions that may be injection molded and subsequently sintered, and to the process of producing a dense sintered body or article utilizing such compositions.
For the purpose of clarity, the detailed description is divided into two main sections.
One section with appropriate subsections relates to components of the composition.
The second section and appropriate subsections relate to the steps in the process utilized to produce a sintered product that has been injection molded.
I.
COMPOSITION COMPONENTS A.
Ceramic Material The ceramic material comprises at least about 65 percent and usually from about 70 to about 86 percent by weight of the composition.
A range of from about 72 to about 84 percent by weight is eminently useful, and, within this range, from about 76 to about 80 percent by weight has been found to be especially adapted to use.
Generally, loadings of less than about 70 percent by weight do not produce a final sintered product of the desired density, and loadings greater than about 86 percent by weight are injection molded only with difficulty.
The ceramic material utilized in the present invention is preferably utilized in finely divided form.
The preferred material has an average size from about 0.
10 to about 2.
00 microns, with a maximum size of about 5.
00 microns.
Although size is a critical parameter, surface areas is equally of relevant consideration in determining the suitable material.
Accordingly, the preferred silicon carbide particles as used in the present composition have a surface area of from about 1 to about 100 m.
sup.
2 /g.
Within this range, it is more preferred that the surface area of particles range between about 5 and about 20 m.
sup.
2 /g.
Particles with a surface area in this latter range have been found eminently useful in producing the compositions of the present invention.
Silicon carbide is a preferred ceramic material.
The silicon carbide may be either alpha or beta phase or may be amorphous