Gte Laboratories Incorporated

Gte Products Corporation

Kenneth W French

Gautam Bandyopadhyay

Jeffrey T Neil

Alfred Piorkow

Leslie J Bowen

J Thomas Smith

Sheldon I Lieberman

Kenneth H Shaner

Robert C Kocher

Larry L Turnbaugh

A method of producing crack free ceramic parts having large cross-sections is disclosed. An initial mixture of ceramic powder containing a binder and from 0.1 v/o to 10 v/o of whiskers or fibers which are made of carbon, graphite or high temperature melting or decomposition point organic polymers. The mixture is either injection molded or slip cast to form a shaped article. The shaped article is heated in a nitrogen atmosphere to a temperature of 450.degree. C. and then in an atmosphere of air at a temperature of 450.degree. C. to 600.degree. C. to completely remove the binder. The resulting binderless shaped article is then heated at 800.degree. C. for a period of time sufficient to completely remove the whiskers or fibers from the shaped articles. The article is then encapsulated in glass and hot isostatically pressed at a pressure of 30,000 psi to densify the article to approximately 99% of theoretical. The resulting article has a complex geometry and a large cross-section but without detrimental cracks.

Method of making large cross section injection molded or slip cast

A method for fabricating large, greater than one centimeter cross section, high density silicon nitride by injection molding process has been developed. The method requires use of a controlled starting powder, a novel binder removal process, a prefiring step followed by isopressing and conventional sintering.

Method for fabricating large cross section injection molded ceramic

A method for fabricating injection molded ceramic shapes suitable for densification by sintering or hot isostatic pressing has been developed. The method is applicable to ceramic articles of large, complex cross sections, greater than one centimeter, which are generally prone to external cracking during binder removal. The method requires use of a controlled starting powder, and a novel binder removal process to obtain an externally crack-free article.

Method for injection molding and removing binder from large cross

Apparatus for automatically measuring aperture size of apertured material includes a means for supporting and transporting the apertured material and a light source providing a light beam directed for passage through the apertured material to a light detector and is characterized by a comparator mask of alternate light transparent and opaque sectors of a given dimension and means for overlaying the apertured material with the comparator mask to provide a given length of light transparent slot and responsive to signals representing light transmitted through the given length of slot for deriving a signal representing the width of the slots of the slotted material. Also, a process for automatically measuring aperture size includes the steps of overlaying the slotted material with the comparator mask and utilizing a signal from the light detector representing light transmission of the slots of a given length to derive a signal representative of the slot width.

Apparatus and process for automatically measuring aperture size of

A composition for injection molding a sinterable material such as silicon nitride. This composition includes a binder system which imparts a greater flexibility to the, as molded, green body. The binder-system contains a major component of paraffin wax, a minor component of epoxy resin, and a surfactant.

Composition for injection molding

A comparator mask for use in apparatus for measuring aperture size of apertured material includes a light transparent section and at least one other section having alternate light transparent and opaque sectors whereby the comparator mask overlays the apertured material to provide an area of light transmission utilized to determine the dimensions of the aperture of the apertured material.

Growing community of inventors

Merrimack, NH, United States of America

Kenneth W French