Howmet Research Corporation

C-Max Technology, Inc.

Xi Yang

Boyd A Mueller

Ronald James Keller

A method of making a ceramic shell mold comprises repeatedly coating a fugitive pattern of an article to be cast with a ceramic slurry layer and applying on the ceramic slurry layer a refractory stucco to form a plurality of ceramic slurry layers and stucco layers on the pattern wherein at least one of the stucco layers is formed by applying discontinuous stucco fiber bundles held together in the bundles by a fugitive binder, which is removed during subsequent firing of the shell mold at elevated temperature.

Reinforced shell mold and method

A method of forming a ceramic investment shell mold about a fugitive wax pattern of an article comprises coating the pattern with ceramic slurry, applying a ceramic particulate material heated above ambient temperature to the slurry layer, drying the ceramic slurry layer with ceramic particulates thereon, and repeating said coating, applying and drying steps to build up a shell mold on the pattern. The ceramic slurry with ceramic particulates thereon is dried initially dried for a time using relatively low humidity flowing air at an air temperature above about 80 degrees F. and then subsequently for a time using relatively low humidity flowing air at an air temperature not exceeding about 80 degrees F. Ceramic investment shell molds can be built-up in times typically less than 10 hours by practice of the invention with substantially reduced incidence of shell mold cracking during the shell mold building process and subsequent pattern removal operation.

Method of making investment casting molds

A method of making a ceramic shell mold comprises repeatedly coating a fugitive pattern of an article to be cast with a ceramic slurry layer and applying on the ceramic slurry layer a refractory stucco to form a plurality of ceramic slurry layers and stucco layers on the pattern wherein at least one of the stucco layers is formed by applying discontinuous stucco fibers followed by applying a granular stucco particles on the discontinuous stucco fibers.

The present invention provides a process for producing alumina matrix carbide and boride reinforced ceramic composites wherein for any particular composite, the relative density is about 97% or more of the theoretical density. The composites are prepared in a container wherein the interior surfaces of the container are graphite and have a protective coating consisting of a first layer comprising silicon carbide and boron carbide with a binder and a second layer comprising silicon carbide particles, wherein the protective coating prevents carbon bleed-through and the protective coating maintains a boride-containing equilibrium atmosphere during the process. The present invention further provides an alumina-based ceramic composite which comprises a metal carbide preferably selected from the group consisting of silicon carbide, titanium carbide and zirconium carbide, and mixtures thereof, and a boride preferably selected from the group consisting of boron carbide, titanium boride, or zirconium boride, and mixtures thereof. Finally, the present invention provides a protective coating for a surface comprising a first layer of a silicon carbide and a boron carbide in a binder and a second layer comprising a silicon carbide wherein the protective coating is able to withstand repeated exposure to high temperature.

Growing community of inventors

Muskegon, MI, United States of America

Xi Yang