Richard N Gardner

US Patent:

43271561, Apr 27, 1982

Filed:

May 12, 1980

Appl. No.:

6/148809

Inventors:

Kenneth R. Dillon - White Bear Lake MN
Richard N. Gardner - Stillwater MN

Assignee:

Minnesota Mining and Manufacturing Company - St. Paul MN

International Classification:

B22F 300
C22C 105

US Classification:

428568

Abstract:

A precision molded article, such as a die cavity, is made by combining granules of a refractory and granules of a first metal or alloy which has a homogeneous crystalline appearance at a temperature below its melting point and has a lower Rockwell Hardness than the refractory, mixing the granules with a heat fugitive organic binder, molding the granule-binder mixture into a green molded preform, thermally degrading and removing essentially all the binder to form a skeletal preform, and infiltrating the preform with a second metal or alloy which will wet the first metal or alloy and has a lower Rockwell Hardness than the first metal or alloy, thereby forming a molded article having refractory granules fully enveloped within a single skeleton of the first metal or alloy, the refractory granules and skeleton of first metal being surrounded by layers or matrices of softer metals.