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Method of making active magnetic refrigerant, colossal magnetostriction and giant magnetoresistive materials based on Gd-Si-Ge alloys

United States Patent

July 8, 2003
View the Complete Patent at the US Patent & Trademark Office
Ames Laboratory - Visit the Iowa State University Research Foundation - Office of Intellectual Property & Technology Transfer Website
Production of Giant magnetocaloric Substances Using Commercially Available Raw Materials
Cost Effective Production of Giant Magneto-Caloric Materials
Method of making an active magnetic refrigerant represented by Gd.sub.5 (Si.sub.x Ge.sub.1-x).sub.4 alloy for 0.ltoreq.x.ltoreq.1.0 comprising placing amounts of the commercially pure Gd, Si, and Ge charge components in a crucible, heating the charge contents under subambient pressure to a melting temperature of the alloy for a time sufficient to homogenize the alloy and oxidize carbon with oxygen present in the Gd charge component to reduce carbon, rapidly solidifying the alloy in the crucible, and heat treating the solidified alloy at a temperature below the melting temperature for a time effective to homogenize a microstructure of the solidified material, and then cooling sufficiently fast to prevent the eutectoid decomposition and improve magnetocaloric and/or the magnetostrictive and/or the magnetoresistive properties thereof.
Gschneidner, Jr.; Karl A. (Ames, IA), Pecharsky; Alexandra O. (Ames, IA), Pecharsky; Vitalij K. (Ames, IA)
Iowa State University Research Foundation, Inc. (Ames, IA)
09/ 793,822
February 23, 2001
CONTRACTUAL ORIGIN OF INVENTION The United States Government has rights in this invention pursuant to Contract No. W-7405-ENG-82 between the U.S. Department of Energy and Iowa State University, Ames, Iowa, which contract grants to the Iowa State University Research Foundation, Inc. the right to apply for this patent.