The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 21, 1976
Filed:
Jul. 30, 1970
Jean Berchtold, La Jolla, CA (US);
Eastman Kodak Company, Rochester, NY (US);
Abstract
A magnetic head assembly wherein the material of the pole tips or of the pole pieces comprises a hot-pressed sintered iron-silicon-aluminum alloy, the particles of such alloy preferably being provided with a nitride layer or coating prior to sintering for preventing or retarding grain growth during sintering and to provide increased electrical resistivity and hardness in the end product. The preferred hot-pressed sintered material is characterized by a substantially uniform grain size most preferably of between about 40 microns and 60 microns, a porosity of substantially less than one percent, a Vickers hardness greater than 600, and a resistivity of at least about 100 micro-Ohm-cm. A method of making such a sintered material preferably comprises heating an iron-silicon-aluminum alloy powder in an atmosphere of nitrogen to form a nitride layer thereon, blending 80% of such nitrided alloy powder with from about 10 to 20% of elemental iron, silicon and aluminum powders, without varying the composition from that desired in the final alloy, and heating the mixture to a sintering temperature while applying a pressure of about 1000 pounds per square inch.