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:
Aug. 20, 1991
Filed:
Sep. 10, 1990
Applicant:
Inventors:
Assignee:
NGK Insulators, Ltd., , JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B23K / ;
U.S. Cl.
CPC ...
156643 ; 156656 ; 21912168 ; 21912169 ; 252 795 ;
Abstract
A composite core for magnetic head composed of ferrite and Sendust, in which a difference between a track width of ferrite track and a track width of Sendust track is so small can be obtained by subjecting a gapped bar composed of ferrite and Sendust to a laser-induced etching in an alkali metal hydroxide aqueous solution into which additives for generating aluminate ion in the aqueous solution.