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:
Mar. 09, 1993
Filed:
Apr. 12, 1991
Wade S Wright, Fairfield, OH (US);
Robin A Murphy, Franklin, OH (US);
Armco, Inc., Middletown, OH (US);
Abstract
Decarburized grain oriented silicon steel is provided with an annealing separator which forms a glass film after the final high temperature anneal. The magnesia used as the annealing separator has a total chlorine level of 0.01 to 0.20% by weight based on the weight of magnesia with at least 0.01% metal chloride selected from the group of Mg, Ca, Na and K. The chloride addition acts to seal the coating surface during the final anneal to control diffusion and stabilize the secondary grain growth. The glass film which forms during the anneal may be laser scribed for domain refinement without coating damage. The magnesia may also contain additions of phosphates, TiO.sub.2, SiO.sub.2, Cr and B. The temperature of the magnesia is maintained below 25.degree. C. to control hydration and eliminate the need for other additives in the magnesia slurry to control hydration.