Insulative coating for electrical steels
US3996073A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 5, 1975 |
| Grant date | Dec 7, 1976 |
| Priority date | — |
| Expiry date | Nov 5, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F1/14783
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Insulative coatings for electrical steels and methods of making them. The coatings are hard, glassy and smooth in nature, are easily cured and improve the magnetic characteristics of the electrical steels. The coatings are produced by applying to an electrical steel an aluminum-magnesium-phosphate solution containing Al.sup.+.sup.+.sup.+, Mg.sup.+.sup.+ and H.sub.2 PO.sub.4.sup.- in a specified relative relationship and from 0 to 60% by weight colloidal silica on a water-free basis. The solutions contain at least 45% by weight water. Chromic anhydride (CrO.sub.3) may be added to the coating solutions to improve wettability of the solutions, moisture resistance of the resulting coatings and interlaminar resistivity after stress relief anneal. An electrical steel coated with a solution of the present invention is thereafter subjected to a heat treatment to cure the insulative coating thereon.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.