Process for removing aluminum-silicon coatings from metallic structures, and related processes for preparing magnetic components
AssigneeGeneral Electric Company
InventorsPeter John Bonitatibus, Jr., Francis Johnson, Min Zou
Life of this patent
Estimating the term…
Abstract
A method for selectively removing an aluminum-silicon coating fired on a surface of a metallic structure is described. The method includes the step of contacting the coating with molten potassium hydroxide (KOH), under conditions sufficient to remove the coating without substantially affecting the metallic surface. Methods for preparing a magnetic component are also described. They involve masking pre-selected regions of the surface of the component, using an aluminum-silicon coating that is fired onto the surface, prior to a nitriding step. The coating is then removed according to the procedure outlined herein.
Claims20
A method for selectively removing an aluminum-silicon coating tired on a surface of a metallic structure, comprising the step of contacting the coating with molten potassium hydroxide (KOH), under conditions sufficient to remove the coating without substantially affecting the metallic surface, wherein the molten potassium hydroxide contacts the coating at a temperature in the range of about 270° C. to about 280° C.
A method of preparing a magnetic component, comprising:
- masking pre-selected sections of a surface portion of the component, using a nitrogen masking material that comprises a fired aluminum-silicon coating, to form a masked region in the component;
- b) heat-treating the component in a nitrogen-rich atmosphere at a temperature greater than about 900° C., to form intermixed first and second regions in the magnetic alloy;
- wherein
- the first region comprises a magnetic phase;
- the second region comprises a non-magnetic phase;
- the second region comprises greater than 0.1% nitrogen;
- and then
- c) selectively removing the nitrogen masking material, by contacting the material with molten potassium hydroxide, under conditions sufficient to remove the masking material without substantially affecting the component.
A method for selectively removing an aluminum silicon coating fired on a surface of a metallic structure, comprising the step of contacting the coating, with molten cesium hydroxide (CsoH) or a combination of molten potassium hydroxide (KOH) and molten CsOH, under conditions sufficient to remove the coating without substantially affecting the metallic surface.
Dependencies are inferred from the claim text.