Gear surface treatment procedure
AssigneeGM Global Technology Operations LLC
InventorsLeonid Lev, Michael Lukitsch, Yang-Tse Cheng, Anita Weiner, Robert Paluch
Life of this patent
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Abstract
A method of surface treating heat treated members to remove oxide scale. The heat treated members are subjected to a staged series of discrete chemical and physical cleaning steps yielding a substantially scale-free surface readily adaptable for subsequent application of protective coatings.
Claims19
A method of treating a heat hardened alloy gear member at least partially covered with an oxide scale for acceptance of a protective coating, the method comprising the steps of:
- (a) subjecting the alloy gear member to a chemical treatment comprising cathodic cleaning followed by acid etching to soften and at least partially dissolve the scale;
- (b) vapor blasting the alloy gear member with a suspension of abrasive particles in a fluid suspension following the chemical treatment in step “a”;
- (c) cleaning the alloy gear member after vapor blasting to remove adhered particulate residue;
- and
- (d) subjecting the alloy gear member to ion etching in a vacuum chamber following step “c” to substantially remove any remaining oxide layer.
A method of treating a heat hardened alloy gear member at least partially covered with an oxide scale for acceptance of a protective coating, the method comprising the steps of:
- (a) subjecting the alloy gear member to a chemical treatment comprising the steps of soaking the alloy gear member in an alkaline solution, followed by cathodic cleaning of the alloy gear member, followed by acid etching of the alloy gear member to soften and at least partially dissolve the scale;
- (b) vapor blasting the alloy gear member with a suspension of abrasive particles in a fluid suspension following the chemical treatment in step “a”, wherein the particles used in vapor blasting are softer than the alloy material forming the alloy gear member;
- (c) cleaning the alloy gear member after vapor blasting to remove adhered particulate residue;
- and
- (d) subjecting the alloy gear member to ion etching in a vacuum chamber following step “c” to substantially remove any remaining oxide layer, wherein the ion etching is carried out in a plasma ignited in the vacuum chamber with chromium ions added to the plasma.
A method of treating a heat hardened alloy gear member at least partially covered with an oxide scale for acceptance of a protective coating, the method comprising the steps of:
- (a) subjecting the alloy gear member to a chemical treatment comprising the steps of soaking the alloy gear member in an alkaline solution, followed by cathodic cleaning of the alloy gear member in an alkaline solution, followed by acid etching of the alloy gear member to soften and at least partially dissolve the scale;
- (b) vapor blasting the alloy gear member with a suspension of pumice particles in a fluid suspension following the chemical treatment in step “a”;
- (c) cleaning the alloy gear member after vapor blasting to remove adhered particulate residue;
- and
- (d) subjecting the alloy gear member to ion etching in a vacuum chamber following step “c” to substantially remove any remaining oxide layer, wherein the ion etching is carried out in a plasma ignited in the vacuum chamber with chromium ions added to the plasma wherein a negative accelerating voltage is applied to the alloy gear member during ion etching.
Dependencies are inferred from the claim text.