# US 2004/0069748 A1 · Electrochemical process for the simultaneous stripping of diverse coatings from a metal substrate

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2004/0069748 A1
- Document ID: US20040069748A1
- Status: Published application
- Kind: A1
- Application number: 10/268,337
- Filed: 2002-10-09
- Published: 2004-04-15
- Earliest claimed: 2002-10-09
- Assignees: United Technologies Corporation
- Inventors: Michael A. Kryzman; Mark Jaworowski
- Web page: https://patentgrep.com/patent/US20040069748A1

## CPC

- C25F 5/00: Electrolytic stripping of metallic layers or coatings
- C25F: PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR

## Abstract

An electrochemical process for simultaneously stripping diverse coatings from a metal substrate and, more particularly to the removal of MCrAlY and aluminide coatings from a base metal.

## Claims

### Claim 1

A process for the simultaneous removal of at least two diverse coatings from a metal substrate comprising the steps of:
providing an element comprising a metal substrate having at least two diverse coatings thereon;
immersing the element in an electrolyte; and
applying a potential across the electrolyte at a magnitude wherein the at least two coatings are dissolved and removed from the metal substrate.

### Claim 2 (depends on 1)

A process according to claim 1 wherein said electrolyte comprises an acid solution.

### Claim 3 (depends on 2)

A process according to claim 2 wherein the acid solution is selected from the group consisting of hydrochloric acid solution, nitric acid solution, sulfuric acid solution and mixtures thereof.

### Claim 4 (depends on 2)

A process according to claim 2 wherein the acid solution is a hydrochloric acid solution.

### Claim 5 (depends on 4)

A process according to claim 4 the electrolyte comprises 5 to 10 volume % solution of hydrochloric acid.

### Claim 6 (depends on 1)

A process according to claim 1 including agitating the electrolyte while applying the potential.

### Claim 7 (depends on 1)

A process according to claim 1 including carrying out the process under ambient conditions.

### Claim 8 (depends on 1)

A process according to claim 1 wherein the metal substrate is coated with MCrAlY on one surface (where M is selected from the group consisting of Ni, Co, and mixtures thereof) and aluminide on the other surface thereof.

### Claim 9 (depends on 1)

A process according to claim 1 wherein the metal substrate is a metal alloy selected from the group consisting of stainless steel alloys, nickel alloys, cobalt alloys, and nickel-cobalt alloys.

### Claim 10 (depends on 1)

A process according to claim 1 wherein the potential is greater than +50 mV and up to about +150 mV volts versus a Ag/AgCl reference electrode.