United Technologies Corporation

Curtis Heath Riewe

Mark R Jaworowski

Alan David Cetel

Brian S Tryon

Joseph Parkos, Jr

Michael A Kryzman

Thomas M Morin

Glenn T Janowsky

Dwayne A Braithwaite

Christopher C Shovlin

A method of stripping gamma/gamma prime polycrystalline alloy bond coats from single crystal gamma/gamma prime nickel based superalloys, including the steps of grit blasting followed by the use of hydrochloric acid solutions, followed by rinsing. The cycle may be repeated several times, with visual inspection between cycles.

Method for stripping gamma-gamma prime coating from gamma-gamma prime alloy

A process for forming a coated substrate comprises providing a nickel base alloy substrate, depositing a chromium coating onto the nickel base alloy substrate and diffusing chromium from said coating into the substrate, applying a MCrAlY coating onto the nickel base alloy substrate and heat treating the substrate with the deposited chromium and the MCrAlY coating so that chromium diffuses into an outer region of the substrate. Further, in accordance with the present invention, a strip process for removing a coating from a substrate broadly comprises the steps of providing a nickel base alloy substrate having chromium diffused into an outer region and a MCrAlY coating deposited over the substrate with the diffused chromium and removing the MCrAlY coating by immersing the nickel base alloy substrate in an acid solution containing a sulfuric acid-hydrochloric acid mixture in water.

Strip process for superalloys

The present invention relates to a control loop to be used in a system for stripping a coating from a part. The control loop comprises an electrometer for measuring a potential between the part and a reference electrode and generating a voltage output signal, an operational amplifier for comparing the voltage output signal to a set point voltage and for producing an output signal to be used to reduce the difference between the voltage output signal and the set point voltage, and a high current power transistors for supplying a current to the part.

Electrochemical stripping using single loop control

The present invention relates to a feedback controlled stripping system with integrated water management and acid recycling system. The system comprises a stripping tank containing an electrolyte bath stripping solution for removing a coating from at least one workpiece immersed in the stripping solution while a controlled absolute electrical potential is maintained on the at least one workpiece with respect to a reference electrode also immersed in the stripping solution, a rinse tank for rinsing the workpiece(s) after removal of the workpiece(s) from the stripping tank, and a distillation unit for receiving electrolyte containing dissolved metals from the stripping tank, for purifying the electrolyte received from the stripping tank, and for returning the purified electrolyte to the stripping tank. In a preferred embodiment, the stripping tank, the rinse tank, and the distillation unit are mounted to a skid. The system further includes a control module. A process for using the system to remove a coating from a workpiece is also described.

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Manchester, CT, United States of America

Curtis Heath Riewe