United Technologies Corporation

Glenn T Janowsky

Mark R Jaworowski

Michael A Kryzman

Curtis Heath Riewe

Louis L Packer

Charles H Weston

Christopher C Shovlin

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.

Feedback controlled airfoil stripping system with integrated water management and acid recycling system

A method of fabrication and inspection includes depositing a coating and determining at least one physical property of the coating using eddy current techniques. In a detailed embodiment an abradable coating having a metal volume fraction in the range of from 0.3 to 0.5 is applied to an inner circumference of a stator for a gas turbine engine compressor. The eddy current probe is positioned by a manipulator. A distance separating the probe and a surface of the coating is measured using a frequency above one megahertz (MHz). The thickness of the coating is measured by determining the rolloff frequency for the coating's complex impedance. The coating density is determined by its complex impedance at a characteristic frequency below four MHz. The density can be used as an indication of the performance of the coating with respect to abradability and the erosion resistance. The measurements may also be applied as a post-process quality control technique.

Method for fabricating and inspecting coatings

This invention relates to a method for making porous metal plasma sprayed abradable seals. Radiation transmission techniques are utilized to determine the as-sprayed density of a deposit containing metal and polymer powder particles. Based on the measuring density, a mathematical prediction is made of what the surface hardness of the sprayed deposit will be after it has been machined and then heated to remove the polymer powder particles. If the predicted hardness is outside of the desired range, changes are made in the plasma spray parameters.

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Coventry, CT, United States of America

Glenn T Janowsky