Gm Global Technolgoy Operations, Inc.

David L Clingman

Kenneth R Cross

John R Cavanagh

Berton Schechter

Lawrence E Brown

Michael J Barber

John F Kroemer

An abrasive system and a processing procedure is provided which permits the direct installation of a thick abrasive blade tip cap onto a cast turbine rotor blade during a heating schedule which requires two furnace operations. The composition of the abrasive blade tip cap advantageously utilizes the high temperature performance capabilities of equiaxed or single crystal rotor blade alloys without significantly affecting their mechanical properties as a consequence of the processing necessary to permanently bond the abrasive blade tip cap to the rotor blade. A semi-rigid mat consisting of the preferred abrasive composition is first consolidated in a first vacuum furnace operation. Blade tip cap preforms are then cut from the mat and positioned on the tip of the rotor blade. The preform and rotor blade are then heated in a vacuum furnace according to a temperature schedule entailing heating rates, holding temperatures and durations which are sufficient to bond the preform to the rotor blade. The rotor blade is then rapidly cooled in the vacuum furnace to retain the microstructure and mechanical properties of the rotor blade.

Method for bonding abrasive blade tips to the tip of a gas turbine blade

An abrasive system and a processing procedure is provided which permits the direct installation of a thick abrasive blade tip cap onto a cast single crystal turbine rotor blade during a single heating schedule requiring only one furnace operation. The composition of the abrasive blade tip cap advantageously utilizes the high temperature performance capabilities of the single crystal alloy without significantly affecting its mechanical properties as a consequence of the processing necessary to permanently bond the abrasive blade tip cap to the rotor blade. A semi-rigid blade tip cap preform is first formed and positioned on the tip of the rotor blade. The preform and rotor blade are then heated in a vacuum furnace according to a temperature schedule entailing heating rates, holding temperatures and durations which are sufficient to bond and consolidate the preform. The rotor blade is then rapidly cooled in the vacuum furnace to retain the single crystal structure of the rotor blade.

Abrasive blade tips for cast single crystal gas turbine blades

A method of applying a thermal barrier coat on an exposed side of a porous metal laminate which method includes the steps of spreading on the laminate an air-curable maskant to force maskant into the perforations in the exposed side, removing excess maskant from the exposed side so that maskant plugs remain in the perforations with tops generally coplanar with the exposed side, allowing the maskant to cure, directing sprays of bond coat and top coat incompatible with the maskant at the exposed side of the porous laminate to deposit a thermal barrier coat thereon but not on the maskant plugs, and removing the maskant plugs by thermal and chemical treatment or by chemical treatment alone.

Porous laminate surface coating method

An improved method for coating a porous metal laminated structure having air flow holes on the coated side of the structure including in part, the steps of roughening an exposed surface of the porous laminated material and thereafter spraying a bond layer on the roughened surface at an angle selected to coat it with a thin bond coat layer while depositing only a limited amount of the bond coat material internally of the air flow holes and thereafter spray coating the bond coated surface with a top ceramic coat of heat resistant composition and characterized by requiring a bond coat for adherence to the porous metal laminated material and wherein the top ceramic coat spray angle is inclined opposite to that of the spray angle of deposition of the bond coat material to prevent deposition of the top coat on bond material internally of the air flow holes so as to prevent bonding of the ceramic top coat in the air flow holes thereby to minimize restriction of flow through the air flow hole in the exposed surface of the porous metal laminate.

Method for coating porous metal structure

An abradable ceramic seal coating on at least one of a pair of members having relative rotational movement, the coating being formed of stabilized zirconia which is codeposited with a thermally decomposable organic powder, the codeposited layer being heated to decompose the organic filler and produce a porous coating of from about 20 to about 33% voids.

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Carmel, IN, United States of America

David L Clingman