Abstract A thin, compliant seal for the regenerator of a gas turbine engine or the like and a method of making same. The seal is comprised of a plurality of individual seal elements that are interrelated with each other at their ends to preclude leakage. Two embodiments of end relationships are shown. In one embodiment two of the seal elements have interengaging portions that provide a loose connection between the elements. In the other embodiment, each of the seal ends carries a locating portion that coacts with means on the housing of the regenerator for providing a loose interrelationship between the seal ends. The end interrelationship of the seal elements in each embodiment permits relatively free movement of the seal elements under the influence of thermal expansion. This precludes warping of the seal as would occur if the seal were constructed from a single piece or if the seal was formed from pieces that were rigidly connected to each other. Each of the seal elements includes a first relatively thin, compliant part that is provided with a wear resistant coating that engages a rotating element. The coating is applied to a lightly oxidized surface of a relatively thin substrate which substrate is unstressed to reduce warpage. Cantilevered springs form another piece of each element. These cantilevered springs sealingly engage a static mating surface of the regenerator and resiliently bias the coated surface first piece into sealing engagement with the rotating element. The coating, as has been noted, is applied to an oxidized surface of the first part. In a preferred embodiment the coating is applied after the cantilevered spring is assembled to the first part. This subassembly is then held in a fixture and is preheated. A relatively thin transition layer of coating material is applied to the oxidized surface. The transition coating is formed from a material that will have an exothermic reaction with the oxidized surface. The final, wear resistant coating is then applied to the transition coating while maintaining the temperature and preventing excessive heating and, accordingly, warpage. The use of a thin seal and relatively thin coatings insures compliance of the seal with the mating surface of the rotating element.
THE METHOD OF APPLYING A WARD RESISTANT COATING TO A METAL SUBSTRATE FOR FORMING A COMPLIANT SEAL COMPRISING THE STEPS OF FORMING A METAL OXIDE LAYER ON THE PORTION OF THE SUBSTRATE TO BE COATED, DEPOSITING A TRANSTION COATING OF NICKEL ALUMINIDE ON THE OXIDIZED SURFACE, THE TRANSITION COATING OF NICKEL ALUMINIDE BEING CAPABLE OF EXOTHERMICALLY REACTING WITH THE METAL OXIDE LAYER TO FORM AN EFFECTIVE SURFACE BOND, EXOTHERMICALLY REACTING THE NICKEL ALUMINIDE TRANSITION COATING WITH THE METAL OXIDE LAYER AND DEPOSITING A WEAR RESISTANT METAL OXIDE COATING ON THE TRANSITION COATING.
Claim 2
Independent Claim
92 words
THE METHOD OF APPLYING A WARD RESISTANT COATING TO A METAL SUBSTRATE FOR FORMING A COMPLIANT SEAL COMPRISING THE STEPS OF FORMING A METAL OXIDE LAYER ON THE PORTION OF THE SUBSTRATE TO BE COATED, DEPOSITING A TRANSTION COATING OF NICKEL ALUMINIDE ON THE OXIDIZED SURFACE, THE TRANSITION COATING OF NICKEL ALUMINIDE BEING CAPABLE OF EXOTHERMICALLY REACTING WITH THE METAL OXIDE LAYER TO FORM AN EFFECTIVE SURFACE BOND, EXOTHERMICALLY REACTING THE NICKEL ALUMINIDE TRANSITION COATING WITH THE METAL OXIDE LAYER AND DEPOSITING A WEAR RESISTANT METAL OXIDE COATING ON THE TRANSITION COATING.
Claim 3
Dependent Claim
30 words
The method of applying a wear resistant coating as set forth in claim 1 further including the step of preheating the substrate prior to depositing of the transition coating thereon.
Claim 4
Dependent Claim
41 words
The method of applying a wear resistant coating as set forth in claim 2 further including the step of maintaining the temperature of the substrate within a predetermined range during the exothermic reaction of the transition coating with the oxidized surface.
Claim 5
Dependent Claim
29 words
The method of applying a wear resistant coating as set forth in claim 1 wherein the transition coating and wear resistant coatings are deposited by a flame spray technique.
Claim 6
Dependent Claim
30 words
The method of applying a wear resistant coating as set forth in claim 4 further including the step of preheating the substrate prior to depositing of the transition coating thereon.
Claim 7
Dependent Claim
31 words
The method of applying a wear resistant coating as set forth in claim 5 wherein the substrate is preheated to a temperature in the range of 200 to 300 degrees fahrenheit.
Claim 8
Dependent Claim
41 words
The method of applying a wear resistant coating as set forth in claim 6 further including the step of maintaining the temperature of the substrate within a predetermined range during the exothermic reaction of the transition coating with the oxidized surface.
Claim 9
Dependent Claim
44 words
The method of applying a wear resistant coating as set forth in claim 1 further including the step of affixing a cantilevered spring to the substrate prior to the coating thereof and holding the assembled spring and substrate against movement during the coating process.
Claim 10
Dependent Claim
43 words
The method of applying a wear resistant coating as set forth in claim 8 wherein the wear resistant coating is applied to the substrate to a thickness in the range of one to one and one half times the thickness of the substrate.