Keywords
coatings regeneration
dissolution
turbine blades
superalloys
IN-100
How to Cite
Abstract
Selected methods of removing diffusion alluminide coating used for protection of turbine blades were presented in the article. The chemical and electrochemical methods of coatings dissolution used in aerospace industry were described. Three selected removing agents were selected for experimental tests: hydrochloric acid in ethanol solution, sulphuric acid in water as well as mixture of orthophosphoric, acetic and nitride acids. The aluminide coating obtained on IN-100 nickel superalloy was used for tests. The conducted research showed that the mixture of orthophosphoric, acetic and nitride acids can dissolve outer-zone of aluminidce coating during 80 min dissolution process. The removing process takes place evenly on the whole surface of sample.
References
Rosenzweig M.A., Conner J.A., Bowden J.H.J.: Method of removing hot corrosion products from a diffusion aluminide coating, US patent nr 6, 174, 380 B1 (2001), http://www.google.com/patents/US6174380%5Cnhttp://patentimages.storage.googleapis.com/pdfs/US6174380.pdf.
Baldi A.L.: Process of stripping aluminide coating from cobalt and nickel base alloys, US patent nr 3, 622, 391 (1971).
Grisik J.J., Ellis A.J.: United States Patent, 3, 833, 414 (1974).
Lee J.W., Voehringer C.: Method of remanufacturing turbine vane clusters for gas turbine engines, US patent nr 4, 176, 433, (1979).
Gupta B.K., Grady R.W., Garcia A.F.: Repair method for tbc coated turbine components, US 2010/0126014 (2010).
Rosenzweig M.A., Conner J.A., Bowden J.H.J.: Method of removing hot corrosion products from a diffusion aluminide coating, US patent nr 6, 174, 380 B1 (2001).
Kool L.B., Ruud J.A.: Process for partial stripping of diffusion aluminide coatings from metal substrates and related compositions, US patent nr 6, 758, 914 B2 (2004).
Macdonald L.S., Sangeeta D., Rosenzweig M.A.: Method for removing an aluminide coating from a substrate, US patent nr 6, 494, 960 B1 (2002).
Sangeeta D., Macdonald L.S.: Method for removing an aluminide-containing material form a metal substrate, US patent nr 5, 976, 265 (1999).
Kool L.B., Ruud J.A.: Method for removing oxides and coatings from a substrate, US patent nr 6, 863, 738 B2 (2005).
Chen K.N., Ngiam S.T.: Method for renewing diffusion coatings on superalloy substrates, US patent nr 6, 355, 116 B1 (2002).
Lucas J.G.: Chemical stripping process, US patent nr 3, 607, 398 (1971).
Fisher R.E., Lada H.: Selective chemical milling of recast surfaces, US patent nr 4, 411, 730 (1982).
Fisher R.E., Lada H., Putnam V.M.: Method and composition for removing nickel aluminide coatings from nickel superalloys, US patent nr 4, 425, 185 (1984).
Wei B., Lipkin D.M., Macdonald L.S.: Electrochemical system and process for stripping metallic coatings, US patent nr 6, 352, 636 B1 (2002).
Updegrove K., Goodwater F., William F.: Electrochemical stripping of turbine blades, US patent nr 6, 165, 345 (2000).