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CO2 lasers application in ceramic coatings for thermal and chemical protection

Grant number: 13/08920-1
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): February 01, 2014
Effective date (End): July 26, 2015
Field of knowledge:Engineering - Aerospace Engineering
Principal researcher:Getúlio de Vasconcelos
Grantee:Viviane Teleginski Mazur
Home Institution: Instituto de Estudos Avançados (IEAv). Departamento de Ciência e Tecnologia Aeroespacial (DCTA). Ministério da Defesa (Brasil). São José dos Campos , SP, Brazil

Abstract

Aircraft and power plants turbine blades are subject to oxidation reactions, for operating in harsh environments at high temperatures and pressures. To avoid this effect ceramic coatings are applied over a metallic substrate. Yttria stabilized zirconia is one of the most employed ceramic material. Physical and chemical properties of metals and ceramics are widely divergent, so it is common the use of a bond-coat between them, providing better adhesion and gradual change in thermal expansion coefficient. This project aims to study laser surface treatment technologies of ceramic turbine blades. The laser surface texturing of the metallic substrates will be done by an Yb: fiber laser, in order to promote a better adhesion of the bond-coat. Further, the bond-coat layer will be deposited and irradiated by a CO2 laser intending to form a metallurgical bond with the substrate. Yttria stabilized zirconia will be deposited over the binder and will also be treated by a CO2 laser aiming microstructural control and close the surface pores. The influence of laser treatment on the coatings properties at all stages mentioned will be microstructural, mechanical and chemical analyzed by different characterization techniques. The thermal stability of the coatings will be evaluated using a defocused CO2 laser beam by the temperature monitoring on the ceramic surface region and on the metal substrate. (AU)