Effect of TBC on oxidation behaviour of gamma-TiAl based alloy

• Autorzy: Moskal G.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The purpose of the research was identification of the influence of TBC coating system on oxidation resistance of TiAl based alloy during oxidation at temperature of 900 and 950 degrees centigrade for 500 h and 200 h respectively. Design/methodology/approach: The APS technique was used to modify and improvement of oxidation resistance of TiAl intermetallic alloy. As a bond coat the NiCrAlY overlay coating was applied. The bond-coat provided a good bonding strength between matrix and ceramic top coat. The research allowed the identification of microstructural changes that take place between top coat and bond coat and bond coat and substrate. The examinations were conducted on specimens after 200 h and 500 h of exposition at 950 and 900 degrees centigrade. Findings: It was found that the surface conditions of basic alloy is electively protected by used type of ceramic coating. The basic alloy exhibited poor oxidation resistance at this range of temperature due to formation of mixed Al2O3 + TiO2 scale which is easily spalled off. A ceramic top coat together with bond coat can be effectively coated on the surface of TiAl basic alloy by APS method. Oxidation test both at 900 and 950 degrees centigrade showed that oxidation resistance of APS coated 48-2-2 alloy was improved. Research limitations/implications: Application of TBC remarkably improve the oxidation resistance of TiAl basic alloy due to lowering temperature of the substrate surface and due to formation of dense alumina sublayer (TGO) on the top surface of bond coat which can prevent diffusion processes of titanium and oxygen. Practical implications: The results obtained allow the determination of the degree of life-time lost of the TBC system used as protection for titanium aluminides alloys. Originality/value: The results obtained are valuable contribution to the development of new type of TBC for TiAl alloys. They enable the identification of the degradation mechanisms in YSZ/MCrAlY/substrate system.

Słowa kluczowe

EN

metallic alloys; thin coatings; thick coatings; TBC; degradation; oxidation

PL

stopy metaliczne; cienkie powłoki; powłoki grube; TBC; powłoki TBC; powłokowe bariery cieplne; degradacja; utlenianie

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2007
• Tom: Vol. 22, nr 2
• Strony: 31--34
• Opis fizyczny: Bibliogr. 14 poz., fot., rys., tab.

Twórcy

autor

Moskal G.

• Department of Materials Science, Silesian University of Technology, ul. Krasińskiego 8, 40-019 Katowice, Poland,

Bibliografia

• [1] H. Clemens, H. Kestler, Processing and Applications of Intermetallic gamma-TiAl-Based Alloy, Advanced Engineering Materials 2/9 (2000) 551-570.
• [2] M.T. Jovanovic, B. Dimcic, I. Bobic, S. Zee, V. Maksimovic, Microstructure and mechanical properties of precision cast TiAl turbocharger wheel, Journal of Materials Processing Technology 167 (2005) 14-21.
• [3] J.L. Smialek, J.A. Nesbitt, W.J. Brindley, M.P. Brady, J. Doychak, Service limitations for oxidation resistance intermetallic compounds, Proceedings of the MRS Symposium High Temperature Ordered Intermetallic Alloys VI, 1273-1284.
• [4] M. Góral, G. Moskal, L. Swadźba, The influence of Si on structure of aluminide coatings deposited on TiAl alloy, Journal of Achievements in Materials and Manufacturing Engineering 18 (2006) 463-466.
• [5] M. Góral, G. Moskal, L. Swadźba, The influence of Si on oxidation resistance of aluminide coatings on TiAl alloy, Journal of Achievements in Materials and Manufacturing Engineering 18 (2006) 459-462.
• [6] Ashok Kumar Ray, Characterization of bond coat in a thermal barrier coated superalloy used in combustor liners of aero engines, Materials Characterization 57 (2006) 199-209.
• [7] D. Stover, C. Funke, Directions of the development of thermal barrier coatings in energy applications, Journal of Materials Processing Technology 92-93 (1999) 195-202.
• [8] L. Swadźba, G. Moskal, B. Mendala, T. Gancarczyk, Characterization of air plasma sprayed TBC coating during isothermal oxidation at 1100°C, Journal of Achievements in Materials and Manufacturing Engineering 21 (2007) 81-84.
• [9] G. Moskal, The porosity assessment of thermal barrier coatings obtained by APS method, Journal of Achievements in Materials and Manufacturing Engineering 20 (2007) 483-486.
• [10] M. Fröhlich, R. Braun, C. Leyens, Oxidation resistant coatings in combination with thermal barrier coatings on –gamma-TiAl alloys for high temperature applications, Surface and Coatings Technology 201 (2006) 3911-3917.
• [11] I.C. Hsu, S.K. Wu, Oxidation improvement of Ti-48Al-2Cr-2Nb intermetallic in air by plasma sparyed Zr02-Ni-4,5%wt.Al coatings, Surface and Coatings Technology 90 (1997) 6-13.
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