High temperature corrosion of Ti-46Al-7Nb-0.7Cr-0.1Si-0.2Ni intermetalics–based alloys in N2-O2-SO2 environments

• Autorzy: Małecka J. , Grzesik W.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The reason for this research is to test the intermetalic alloy with improved oxidation and sulfidation resistance to air and a N2-O2-SO2 gas mixture at temperatures higher than 900 şC, typical for working conditions of highly loaded parts of gas turbine. Design/methodology/approach: The objectives were achieved using several techniques including conventional metallography, SEM, BSE, EDX and precision measurements of mass loss. The oxides scales and their effects were investigated and compared for two test temperatures, i.e. 900 şC and 950 şC. Findings: This investigation confirms that oxidation in 9%O2+0.3%SO2+N2 atmosphere causes an increase in the rate of oxidation in comparison to the pure oxidation in air. The main conclusion is that combined oxidation and sulfidation at temperature between 900 şC and 950 şC results in the formation of specific phases at the product-substrate and product-oxide boundaries. Research limitations/implications: The basic limitations concern alloys with different chemical composition, especially with different percentage of niobium (between 4-10 at %), not only with 7 at % as in the present investigation. Also, atmosphere with higher content of SO2 should be tested. Another problem is to optimize the surface integrity including surface roughness and sublayer properties. Practical implications: One of practical outcomes is to select the thermal conditions and surface preparation technology which guarantee the reduction of oxidation in 9%O2+0.3%SO2+N2 atmosphere. It is recommended to use alloys with higher content of niobium. Originality/value: Original value of the paper is assessing of the oxidation resistance of Ti–46Al–7Nb–0.7Cr–0.1Si–0.2Ni-based intermetallic alloy at the conditions combining high temperature and sulphur-containing atmosphere. The novelty of this research deals with the mechanism of oxidation at such boundary conditions and its quantification. This knowledge can support the design of parts made of the intermetalic alloy. The problem considered is currently important for aeroplane and automotive industry, especially for gas turbine manufacturers.

Słowa kluczowe

EN

corrosion; intermetallics; oxidation; sulfidation

PL

korozja; ultenianie; azotowanie; siarkowanie

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2010
• Tom: Vol. 43, nr 1
• Strony: 252--259
• Opis fizyczny: Bibliogr. 19 poz., rys., tabl.

Twórcy

autor

Małecka J.

autor

Grzesik W.

• Opole University of Technology, P.O. Box 321, 45-271 Opole, Poland,

Bibliografia

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