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Development of new nickel alloys with low coefficient of thermal expansion

Conference ·
OSTI ID:901601
The present research is aimed at formulating low CTE nickel-base superalloys for use in the SOFC temperature range of 700 to 800C. Alloys based on the composition Ni-(12-22wt%)Cr were modified with W and Mo to lower CTE to on the order of 12 x 10-6 C-1. Mn was added to impart the formation of an outer Cr-Mn spinel, to minimize chrome vaporization. The reactive element Y was added in small amounts to enhance scale adhesion. Ingots were produced by Vacuum Induction Melting and Vacuum Arc Melting. The ingots were reduced to sheet by conventional thermal-mechanical processing. Linear variable differential transducer (LVDT) based dilatometer measurements were used to determine the thermal expansion of the alloys in accordance with ASTM standard E-228-85. Oxidation tests (in dry and wet air) were conducted at 750 and 800C to evaluate the corrosion resistance of the alloys. The results were compared to the behavior of Crofer 22APU and Haynes 230. Several of the custom alloys had CTEs in the useful range for interconnect application. Further, several compositions proved to be significantly more oxidation resistance than Crofer 22APU.
Research Organization:
Albany Research Center (ARC), Albany, OR
Sponsoring Organization:
USDOE
OSTI ID:
901601
Report Number(s):
DOE/ARC-2005-025
Country of Publication:
United States
Language:
English