Studies on the oxidation behaviour of intermetallic compounds

The oxidation behaviour of the AB5 type intermetallic compounds CaNi5 and LaNi5 has been studied at different temperatures ranging from 100 to 800° C. The kinetic results indicate that the element A (Ca, La) is first oxidized rapidly followed by slower oxidation of nickel. X-ray diffractograms of the oxidized LaNi5 show the formation of ternary phases like LaNiO3 and La2NiO4 at temperature as low as 400° C. A comparison between the oxidation behaviour of the two compounds reveals that CaNi5 is more resistant to oxidation and decomposition than the LaNi5 system. © 1988 Chapman and Hall Ltd.