Friction and wear studies of Nimonic 80A and 21-4N valve materials against GGG-40 under dry sliding conditions, at temperatures ranging from 50 oC to 500 oC, are presented in this paper. Friction coefficient was found to continuously decrease with time for all tests with prominent running-in behavior seen in the 50 oC and 500 oC tests. Higher friction coefficient and wear was observed at 300 oC, as compared to that at 50 oC and 500 oC. Formation of oxide Fe3O4, at 300 oC, was confirmed by Raman spectroscopy, which resulted in a higher friction coefficient and wear. Raman spectroscopy further revealed the presence of a-Fe2O3, hematite, in most cases, with presence of oxides of Ni-Cr and Ni-Fe as well. EDS results on the samples confirmed the same. Wear at 500 oC was found to be the least for both the valve materials with SEM confirming the formation of well developed glaze layers.