Hot Corrosion and Oxidation Studies of Pure Nickel and Ni-Cr,Ni-Si and Ni-Cr-Si Alloys at 1000 C.

摘要

Oxidation and 'hot corrosion' studies were made at 1000C on pure Ni, Ni-Cr, Ni-Si and Ni-Cr-Si. Oxidation of the pure Ni and Ni-Cr alloys followed Wagner's parabolic relationships quite closely while the oxidation rates of Ni-Si alloys, with Si contents varying up to 10 wt%, varied in a relatively erratic manner as Si contents were increased. At high Si contents in these alloys, rates of oxidation were considerably reduced. In the ternary alloys, Ni-10Cr-1Si displayed an almost unique resistance to oxidation. X-ray and microprobe studies were made on the scales developed in both the oxidation and 'hot corrosion' studies. Although it was felt that the resistance of the high silicon alloys was primarily due to the formation of SiO2, no direct evidence for this phase was found in either the x-ray or microprobe studies. Thus, it appears that relatively thin layers, of SiO2 or other phases, are responsible for the inertness of these alloys.