Oxidation behavior of the B-modified silicide coating on Nb-Si based alloy at intermediate temperatures

摘要

A B-modified silicide coating on Nb-Si based alloy was prepared by the method of pack cementation. The oxidation resistance of the B-modified silicide coating was studied in the pest-oxidation temperature range (from 650 degrees C to 850 degrees C). Oxidation experiments show that the samples coated with B-modified silicide coating maintain low-rate oxidation and suffer from no pest oxidation at all experimental temperatures. The preferential oxidation of Ti and Si can suppress the formation of Nb2O5. Besides, the borosilicate scale with high fluidity can seal the cracks and pores in the scale. Thus, the occurrence of pest catastrophe is avoided.