FACTORS AFFECTING THE NITRIDATION BEHAVIOR OF FE-BASE, NI-BASE, AND CO-BASE ALLOYS IN PURE NITROGEN

The behavior of alloys in nitrogen at high temperature is relevant to many industrial applications. Embrittlement due to internal nitride fo rmation is the principal problem encountered in service. In this study , the nitridation resistance of a series of alloys in pure nitrogen at 1093-degrees-C was investigated. For Fe-base, Ni-base, and Co-base al loys the amount of nitrogen absorbed and the nature and morphology of the nitrides formed was studied. It was found that alloys rich in nick el were most resistant to nitridation. Most of the alloys formed inter nal chromium nitrides. The Al-containing alloys with about 4.5 wt% Al, formed a surface scale of AlN and was very resistant to nitridation a ttack.