Authors: Patrice Berthod
Publish Date: 2007/06/05
Volume: 68, Issue: 1-2, Pages: 77-96
Abstract
Two simple cast nickel alloys Ni–30Cr–02C and Ni–30Cr–08C were oxidized at 1000 1100 and 1200°C Their behaviors were characterized using thermogravimetry techniques and their parabolic and chromia volatilization constants were determined by analyzing the hboxm cdot frachboxdmhboxdt versus −m curves The constants obtained were generally in good agreement with experimental massgain kinetics and chromiumbalance aspects A higher carbon content ie a higher carbides density leads to higher values of the transient linearoxidation constant K l of the parabolic constant K p and obviously also of the volatilization constant K v Chromium diffusion coefficients through the zone affected by oxidation were calculated from the oxidation kinetics and chromium gradients They increase when the carbide density increases
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