Microstructural and compositional evolution of compound layers during gaseous nitrocarburizing
2000 (English)In: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 31, no 1, 195-211 p.Article in journal (Refereed) Published
Compound layers developed at 848 K during gaseous nitrocarburizing of iron and iron-carbon specimens were investigated for several combinations of N and C activities imposed at the specimen surface by gas mixtures of NH3, N-2, CO2, and CO. The microstructural evolution of the compound layer was studied by light microscopy and by X-raydiffraction analysis. Composition-depth profiles were determined by electron probe (X-ray) microanalysis. Layer growth kinetics was investigated by layer thickness measurements. The influence Of the N and C activities on the microstructural and compositional evolution and the growth kinetics of the compound layers formed is discussed for the iron substrate. The results indicate that the microstructure is governed by a fast C and a slow N absorption at the surface in an early stage of gaseous nitrocarburizing. The influence of carbon in the substrate on the microstructural and compositional evolutions and on the growth kinetics was evaluated from comparing the results obtained for: a: normalized Fe-0.8C alloy with those for iron under identical nitrocarburizing conditions.
Place, publisher, year, edition, pages
2000. Vol. 31, no 1, 195-211 p.
long-range order, growth-kinetics, iron nitride, nitrogen, thermodynamics, lattice
IdentifiersURN: urn:nbn:se:kth:diva-19486ISI: 000084763100020OAI: oai:DiVA.org:kth-19486DiVA: diva2:338178
QC 201005252010-08-102010-08-10Bibliographically approved