Nitriding behaviour of the intermetallic alloy FeAl

Abstract

Abstract An iron-based intermetallic FeAl alloy was gas nitrided under well-defined conditions, and the influences of the process parameters, i. e., time, temperature, and nitriding potential on the layer formation, were investigated. Microstructural, morphological, and chemical characterization of the nitride layer was performed by means of glow discharge optical spectroscopy, electron probe microanalysis, scanning electron microscopy, X-ray diffraction, internal-stress measurement, hardness–depth profiles, and indentation fracture mechanics. Pin-on-disk tests were carried out to investigate the load-bearing capacity and wear resistance of the nitride layers. The formation of hexagonal AlN during the nitriding treatment leads to an increase in hardness of about 920 – 980 HV 0.025 and to a significant improvement of the wear resistance. Additional annealing tests proved the thermal stability of the nitride layer up to 950 °C.