Studies of Fe-40Al coatings obtained by high velocity oxy-fuel

Interesting properties that intermetallics possess have made them to be promising materials to be used either as bulk materials or as coatings, both at medium or elevated temperature environments. This group of materials possesses a long-range order, which can be kept by some intermetallics until their melting point, which is the main reason why they possess a good stability at high temperatures. Some other properties can be summarized as follows: high thermal conductivity; low density; great strength, particularly at high temperatures; good oxidation resistance at high temperatures (because of the formation of oxide films); low ductility, brittle fracture at room temperature. FeAl coatings from powder of nominal composition Fe-40Al-0.05 Zr (at.%) with 50 ppm B and I Wt-% Y2O3 have been prepared using high velocity oxy-fuel (HVOF) technique. Several standard spraying conditions have been assessed; some parameter variations from those standards intend to find optimal spraying conditions. The characterization has been carried out by DRX, EDS and Scanning Electron Microscopy. The results conclude that a major intermetallic FeAl phase has been obtained. Microhardness and wear properties have been evaluated for those coatings obtained with optimal conditions. Compared to room temperature sliding wear behaviour, the friction coefficient is reduced when the test is performed at 400 degrees C. (c) 2006 Published by Elsevier B.V.