Mechanical Properties Influence on the Tribological Behavior of Flame Spraying Al2O3-TiO2 and WC-NiFeCr Coatings

This paper studies the influence of mechanical properties on the tribological behavior of Al₂O₃-TiO₂ and WC-NiFeCr coatings deposited by flame spray process. The application of both coatings was carried out with two different torches: Terodyn 2000 and SuperJet Eutalloy.

Three different powder fabricated by Eutectic Castolin were used to obtain the coatings: ProXon 21021 (Ni-10%Al) -used as bond coat between the substrate (AISI O1 steel) and the ceramic or cermet layer, MetaCeram 25060 (Al₂O₃-40 %TiO₂) and TungTec 10112 (WC-40 %NiFeCr) used as final coating.

Mechanical properties (hardness and toughness) of the four coatings were measured by indentation tests and the toughness was calculated by the Lawns–Evans–Marshall equation.

Tribological behavior was determined by pin on disk technique (the polyethylene was used as the disk while the coatings on AISI/SAE O1 steel were used as the pin). This tribological couple was used in order to determine the capacity of these coatings to increase the use life of tools for cutting and shape of polyethylene. The tests were carry out with 1.047 m/seg of linear speed between the coated pin and the polyethylene disk, 0.5 MPa as contact pressure, 2820 m of sliding distance and a disk temperature varied between 108 and 112°C.

Results showed that the coatings having the highest toughness present the best tribological behavior when they are in contact with the polyethylene while any effect of the hardness on the wear resistance was observed.