Dry sliding, slurry abrasion and cavitation erosion of composite layers reinforced by TiC fabricated in situ in cast steel and gray cast iron

To improve the wear resistance of low-carbon steel and gray cast iron, TiC/Fe-type composite layers were fabricated using reactive casting coatings. The in situ synthesis reaction of titanium carbide (TiC) was initiated by the high temperature of the liquid alloy (SHS – self-propagating high-temperature synthesis). The structure, microstructure, hardness, and wear properties of the composite layers were investigated. Wear examinations were carried out in various environments: dry sliding, slurry abrasion, and cavitation erosion in slurry. An observation of the microstructure revealed the presence of TiC particles that were well-bonded with both types of matrices. The mechanical properties showed an almost three-fold increase in the hardness within the area of the composite layer as compared to the base alloy (1000HV1). These results were reflected in a slurry abrasion test that indicated less than half of the weight loss as compared to the monolithic matrix of the composite castings. The cavitation erosion wear mechanism of the composite layers was examined for the first time taking the surface of the sample into consideration (after polishing and as cast – casting skin). The polished surfaces were characterized by higher resistance to cavitation erosion than the as-cast samples. On the other hand, the casting skin acted beneficially as an extra coating that prevented the castings’ cores from cavitation erosion damage.