"A feasibility study on hybrid use of thermal spray coating and ultrasonic nanocrystal surface modification"

In order to improve the mechanical properties of thermal spray coating films, an ultrasonic nanocrystal surface modification (UNSM) technique has been applied before and after ceramic spray coating on the hot tool steel substrate. The surface microstructure of the untreated and UNSM-treated specimens will be examined by SEM, EDS and XRD. The mechanical properties of the specimens will be measured by nanoindentation and nanoscrtach tests. The tribological properties of the specimens will be assessed using a ball-on-disk tribometer against a bearing steel (SAE52100) ball at two different temperatures under dry reciprocating conditions. It would be expected that the UNSM-treated specimens have much denser microstructure, smoother surface, better adhesion, lower friction and higher resistance to wear compared to those of the untreated specimens. The results of this study will reveal that hybrid use of thermal spray coating and UNSM technique is meaningful to bring synergy effect of two emerging surface technologies.