High velocity oxy-fuel (HVOF) spraying was used to coat Ti(Al,O)/ powder onto the SS41 steel plate. Macrostructure of the coated specimen has been investigated by scanning electron micrograph (SEM). High temperature oxidation behavior of the coated specimen and SS41 steel have been studied. From the results of SEM observation, Ti(Al,O)/ powder was coated well onto the substrate SS41 steel. Porosity onto the coated layer was only 0.38%. The oxidation results showed that Ti(Al,O)/ powder coated SS41 steel have improved little oxidation resistance at in air, but improved remarkably oxidation resistance at in air compare to the substrate SS41 steel.

Friction coefficient of SM45C steel was surprisingly reduced with and gas during plasma sulf-nitriding. During the plasma sulf-nitriding, 100-700 sccm of gas and 100 sccm of gas were added and working pressure and temperature were 2 torr, , respectively. As gas amount increased over 500 sccm, flake-like structures were developed on top of the nitriding layer and grain size of the nitriding layer were about 100 nm. The friction coefficient for the sample treated plasma sulf-nitriding under gas was 0.4 - 0.5. The structure became more finer and amorphous-like along with gas and the nano-sized surface microstructures resulted in high hardness and significantly low friction coefficient of 0.2.

The age hardening behavior and mechanical properties of an extruded Al-Zn-Mg-(Cu)-0.1 wt.%Sc alloy were investigated with the Sc addition and ageing temperature. The results showed that the compounds were formed by Sc addition and distributed preferentially along the extrusion direction. The age hardening of Al-Zn-Mg-Cu-0.1 wt.%Sc alloy which was treated by T6 process was more significant than that of Al-Zn-Mg-0.1 wt.%Sc alloy. The tensile property of Al-Zn-Mg-Cu+0.1 wt.%Sc alloy was also higher than that of Al-Zn-Mg-0.1 wt.%Sc alloy, which is 691 MPa and 584 MPa in strength and 9% and 11% in elongation, respectively.