Investigations of suitable hard coatings on nickel-based single-crystal superalloy (CMSX-4)

Nickel-based superalloys are most widely used for hot parts in aircraft turbines. The largest use of coatings on superalloys is on the components of the hot section. In the present study, we have investigated hard coatings on nickel-based single crystal superalloy (CMSX-4) for the development of advanced cutting tools, because CMSX-4 can be supplied with unilateral pores. The pores shall act to provide coolant (fluid or gases) through the tool directly to the cutting zone. To provide CMSX-4 with sufficient wear resistance for tool applications we have investigated aluminium titanium nitride (AlTiN) films deposited by reactive magnetron sputtering as well as super hardmicrocrystalline diamond films deposited by hot-filament activated chemical vapour deposition (HFCVD), using a silicon carbide (SiC) interlayer. The deposited films were characterized with respect to film adhesion, mechanical properties, surface morphology and microstructure.