The mechanical and tribological properties of titanium aluminium nitride coatings formed in a four magnetron closed-field sputtering system

Abstract

Titanium aluminium nitride coatings have been deposited onto rotating tool steel substrates of three different roughnesses using four unbalanced rectangular planar magnetrons arranged in a closed field configuration. Three of the magnetrons were fitted with titanium targets and the fourth with aluminium. By varying the magnetron powers and the speed of substrate rotation, coatings of chosen composition can be deposited as either multilayers or homogeneous alloys. The composition and morphology of the films have been investigated using X-ray diffraction and scanning electron microscopy, and their mechanical properties have been characterised by scratch testing and microhardness measurement. The tribological properties have been established by pin on disc testing against hemispherical tungsten carbide pins, using relocation profilometry to provide accurate measurements of wear depths less than the original surface roughness. Good correlation of the mechanical and tribological properties is reported.