Thin WBx and WyTi1−yBx films deposited by combined magnetron sputtering and pulsed laser deposition technique

Abstract

The coatings of tungsten borides (WBx) and tungsten borides doped with titanium (WyTi1−yBx) were deposited by using combined magnetron sputtering - pulsed laser deposition technique. In the case of WBx coatings, pure tungsten target was evaporated by a laser pulse at 1064 nm wavelength and pure boron target was sputtered by a magnetron. In the case of WyTi1−yBx coatings, the W2B5 target was sputtered by the magnetron and titanium target was evaporated by the laser pulse at 1064 nm wavelength. The content of titanium dopant changed from 1.1 to 5.5 at.%. The microstructure, chemical and phase composition of deposited coatings were investigated by means of Scanning Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, X-Ray Photoelectron Spectroscopy and X-Ray Diffractometry, respectively. The Vickers hardness and Young's modulus were determined by using the nanoindentation test. Nanocrystalline WB coatings with dominant WB2 phase were obtained at a substrate temperature of 520 °C. The coatings were superhard with a hardness of 47–50 GPa and the mean value of surface roughness was <6 nm. The WBx coatings doped with 5.5 at.% Ti had hardness similar to the coatings sputtered by magnetron from W2B5 target.