Effect of deposition temperature on the morphology, structure, surface chemistry and mechanical properties of magnetron sputtered Ti70-A130 thin films on steel substrate

The present study investigates the effect of deposition temperature (ambien t and liquid N-2 temperatures) and sputtering power on the mechanical and c hemical properties of magnetron sputtered Ti3Al thin films on 316 stainless steel substrates. Film structure and morphology are investigated using X-r ay diffraction (XRD), scanning electron microscopy (SEM) and transmission e lectron microscopy (TEM), Films deposited at liquid N-2 temperature showed a dense nanocrystalline structure, whereas ambient temperature deposited fi lms showed voids and discontinuities in their columnar grain morphology as evident from TEM analysis. A detailed analysis of the surface chemistry of DC-magnetron sputtered thin films is performed using X-ray photoelectron sp ectroscopy (XPS). Glancing angle XPS studies are carried out to study the c hemistry at a few layers beneath the surface and monitor changes in thin fi lm stoichiometry. Surface oxides are always present in the films and are mo re prominent in ambient temperature deposition. Higher power leads to an en hanced metallic Ti3Al component as detected from XPS Al(2p) and Ti(2p) line s. Films deposited at liquid N-2 temperature are nanocrystalline and stoich iometric (Ti/Al similar to 3:1) and showed improved hardness than those dep osited at ambient temperatures under similar sputtering conditions and cons tant film thickness. The hardness of the films increases with increased spu ttering power at ambient temperature deposition. (C) 2001 Elsevier Science B.V. All rights reserved.