TiN films were deposited using High Power Impulse Magnetron Sputtering (HIPIMS) enabled four cathode industrial size coating system equipped with HIPIMS power supplies. The standard version of this system allows control over the ion bombardment during coating growth by varying the strength of the electromagnetic field of the unbalancing coils and bias voltage applied to the substrate. The coatings were produced in different coating growth conditions achieved in combined HIPIMS-direct current (DC) unbalanced magnetron sputtering (HIPIMS/UBM) processes where HIPIMS was used as an additional tool to manipulate the ionisation degree in the plasma. Four cathode combinations were explored with increasing contribution of HIPIMS namely 4UBM (pure UBM), 1HIPIMS+ 3UBM, 2HIPIMS+2UBM and 2HIPIMS (pure HIPIMS) to deposit TiN coatings. Optical emission spectroscopy (OES) measurements were carried out to examine the plasma generated by the various combinations of HIPIMS and UBM cathodes. The micro-structural study was done by scanning electron microscopy (SEM). X-ray diffraction (XRD) technique was used to calculate the residual stress and texture parameter. It has been revealed that the residual stress can be controlled in a wide range from-0.22 GPa to-11.67 GPa by intelligent selection of the degree of HIPIMS utilisation, strength of the electromagnetic field of the unbalancing coils and the bias voltage applied to the substrate while maintaining the stoichiometry of the coatings. The effect of the degree of HIPIMS utilisation on the microstructure, texture and residual stress is discussed. Combining HIPIMS with dc-UBM sputtering is also seen as an effective tool for improving the productivity of the deposition process.

Defect growth in multilayer chromium nitride/niobium nitride coatings produced by combined high power impulse magnetron sputtering and unbalance magnetron sputtering technique. Thin Solid Films, 636, 558-566.

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CoCrMo is a biomedical grade alloy which is widely used in the manufacturing of orthopaedic implants such as hip and knee replacement joints because of it has high hardness, high corrosion resistance, and excellent biocompatibility. However, the release of metal ions due to corrosion and wear of the alloy over time may cause allergic or other adverse reactions in some patients. To date, various surface modification techniques including nitriding, have been used to improve the performance of CoCrMo (F75) alloy.15 m 3 N -1 m -1 (-1100 V), which were one order of magnitude lower than the untreated substrate, Kc = 6 ×10 -14 m 3 N -1 m -1 . The Knoop microhardness (HK) of nitrided samples significantly increased by a factor of 5 (HK= 2750 at -1100 V) as compared to the untreated substrate, HK=525, demonstrating the high efficiency of the process. The samples nitrided at -700 V and -900 V exhibited enhanced corrosion resistance as compared to untreated alloy by avoiding the formation of CrN based compounds which adversely affect the corrosion performance.