Adrián Claver¹, Iván Fernández¹, José Antonio Santiago², Pablo Díaz-Rodríguez², José Fernández Palacio^1,3, Gonzalo García Fuentes^1,3, Iñaki Zalakain¹, José Antonio García^1
1Universidad Pública de Navarra (UPNA), Pamplona, Spain
²Nano4Energy, Madrid, Spain
³Centre of Advanced Surface Engineering, Cordovilla, Spain
Magnesium alloys have very interesting properties, are biocompatible and have low density, making them a very attractive option for applications such as the automotive industry, aeronautics, and Young modulus similar to bone for biomedical implants. However, their high corrosion rate and low wear resistance have limited their actual application. To address this problem, different coating and surface treatment strategies have been developed over the last few years, such as the use of PVD coatings. However, there is still a need to find a solution that meets the medical and engineering corrosion and wear protection requirements for this type of application. In this work, Ti/TiN coatings with different multilayer structures were deposited into ZK60 magnesium alloy via the High Power Impulse Magnetron Sputtering (HiPIMS). This technique has been used to improve the adhesion of these coatings and to ensure a structure that improves corrosion resistance. In the case of multilayer structures, the thickness of the layers and the deposition parameters have been varied in order to control the degradation rate of this type of substrates. On this way, biocompatible coatings with improved corrosion resistance and adhesion to the substrate have been achieved, combined with improvements in hardness, toughness, and wear resistance. Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and Glow discharge optical emission spectrometry (GD-OES) were used to analyze the structure and composition of the coatings. Tribological tests, scratch tests and nanoindentation were performed to obtain information about the mechanical and tribological properties of the coatings. With the dynamic mode of nanoindentation technique it was possible to study the properties of the multilayer structures. Electrochemical tests were performed to evaluate the corrosion resistance of the samples, as well as immersion tests were mass change and hydrogen evolution were controlled. The results have shown improved corrosion resistance in addition to good adhesion to the substrate and improved wear resistance of the ZK60 magnesium alloy substrate. The different results obtained for each layer configurations will allow to select the most suitable one for each application.