Mechanical and corrosion properties of hydrogen-free DLC coatings prepared on degradable as-extruded WE43 alloy using FCVA technology

magnesium alloys have great potential for medical applications. However, their rapid degradation has limited their development. Hydrogen-free DLC coatings were deposited on WE43 using filtered cathodic vacuum arc (FCVA) technology. The influence of different negative bias voltages on the microstructure and mechanical and corrosion properties of the coatings was systematically analyzed. The research demonstrated that application of a negative bias voltage altered the surface morphology of hydrogen-free DLC coatings with amorphous structures. In addition, the coatings exhibited a decrease in hardness and elastic modulus until the negative bias voltage reached -75 V, indicating that the increase may be attributed to the rise in sp(2) cluster size and the fall in sp(3) content. Furthermore, electrochemical experiments demonstrated that the coated samples exhibited superior anti-corrosion properties. The coatings deposited at -75 V displayed the highest corrosion resistance, as evidenced by their minimal corrosion current (4.53 mu A center dot cm(-2)), maximal film resistance (2576 omega center dot cm(2)), and charge transfer resistance (3171 omega center dot cm(2)). Hydrogen evolution experiments indicated that the hydrogen-free DLC coatings effectively reduced WE43 corrosion and hydrogen gas production.