Modification of metals by plasma immersion ion implantation

Abstract While plasma immersion ion implantation (PIII) has shown a remarkable success story in its development, recently it appears to be stagnating. This review tries to shed some light on the dichotomy between the industrial success of plasma doping and the superficial dearth of industrial applications for functional coatings or biomedical implants. It is surmised that the use of high voltage pulses between 5 and 25 kV leads to excessive heat deposition, reducing the effective deposition rate, and large gradients in sputtering across the substrate surface, which is more detrimental than those in comparable recent methods, e.g. high power impulse magnetron sputtering (HiPIMS). However, the peculiarities of PIII can still be used rewardingly when focusing more on model experiments to understand specific fundamentals of ion surface interactions. The first example concentrates on dynamic measurements of secondary electron emission coefficients measured while the surface is actually changing. Another example shows how a combination of dedicated experiments can help to elucidate information on the formation of expanded austenite formed by nitrogen insertion into austenitic stainless steel. Nevertheless, for that case there are still open questions requiring further work.