Fig. 1 Schematic diagram of plasma immersion ion implantation (PIII) equipment [25]

Fig. 2 a Grazing incidence XRD patterns of unimplanted and ion-implanted magnesium alloy; b potentiodynamic polarization curves exposed to 3 wt% NaCl solution [36]. (Mg-00: unimplanted; Mg-22 to Mg-44: N ion-implanted)

Fig. 3 Depth profiles of chemical compounds of N implanted pure Mg, AM50 and AZ31 after the deconvolution of Al, Mg 2p states [32]

Fig. 4 Potentiodynamic polarization curves for the various untreated and implanted Mg alloys in 0.5 wt% NaCl solution at pH 6.5 [32]

Fig. 5 Cross-section HRTEM images of a and b SiNx/Ar/AZ31; c and d SiNx/Ar&N/AZ31. The inserted figure is the amplification of the square area in d [53]

Fig. 6 The OCP a and the corrosion resistance (the impedance of the EIS at 0.1 Hz) b variation with time during immersion in 3.5 wt% NaCl solution [53]

Fig. 7 a SEM surface and b cross-section images of the sample A1, c SEM cross-section image of the sample A2, d SEM cross-section image of the sample A3, e potential dynamic polarization curves of all samples [34]. (A0: AM60 substrate; A1: Single-layer MoS2-phenolic resin; A2: Nitrogen ion implantation/AlN/MoS2-phenolic resin; A3: Nitrogen ion implantation/AlN/CrAlN/MoS2-phenolic resin)

Fig. 8 XPS depth profiles: a coated AZ91 Mg alloy and b intermediate nitrided layer on the AZ91 Mg alloy; c potentiodynamic curves of the bare AZ91 Mg alloy and nitrided AZ91 Mg alloy samples after immersion in SBF for 48 h and coated AZ91 Mg alloy sample after immersion for 48 and 120 h [56]

Fig. 9 Cross-sectional morphologies and corresponding EDS results of AZ91D magnesium alloy coated with alternate Al/Ti multilayer followed by plasma nitriding at different temperatures for 8 h: a and d 375 °C; b and e 400 °C; c and f 425 °C; g polarization curves of specimens before and after modification [67]

Fig. 10 Photographs and schematics of developed atmospheric-pressure plasma treatment system: a schematic of APPJ treatment system; b schematic of APPJ generation component; c photograph of developed treatment system; and d SEM image of nozzle. Magnesium, oxygen, and nitrogen maps obtained by EPMA of surfaces of e untreated AZ31 Mg alloy and f AZ31 Mg alloy treated using atmospheric-pressure plasma [70]

Fig. 11 Schematic diagram of ceramic film deposition by LPCVD system [73]

Fig. 12 Schematic diagram of MBE [79]