Assessment of CpTi Surface Properties after Nitrogen Ion Implantation with Various Doses and Energies

To improve medical pure magnesium corrosion and wear resistance, the advanced plasma implantation technology were used to implanted medical pure magnesium with nitrogen ions under certain conditions, obtaining a certain depth of nitrogen ion implantation layer, and to study the surface properties of the implantation layer. The sample after ion implanted, the surface morphology, phase composition were analyzed, and have electro chemical corrosion tests, friction and wear tests, the results showed that: pure magnesium by nitrogen ion implantation, can be obtained a surface organizations which whole flat, compact, no surface cracks and holes; the surface implantation layer mainly composed of Mg and MgO, also found a small amount of Mg3N2, which is also the main reason for corrosion and wear resistance improved; compared to pure magnesium base, nitrogen ion implantation (process conditions: implantation energy: 40KeV, implantation dose: 3×1017ions/cm2, control temperature: 200°C) improved the corrosion resistance of the sample, but not obvious, about 1.2%; however, the friction coefficient decreased significantly, approximately 61%, the amount of wear also reduced significantly, about 74%, this means that, its wear resistance has been improved significantly. This study provides a reference to improve the surface properties of pure magnesium and be learned to develop a more reasonable parameters for further study of medical pure magnesium by ion implantation of nitrogen.

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Microstructure and Surface Properties of Silver after High Dose Nitrogen Ion Implantation

Journal of Fusion Energy ◽

10.1007/s10894-010-9361-4 ◽

2010 ◽

Vol 30 (2) ◽

pp. 126-129 ◽

Cited By ~ 1

Author(s):

A. H. Sari ◽

A. Akhavan ◽

M. K. Salem

Keyword(s):

Ion Implantation ◽

Surface Properties ◽

High Dose ◽

Nitrogen Ion Implantation ◽

Nitrogen Ion

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Effect of Nitrogen Ion Implantation on the Cavitation Erosion Resistance and Cobalt-Based Solid Solution Phase Transformations of HIPed Stellite 6

Materials ◽

10.3390/ma14092324 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2324

Author(s):

Mirosław Szala ◽

Dariusz Chocyk ◽

Anna Skic ◽

Mariusz Kamiński ◽

Wojciech Macek ◽

...

Keyword(s):

Plastic Deformation ◽

Stainless Steel ◽

Ion Implantation ◽

Phase Transformations ◽

Erosion Rate ◽

Cavitation Erosion ◽

Matrix Phase ◽

Nitrogen Ion Implantation ◽

Stellite 6 ◽

Nitrogen Ion

From the wide range of engineering materials traditional Stellite 6 (cobalt alloy) exhibits excellent resistance to cavitation erosion (CE). Nonetheless, the influence of ion implantation of cobalt alloys on the CE behaviour has not been completely clarified by the literature. Thus, this work investigates the effect of nitrogen ion implantation (NII) of HIPed Stellite 6 on the improvement of resistance to CE. Finally, the cobalt-rich matrix phase transformations due to both NII and cavitation load were studied. The CE resistance of stellites ion-implanted by 120 keV N+ ions two fluences: 5 × 1016 cm−2 and 1 × 1017 cm−2 were comparatively analysed with the unimplanted stellite and AISI 304 stainless steel. CE tests were conducted according to ASTM G32 with stationary specimen method. Erosion rate curves and mean depth of erosion confirm that the nitrogen-implanted HIPed Stellite 6 two times exceeds the resistance to CE than unimplanted stellite, and has almost ten times higher CE reference than stainless steel. The X-ray diffraction (XRD) confirms that NII of HIPed Stellite 6 favours transformation of the ε(hcp) to γ(fcc) structure. Unimplanted stellite ε-rich matrix is less prone to plastic deformation than γ and consequently, increase of γ phase effectively holds carbides in cobalt matrix and prevents Cr7C3 debonding. This phenomenon elongates three times the CE incubation stage, slows erosion rate and mitigates the material loss. Metastable γ structure formed by ion implantation consumes the cavitation load for work-hardening and γ → ε martensitic transformation. In further CE stages, phases transform as for unimplanted alloy namely, the cavitation-inducted recovery process, removal of strain, dislocations resulting in increase of γ phase. The CE mechanism was investigated using a surface profilometer, atomic force microscopy, SEM-EDS and XRD. HIPed Stellite 6 wear behaviour relies on the plastic deformation of cobalt matrix, starting at Cr7C3/matrix interfaces. Once the Cr7C3 particles lose from the matrix restrain, they debond from matrix and are removed from the material. Carbides detachment creates cavitation pits which initiate cracks propagation through cobalt matrix, that leads to loss of matrix phase and as a result the CE proceeds with a detachment of massive chunk of materials.

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