Characterisation of a High-Power Impulse Magnetron Sputtered C/Mo/W wear resistant coating by transmission electron microscopy

Sharp, J. H.; Müller, Itzel Castillo; Mandal, Paranjayee; Abbas, Ali; Nord, Magnus; Doye, Alastair; Ehiasarian, Arutiun P.; Hovsepian, P.Eh.; MacLaren, Ian; Rainforth, W.M.

doi:10.1016/j.surfcoat.2019.08.007

Cited by 6 publications

(3 citation statements)

References 31 publications

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“…Thus substrates deposited using one-fold rotation received a higher ad-atom flux and ion energies compared to those with three-fold rotation [51]. In other words, in three-fold rotation the substrate moved further away and closer to the plasma region influencing the plasma exposure time and deposition rate [52,53,54]. In this work, 2D coatings deposited with one-fold rotation, a high silicon target power and an N/Si ratio close to 1 (ranging from 0.98 to 1.03) showed higher coating densities compared to the 3D coatings (with a N/Si ratio ranging from 0.78 to 0.95).…”

Section: Discussionmentioning

confidence: 99%

The Effect of Coating Density on Functional Properties of SiNx Coated Implants

et al. 2019

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Ceramic coatings may be applied onto metallic components of joint replacements for improved wear and corrosion resistance as well as enhanced biocompatibility, especially for metal-sensitive patients. Silicon nitride (SiNx) coatings have recently been developed for this purpose. To achieve a high coating density, necessary to secure a long-term performance, is however challenging, especially for sputter deposited SiNx coatings, since these coatings are insulating. This study investigates the time-dependent performance of sputter-deposited SiNx based coatings for joint applications. SiNx coatings with a thickness in the range of 4.3–6.0 µm were deposited by reactive high power impulse magnetron sputtering onto flat discs as well as hip heads made of CoCrMo. SiNx compositional analysis by X-ray photoelectron spectroscopy showed N/Si ratios between 0.8 and 1.0. Immersion of the flat disks in fetal bovine serum solution over time as well as short-term wear tests against ultra-high molecular weight polyethylene (UHMWPE) discs showed that a high coating density is required to inhibit tribocorrosion. Coatings that performed best in terms of chemical stability were deposited using a higher target power and process heating.

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Section: Discussionmentioning

confidence: 99%

The Effect of Coating Density on Functional Properties of SiNx Coated Implants

et al. 2019

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“…Sci. 2021, 11, 10189 9 of 22 carbide phases (WC, W2C and Mo2C) in these coatings [21,28], where C4 and C6 particularly contained more metal carbide phases due to their high Mo+W content and therefore high hardness as compared to C2. Similarly, average elastic modulus values of ~194.5, ~236.2 and ~268.5 GPa were observed for C2, C4 and C6, respectively.…”

Section: Coating Microstructure and Compositionmentioning

confidence: 97%

“…A high C/(Mo+W) ratio of C2 led to an average nano-hardness value of ~1335.8 HV, whereas both C4 and C6 showed average nano-hardness values of ~1677.5 and ~1702.4 HV, respectively, due to low C/(Mo+W) ratios. This could be directly linked to the presence of hard carbide phases (WC, W 2 C and Mo 2 C) in these coatings [21,28], where C4 and C6 particularly contained more metal carbide phases due to their high Mo+W content and therefore high hardness as compared to C2. Similarly, average elastic modulus values of ~194.5, ~236.2 and ~268.5 GPa were observed for C2, C4 and C6, respectively.…”

Section: Coating Microstructure and Compositionmentioning

confidence: 99%

Influence of Carbon: Metal Ratio on Tribological Behavior of Mo-W-C Coating

Mandal

2021

Applied Sciences

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Mo-W-C coatings with three different C/(Mo+W) ratios (5:1, 2.8:1 and 2.2:1) were deposited by using combined unbalanced magnetron sputtering (UBMS) and high-power impulse magnetron sputtering (HIPIMS) technology. The influence of the C/(Mo+W) ratio on coating microstructure and related tribological properties at ambient temperature and at 200 °C were studied in lubricated condition (up to 7500 m and 1800 m of sliding distances, respectively). Results showed that a decrease in the C/(Mo+W) ratio could be correlated with an increase in coating thickness, adhesion strength, hardness and elastic modulus values, and a decrease in the degree of graphitization. At ambient temperature, outstanding tribological properties (very low friction and negligible wear) were observed irrespective of the C/(Mo+W) ratio. At 200 °C, low C/(Mo+W) ratios (2.8:1 and 2.2:1) were found particularly beneficial to achieve excellent tribological properties. The keys to significant friction reduction at 200 °C were (i) in situ formation of MoS2 and WS2 due to tribo-chemical reactions and (ii) presence of amorphous carbon debris particles in the protective tribolayer. With an increase in sliding distance, the tribolayer gradually lowered the friction coefficient by protecting both the coating and counterpart from severe wear. On the other hand, a high C/(Mo+W) ratio (5:1) led to low friction but noticeable abrasive wear at 200 °C.

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