Mechanisms for compositional variations of coatings sputtered from a WS2 target

Särhammar, Erik; Strandberg, Erik; Sundberg, Jill; Nyberg, Harald; Kubart, Tomáš; Jacobson, Staffan; Jansson, Ulf; Nyberg, Tomas

doi:10.1016/j.surfcoat.2014.04.066

Cited by 31 publications

(19 citation statements)

References 14 publications

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“…The coating deposited with −200 V has a significantly lower thickness equal to 45 nm, which results from shorter deposition time rather than from the bias voltage itself. The WS 2 monolayer, by contrast, is seen to have a uniform thickness and a columnar microstructure similar to that observed by other researchers [21,22]. The images of DLC-WS 2 coatings do not allow us to distinguish separate layers, although the DLC macroparticles can be noticed.…”

Section: Coating Structure and Compositionsupporting

confidence: 79%

“…Except for the WS 2 monolayer and DLC-WS 2 d, it can be observed that the amount of the Al is lower than for DLC. A larger amount of Al adherent can be noticed for the WS 2 monolayer, confirming the degradation of its tribological properties in the wet environment [21] and rapid wear caused by hard AlSi alloy. For DLC-WS 2 c and d, crater and abrasive flank wear occurred.…”

Section: Dlc-ws 2 Multilayersmentioning

confidence: 58%

“…Nevertheless, while the total deposition time was the same for all of the DLC-WS 2 coatings, the total thickness varies and is the lowest for the highest number of layers. The most probable reason is re-sputtering of WS 2 caused by bombardment of energetic particles-mostly highly charged ions depositing DLC coating [21].…”

Section: Coating Structure and Compositionmentioning

confidence: 99%

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DLC and DLC-WS2 Coatings for Machining of Aluminium Alloys

et al. 2019

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Machine-tool life is one limiting factor affecting productivity. The requirement for wear-resistant materials for cutting tools to increase their longevity is therefore critical. Titanium diboride (TiB2) coated cutting tools have been successfully employed for machining of AlSi alloys widely used in the automotive industry. This paper presents a methodological approach to improving the self-lubricating properties within the cutting zone of a tungsten carbide milling insert precoated with TiB2, thereby increasing the operational life of the tool. A unique hybrid Physical Vapor Deposition (PVD) system was used in this study, allowing diamond-like carbon (DLC) to be deposited by filtered cathodic vacuum arc (FCVA) while PVD magnetron sputtering was employed to deposit WS2. A series of ~100-nm monolayer DLC coatings were prepared at a negative bias voltage ranging between −50 and −200 V, along with multilayered DLC-WS2 coatings (total thickness ~500 nm) with varying number of layers (two to 24 in total). The wear rate of the coated milling inserts was investigated by measuring the flank wear during face milling of an Al-10Si. It was ascertained that employing monolayer DLC coating reduced the coated tool wear rate by ~85% compared to a TiB2 benchmark. Combining DLC with WS2 as a multilayered coating further improved tool life. The best tribological properties were found for a two-layer DLC-WS2 coating which decreased wear rate by ~75% compared to TiB2, with a measured coefficient of friction of 0.05.

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Section: Coating Structure and Compositionsupporting

confidence: 79%

Section: Dlc-ws 2 Multilayersmentioning

confidence: 58%

Section: Coating Structure and Compositionmentioning

confidence: 99%

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DLC and DLC-WS2 Coatings for Machining of Aluminium Alloys

et al. 2019

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“…One reason for the significantly lower Si content within our coatings with respect to the compound targets are the scattering effects promoted by the high deposition pressure of 1 Pa. These effects are not that pronounced for heavier elements, such as molybdenum [31]. The coatings prepared with the three elementary targets (Si: 3 inch, B: 2 inch, Mo: 2 inch) guarantees increased Si and B contents in comparison to the previous target set up.…”

Section: Resultsmentioning

confidence: 81%

Thermal stability and mechanical properties of boron enhanced Mo–Si coatings

Riedl

Vieweg

Limbeck

et al. 2015

Surface and Coatings Technology

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“…This is especially clear for the coatings deposited at high temperature, where the W content is almost constant, regardless of N content. It can be noted that the S/W ratio is well below 2 for all coatings, also those without N. Substoichiometry with respect to S is common in coatings deposited by sputtering from a WS 2 target, and the resulting sulphide can be described as WS x with x b 2 [14][15][16]. The presence of contaminations was checked by XPS depth profiles, and the W-S-N coatings contain approximately 2 at.% of O, and no C. More O and some C was detected for the W-S coatings, which are more porous and thus have adsorbed atmospheric contaminations not only on the outermost surface.…”

Section: Chemical Structural and Mechanical Propertiesmentioning

confidence: 90%

Influence of composition, structure and testing atmosphere on the tribological performance of W–S–N coatings

Sundberg

Nyberg

Särhammar

et al. 2014

Surface and Coatings Technology

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W-S-N coatings deposited by reactive magnetron sputtering offer the possibility of ultra-low friction in unlubricated sliding. In this work, W-S-N coatings of different composition and structure have been deposited, characterised and evaluated with respect to the tribological performance and tribofilm formation. The composition was varied by changing the flow of N 2 into the deposition chamber, leading to N contents ranging from 0 to 47 at.%. W-S-N coatings deposited without substrate heating are amorphous, while substrate heating results in coatings containing nanocrystalline tungsten sulphide (WS x ) for low N contents, and nanocrystalline tungsten nitride (W y N) at a high N content. The coatings were tribologically tested against steel balls in four different atmospheres-dry N 2 , dry air, humid N 2 and humid air-to study the effects of atmospheric O 2 and H 2 O both separately and simultaneously. In dry N 2 , all coatings exhibited an excellent performance with very low friction (μ ≈ 0.02) and wear. Notably, this included the N-richest and hardest coating, containing nanocrystalline W y N and only 13 at.% of S. The friction and wear increased on changing the atmosphere, in the order of dry airhumid N 2 -humid air. In these three non-inert atmospheres, the friction and wear also increased with increasing N content of the coating. It is thus concluded that the presence of O 2 , the presence of H 2 O, and a high N content (i.e., low W and S contents) are three factors increasing the risk of high friction and wear, especially when occurring together. Raman spectroscopy mapping of the contact surfaces on the coatings and the balls showed that low friction and wear is connected to the presence of WS 2 tribofilms in the contact, and that the three previously mentioned factors affect the formation and function of this tribofilm.

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Mechanisms for compositional variations of coatings sputtered from a WS2 target

Cited by 31 publications

References 14 publications

DLC and DLC-WS2 Coatings for Machining of Aluminium Alloys

DLC and DLC-WS2 Coatings for Machining of Aluminium Alloys

Thermal stability and mechanical properties of boron enhanced Mo–Si coatings

Influence of composition, structure and testing atmosphere on the tribological performance of W–S–N coatings

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