The tribological properties of short range ordered W-B-C protective coatings prepared by pulsed magnetron sputtering

Abstract

The tribological properties of short range ordered W-B-C protective coatings prepared by pulsed magnetron sputtering Debnarova, S.

Reactive magnetron sputtering of tungsten target in krypton/trimethylboron atmosphere

“…The Er measured in our films follow the same trends previously described for hardness, see Fig. 8a and 8b, with the highest value of ~ 280 GPa for the film deposited with 10 sccm TMB at 500 o C and a lowest value of ~130 GPa for the film deposited at 900 o C. Similar as for the hardness, our Er ~ 280 GPa value is similar to the Er ~ 300 GPa reported by Debnárová et al [27] but lower than the ~ 450 GPa reported in the studies by Alishahi et al [26]. Furthermore, for W2C and WC1-x films containing 35 at.% C Palmquist et al [14] measured an E-moduli of ~ 450 GPa, i.e.…”

“…This is a consequence of the reaction between the Si(100) substrate and the film, resulting in formation of WSi2 at 700 and 800 o C or a Si rich surface at 900 o C as determined from our XRD and XPS measurements and where the reaction also yields an increased surface roughness seen from the loss of the silver-white color and metallic luster. The H varies in the range 23 to 31 GPa for films deposited with different TMB flows and at temperatures ≤ 600 o C; a closer inspection shows the lowest H values for the films deposited at temperatures of 200, 300 and 400 o C, with H = 23, 25, and 24 GPa, respectively.Our H values are comparable or even slightly higher than the reported HV of d-WC with 22 GPa for a 0001-oriented single-crystal[2] as well as to those reported for more carbon and boron rich W-B-C films by Alishahi et al[26] and Debnárová et al[27] with values in the range ~24 to ~29 GPa and ~23 GPa, respectively. In contrast, our H values are lower than the ~37 to ~47 GPa reported by Su et al[24] for d-WC films alloyed with ~4 to ~7 at.…”

“…The study shows that the composition of the films can be varied at low flows of C2H2, but with deposition of almost pure carbon films when the WB2 target is poisoned by C2H2. In two publications, Alishahi et al [26] and Debnárová et al [27] investigated growth of W-B-C films from magnetron sputtering of W, and B4C targets, in combination with pulsed sputtering of a C target. The applied experimental set-up with three separate sources allows for growth of films in a with a wide range of compositions and properties as reported by the authors but is less practical for industrial applications.…”

Temperature-Adaptive Ultralubricity of a WS2/a-C Nanocomposite Coating: Performance from Room Temperature up to 500 °C

“… 10 − 13 Some other temperature-adaptive lubricating materials allowing for diffusion-based and/or oxidation-based mechanisms can be potentially used over multiple thermal cycles in microlaminate architectures; 1 , 5 , 11 , 13 − 18 their metal or transition-metal suboxides including the so-called Magnéli phases (e.g., TiO x , MoO x , VO x , and WO x ) are suitable as middle temperature range lubricants. 11 , 12 , 19 , 20 Ceramic-enhanced coatings (particularly when comprising Ag) have been found to further lift the temperature threshold; yet, they generate higher coefficient of frictions (CoFs) (>0.2–1). 13 , 16 , 17 , 21 , 22 …”

Composition, Structure and Mechanical Properties of Industrially Sputtered Ta–B–C Coatings

“…Later, an ab-initio modeling of similar materials was performed and it was reported that crystalline Ta 2 BC and W 2 BC in particular are also promising candidates for experimental synthesis owing to their calculated elastic properties indicating their simultaneous high stiffness and moderate ductility [13]. Although experimental studies of coating systems like Ti-B-C [14][15][16][17][18][19][20], Ta-B-C [21], Nb-B-C [22], and W-B-C [19,[23][24][25][26][27][28] potentially leading to the formation of the X 2 BC crystalline structure have been published, no formation of the ternary crystalline X 2 BC phase other than Mo 2 BC has ever been reported [11,13].…”