Deposition of Si-DLC film and its microstructural, tribological and corrosion properties

Abstract

Silicon-incorporated diamond-like carbon (Si-DLC) films were deposited using a bipolar-type plasma based ion implantation and deposition technique, and the effects of Si-incorporation on the microstructural, tribological, anti-corrosion and lubricant bonding properties of the Si-DLC films were investigated. The analysis of Raman spectroscopy exhibited that the sp 3 bonds in the DLC film increase due to Si addition. XPS analysis revealed that a thick oxide layer exists on the Si-DLC film surfaces. These explain the high lubricant bonding properties of the Si-DLC films compared to that of the Si-free DLC films. The silicon oxide layer on the Si-DLC film and the transferred silicon oxide layer on the steel ball prevents from the metal/ DLC contact between the Si-DLC film and steel ball when sliding, which results in a low friction. Incorporation of Si in DLC films led to significant improvements in the corrosion resistance due to low internal stress and thick insulating oxide layer.

Achieving Low Tribological Moisture Sensitivity by a-C:Si:Al Carbon-based Coating

“…11, revealed an apparent shift of Si2p peak from 100.3 to 102.3 eV, indicating that some SiC was converted to SiO x during the sliding friction. Hence, superior tribological performances of the as-fabricated a-C:Si and a-C:Si:Al coatings should be attributed to the formation of low shear strength colloidal silica (or SiO x (OH) y ) tribofilm by the tribochemical reaction of Si or SiC with H 2 O molecule on contact area under high relative humidity conditions [13,16,17]. Moreover, a-C:Si:Al coating presented better tribological performances compared with a-C:Si under high relative humidity becauseof its good combining mechanical properties.…”

“…Therefore, many researchers have devoted to the preparation of carbon-based coatings by doping additional elements to overcome those drawbacks. Among those studies, silicon incorporation in the carbon-based coatings has been widely studied and was reported as being effective in improving tribological performances in ambient humid air and water conditions by alleviating internal stress and preventing generation of micro-cracks and partial ruptures in wear tracks [13][14][15][16]. Moreover, other explanations for that effect have been offered, including the formation of SiO 2 at the frictional interface and an increase in sp 3 hybridization resulting in a less graphitic carbon [17][18][19][20].…”

Structure and tribological properties of DLC:Si/AlCrN low friction thin film

“…Parameter describing the nature of sp 2 bond are the ratio of peaks intensities [19,20]. If the silicon content was higher than the ID/IG ratio would be smaller [17,21]. The ID/IG ratio for DLC:Si/AlCrN in this case is 0.73.…”

Tribo-pair dependence of friction and wear moisture sensitivity for a-C:Si:Al carbon-based coating

“…8, have confirmed that an apparent shift of Si2p peak from 100.3 eV to 102.7 eV as the relative humidity increased from R.H. 5% to 90%. Hereby, under high relative humidity conditions, the improved tribological performances of as-fabricated a-C:Si:Al coating should be attributed to the formation of low shear strength colloidal silica (or SiO x (OH) y ) tribo-film by the tribo-chemical reaction of Si or SiC with H 2 O molecule on contact surfaces in the case of Si 3 N 4 , SiO 2 and GCr15 counterparts [11,14,15]. In addition, the Si-based ceramics showed that the chemical resultant such as SiO 2 or SiO x would be formed on the friction contact surface supposed as reaction (1) [34,35].…”

“…Consequently, many researchers have devoted to the preparation of DLC coatings by doping additional elements to overcome high tribological moisture sensitivity. Among those studies, Si incorporation in the DLC coatings has been widely studied and was confirmed as being effective in improving tribological moisture sensitivity by alleviating internal stress and preventing generation of micro-cracks and partial ruptures in wear tracks [11][12][13][14]. Moreover, other explanations for that effect have been offered, including the formation of SiO 2 at the frictional interface and an increase in sp 3 hybridization resulting in a less graphitic carbon [15][16][17][18].…”