The Influence of Preparation Conditions on the Structural Properties and Hardness of Diamond-Like Carbon Films, Prepared by Plasma Source Ion Implantation

Role of Cr Element in Highly Dense Passivation of Fe-Based Amorphous Alloy

The effect of the Cr element on the corrosion behavior of as-spun Fe72-xCrxB19.2Si4.8Nb4 ribbons with x = 0, 7.2, 21.6, and 36 in 3.5% NaCl solution were investigated in this work. The results show that the glass formability of the alloys can be increased as Cr content (cCr) is added up to 21.6 at.%. When cCr reaches 36 at.%, some nanocrystals appear in the as-spun ribbon. With increasing cCr content, the corrosion resistances of as-spun Fe-based ribbons are continually improved as well as their hardness properties; during the polarization test, their passive film shows an increase first and then a decrease, with the highest pitting potential as cCr = 7.2 at.%, which is confirmed by an XPS test. The dense passivation film, composed of Cr2O3 and [CrOx(OH)3-2x, nH2O], can reduce the number of corrosion pits on the sample surface due to chloride corrosion and possibly be deteriorated by the overdosed CrFeB phase. This work can help us to design and prepare the highly corrosion-resistant Fe-based alloys.

Diamond-Like Carbon (DLC) Coatings: Classification, Properties, and Applications

DLC coatings have attracted an enormous amount of interest for science and engineering applications. DLC occurs in several different kinds of amorphous carbon materials. Owing to the extensive diversity in their properties, DLC coatings find applications in mechanical, civil, aerospace, automobile, biomedical, marine, and several other manufacturing industries. The coating life of DLC is predominately influenced by its constituent elements and manufacturing techniques. Numerous researchers have performed multiple experiments to achieve a robust understanding of DLC coatings and their inherent capabilities to enhance the life of components. In this review, a wide range of DLC coatings and their classification, properties, and applications are presented. Their remarkable performance in various applications has made DLC coatings a promising alternative over traditional solitary-coating approaches.

Hydrophobic Anti-Reflective Coating of Plasma-Enhanced Chemical Vapor Deposited Diamond-Like Carbon Thin Films with Various Thicknesses for Dye-Sensitized Solar Cells

Diamond-like carbon (DLC) thin films, prepared by a radio frequency plasma-enhanced chemical vapor deposition (PECVD) system, were investigated for application as an anti-reflective coating (ARC) for dye-sensitized solar cells (DSSCs) with a change in film thickness. The strength of the Raman spectrum, G-peak position, and ID/IG ratio, related to sp3 bonds in the DLC thin films, is directly attributed to some tribological properties including surface roughness, hardness, elastic modulus, friction coefficient, and contact angle. Some optical properties, such as transmittance, refractive index, and absorption coefficient, were examined after changing the thickness of DLC thin films. The optimal short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF) values were obtained for the significantly improved conversion efficiency (CE) from 4.92% to 5.35% in the 60 nm thick PECVD DLC ARC for DSSCs with hard and hydrophobic surfaces.

Optimizing the Microstructure, Mechanical, and Tribological Properties of Si-DLC Coatings on NBR Rubber for Its Potential Applications

Si doped diamond-like carbon (Si-DLC) films were deposited on nitrile-butadiene rubber (NBR), and the effects of deposition parameters on the mechanical and tribological properties of an Si-DLC top layer on NBR were investigated. Then, the sample with the best performance is selected to investigate its tribological behaviors and mechanism under different contact loads. The results show that the growth rate and the doped Si content are also decreased with increasing the CH4 flow rate. The Si atom exists in the form of Si-C bonds at low CH4 flow rate (≤40 sccm) and Si-C + Si-O-C bonds at high CH4 flow rate (≥60 sccm). Furthermore, the sp3 content increases monotonously, while the hardness and H3/E2 ratio firstly decreases and then increases. As a result, the friction and wear behaviors are in line with the change trend of the hardness. The lowest friction coefficient (~0.19) and a slight wear were achieved for the Si-DLC3 film under the relatively high load of 3 N. The tribological results indicate that the friction coefficient and wear increase monotonously with the increase of load, which is mainly attributed to the brittle fragmentation of films at a higher load, and thus a high strength and super toughness DLC films should be needed. Furthermore, the friction and wear behaviors of samples depend critically on its surface topography, and the wear is lower when the friction direction is parallel to the stripes.