Highly-oriented polycrystal 3C-SiC bulks were ultra-fast fabricated via halide chemical vapor deposition (CVD) using tetrachlorosilane (SiCl₄) and methane (CH₄) as precursors. The effects of deposition temperature (T_dep) and total pressure (P_tot) on the orientation and surficial morphology were investigated. The results showed that the growth orientation of 3C-SiC columnar grains was strongly influenced by T_dep. With increasing T_dep, the columnar grains transformed from - to -oriented. The arrangement of -oriented columnar grains was controlled by P_tot. Lotus-, turtle-, thorn-, and strawberry-like surface morphologies were naturally contributed by different arrangements of -oriented grains, and the deposition mechanism was discussed. The wetting behaviors of CVD-SiC samples by molten aluminum were also examined at 1173 K in a high vacuum atmosphere.

Bipolar plates in proton exchange membrane fuel cells (PEMFCs) are confronted by the dilemma of low contact resistance and high corrosion resistance; this study aimed to simultaneously satisfy these dimensions in a harsh environment. Using thick multilayer coatings can improve the corrosion resistance, but the contact resistance would be largely compromised. To address this challenge, we propose compatible tantalum/titanium-based coatings on 316L stainless steel (SS316L) as bipolar plates for PEMFCs. With the transition layer, the optimal TaN/(Ta,Ti)N/TiN/Ti coating exhibits an ultralow corrosion current density of 0.369 μA·cm⁻² (at +0.6 V vs. SCE) and a contact resistance of 6 mΩ cm² at 138 N/cm² after 5 h of potentiostatic polarization, both of which meet the standard of the U.S. Department of Energy. Electrochemical impedance spectroscopy (EIS) and an equivalent electrical circuit model further elucidated that TaN/(Ta,Ti)N/TiN/Ti coating significantly impedes the oxidation reaction and dissolution of metals and provides good protection for the SS316L.

In this study, we demonstrated the chemical vapor deposition (CVD) of vertically standing molybdenum disulfide (MoS₂) nanosheets, with an unconventional combination of molybdenum hexacarbonyl (Mo(CO)₆) and 1,2-ethanedithiol (C₂H₆S₂) as the novel kind of Mo and S precursors respectively. The effect of the distance between the precursor’s outlet and substrates (denoted as d) on the growth characteristics of MoS₂, including surface morphology and nanosheet structure, was investigated. Meanwhile, the relationship between the structure characteristics of MoS₂ nanosheets and their catalytic performance for hydrogen evolution reaction (HER) was elucidated. The formation of vertically standing nanosheets was analyzed and verified by means of an extrusion growth model. The crystallinity, average length, and average depth between peak and valley (Rz) of MoS₂ nanosheets differed depending on the spatial location of the substrate. Good crystalized MoS₂ nanosheets grown at d = 5.5 cm with the largest average length of 440 nm, and the highest Rz of 162 nm contributed to a better HER performance, with a respective Tafel slope and exchange current density of 138.9 mV/decade, and 22.6 μA/cm² for raw data (127.8 mV/decade and 19.3 μA/cm² for iR-corrected data).

Hard coatings, such as transition metal nitrides, have been widely applied to improve the mechanical properties and tribological performance of cutting tools. The coatings in various multilayered or gradient structures have been designed to meet the demands of more severe service environments and more precise processing requirements. In this work, TiN/TiSiN coatings in several gradient and multilayered structures were deposited on cemented carbides by cathodic arc ion plating using Ti and TiSi alloy targets. The modulation period (Λ) of the multilayer gradually varies with thickness, ranging from 6 to 46 nm. The gradient multilayer coatings consist of a nanocrystalline-amorphous composite with compact growth. The coating with a modulation period first increasing and then decreasing has the highest hardness of 38 GPa, and the maximum residual compressive stress of −2.71 GPa, as well as the minimum coefficient of friction (COF) and wear rate. Gradient and multilayer structures moderate the brittleness caused by the presence of amorphous SiNx phase and optimize the mechanical properties and tribological performances of the coatings.

TaN/(Ta/Ti)/TiN multilayer films at various target to substrate distances (d_ts), composed of hexagonal TaN, (t-Ta/fcc-Ti) and fcc-TiN with a sandwich structure, were prepared via multi-arc ion plating. With increasing d_ts, the deposition rate of the films first increased and then decreased, and the average grain size increased from 11.9 to 13.9 nm and then decreased to 10.4 nm. The TaN/(Ta/Ti)/TiN multilayer films have a high ratio of hardness to elastic modulus (H/E*) and H³/E*² ratios, displaying an outstanding level of both hardness and toughness compared with Ta-related films. The nano-multilayer TaTi interlayers inhibited the columnar structure and prolonged the corrosion diffusion path by increasing stable interfaces. The TaN/(Ta/Ti)/TiN multilayer film at d_ts = 220 mm exhibited comprehensive properties, including a high hardness of 25 GPa, strong adhesion strength of 68 N, low coefficient of friction of 0.41, low wear rate of 2.7 × 10⁻⁶ mm³(mN)⁻¹ and great corrosion resistance in 3.5 wt% NaCl solution, showing promising application as a protective coating.