Effects of the Ethyne Flow Ratio on Structures and Mechanical Properties of Reactive High Power Impulse Magnetron Sputtering Deposited Chromium-Carbon Films

Chromium-carbon films were deposited by utilizing reactive high-power impulse magnetron sputtering with different mixture ratios of ethyne and argon with a constant deposition total pressure while the deposition temperature, pulse frequency, duty cycle and average power of the chromium cathode remain the same. The microstructure and chemical bonding of the obtained films within different composition were compared. The results show that with the increasing ethyne ratio, the carbon content in films increases linearly with two slopes. Moreover, the microstructure of the deposited film changes from a dense glassy structure into a columnar structure, even a clusters structure. The sp2-C bonding in films decreases but the Cr–C bonding increases with decreasing the ethyne ratio. This reveals the main phase of films changes from a hydrogenated amorphous carbon phase into a glassy amorphous chromium carbide phase. Such changes of the microstructure and phase cause a large difference on the film hardness and elasticity.

Corrosion Resistance Synergistic Appraisal of Titanium-Impregnated Bisphenol A-Type Epoxy Duplex Coating System in Stimulated and Natural Marine Environments of Southeastern Coastal Area of China–Pakistan Economic Corridor

This research endeavor is aimed at developing a protective coating for marine service conditions of the southeastern coastal area of the China–Pakistan Economic Corridor. Bisphenol A-type epoxy-based protective coatings were prepared by impregnating exotic titanium metal microparticles into two different proportions, i.e., 5% and 10% ( w / w ). Film hardness measurement by pencil test, adhesion measurement by the crosshatch-tape test, chemical and heat resistance test, gloss measurement, natural exposure, and salt spray testing have demonstrated that Ti-enriched coatings have performed better than the virgin epoxy coating. Moreover, scanning electron microscopy has depicted more surface degradation. Fourier transform infrared spectroscopy has indicated higher mass loss and chain scission in the virgin epoxy coating than the Ti-enriched coatings. In addition, these Ti microparticles have filled up the cavities/imperfections, reduced cracking, promoted crosslinking during the curing, and cordoned-off passage of corrodents and moisture, thus improving epoxy resin coating features. These results have widened the scope of Ti-embedded epoxy coatings against atmospheric corrosion for highly corrosive marine sites.

Development and finishing technology of waterborne UV lacquer-coated wooden flooring

To develop a waterborne wooden flooring coating, the existing problems of the current waterborne coated wooden floorings were analyzed, and their corresponding solutions were considered. In this paper, based on the final effects of a novel waterborne UV wooden floor coating, the authors used a waterborne UV coating with different solids contents, as well as finishing and drying technology to treat the substrate with different tree species. According to the LY/T standard 1859-2009 (2009) and Q/YFL standard 0035-2018 (2018), the performance of the varnish film of the waterborne UV wooden floor coating was determined. The waterborne coating wooden flooring processes and effects of the varnish film were optimized to provide excellent performance. The performance of the varnish film and the developed waterborne coated wooden flooring met the standard requirements: the surface wear-resistance was less than or equal to 0.15 g/100r, the varnish film hardness was greater than or equal to H, the level of varnish film adhesion was less than or equal to 2, and the total volatile organic compounds was less than or equal to 20 µg/m3. This study provided a demonstration and basis for wooden flooring companies to develop a waterborne wooden floor coating.

A Molecular Dynamics Investigation of the Temperature Effect on the Mechanical Properties of Selected Thin Films for Hydrogen Separation

In this study, we performed nanoindentation test using the molecular dynamic (MD) approach on a selected thin film of palladium, vanadium, copper and niobium coated on the vanadium substrate at a loading rate of 0.5 Å/ps. The thermosetting control is applied with temperature variance from 300 to 700 K to study the mechanical characteristics of the selected thin films. The effects of temperature on the structure of the material, piling-up phenomena and sinking-in occurrence were considered. The simulation results of the analysis and the experimental results published in this literature were well correlated. The analysis of temperature demonstrated an understanding of the impact of the behaviour. As the temperature decreases, the indentation load increases for loading and unloading processes. Hence, this increases the strength of the material. In addition, the results demonstrate that the modulus of elasticity and thin-film hardness decreases in the order of niobium, vanadium, copper and palladium as the temperature increases.

Wood coating dust emission in the Malaysian furniture industry: A case study

The objectives of this study were to evaluate the current dust extraction efficiency used in the Malaysian furniture industry and also the effectiveness of using engineered nanoparticle (ENP)-added coatings to reduce dust emission in the wood finishing operation. This study was in response to the enforcement of the Clean Air Regulation (2014), which requires significant improvements in the air quality and the work environment in the wood-based industry in Malaysia. A series of sanding experiments with different abrasive grit sizes and different coating types were conducted to determine the dust emission levels. The results suggested that higher capture velocity of 30 m/s was necessary to effectively capture the wood coating dust emitted. Further, ENP-added wood coatings did not differ markedly from conventional coatings with regard to dust emission characteristics. The study also revealed that total dust concentration had an inverse relationship, while the amount of finer dust particles was linearly related to the coating film hardness. Therefore, to comply with the Clean Air Regulation, the Malaysian furniture industry needs to significantly improve its dust extraction system.

Accurate estimation of DLC thin film hardness using genetic programming

In the current research, diamond-like carbon thin films are deposited on silicon substrates by plasma-enhanced chemical vapor deposition. The effect of argon-C2H2 flow rate, hydrogen flow rate and deposition temperature on the thin film hardness is investigated. Morphology of the DLC films is investigated by scanning electron microscopy and atomic force microscopy, while the nano-hardness is investigated using nanoindentation. Raman spectroscopy is used for the characterization of the structural properties of the film. A metamodel of the DLC deposition process with argon- C2H2 flow rate, H2 flow rate and deposition temperature as the regressor variables and coating hardness as the response is built by using a novel symbolic regression approach. A state-of-the-art machine learning approach - genetic programming (GP) - is used for the symbolic regression. By carefully evaluating the performance of the current GP metamodel against a classical RSM (response surface methodology) metamodel, it is seen that the GP significantly outperforms RSM.