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In this investigation, the development of an empirical relationship to determine the porosity and microhardness of the coatings through low-pressure cold-sprayed (LPCS) aluminum alloy/alumina metal matrix composite (MMC) deposit. Spray parameters like temperature, standoff distance (SOD), and powder feed rate play an essential part in the determination of the coating effectiveness. In this study, 3 variables, 5 levels of central composite rotatable design (CCD) were used to decrease the total count of the experimentation. A mathematical model has been developed to evaluate the porosity and hardness of the coated samples along with LPCS spray parameters, and the model’s applicability was inspected by ANOVA. Utilizing response surface methodology, spray parameter optimization was carried out. The deposit developed by optimal spray parameters produces the lowest surface porosity of 3.31 vol.% and a higher hardness of 137.21 HV compared with other coated samples. It is validated through the response graph. As a result, the optimized parameters for aluminum alloy/alumina metal matrix composite (MMC) coatings via LPCS are 500 degrees Celsius, 10 mm SOD, and 20 grams/min powder feed rate.

Energy conservation and management have become critical industrial activities, since energy expenses account for a significant portion of production costs. This proactive strategy has had an effect on worldwide energy consumption trends. Integration of thermal barrier coatings into engine design is necessary to solve efficiency concerns, and this coating technology has the potential to increase engine power while lowering specific fuel consumption. In a similar line, biodiesel has been presented as a possible substitute to diesel since it is nontoxic and sourced from renewable energy sources. The present study aims to enhance the performance of a diesel engine via the use of a thermal barrier-coated piston that works on biodiesel mixes. Due to its outstanding thermal insulation qualities, yttria-stabilized zirconia is the preferred material for thermal barrier coatings. Brake thermal efficiency for B20E15 is about 4% better than diesel and for B20E05 and B20E15 is about 4.6% and 13.5% less fuel consumption. CO and HC emissions were reduced by 6% to 8% on average with the B20 blends. Biodiesel blends were compared to pure diesel in terms of performance and emissions, and the blend ratio was improved using a design of experiment tool.

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Case-hardening steels (EN36, 16MnCr5, and AISI 4140) are used in applications demanding good surface properties such as precision gears, shafts, and cam rollers. This study explores the formation of microcoatings to improve the surface characteristics of these steels using carbonitriding, which combines the merits of carburizing and nitriding to offer surfaces with enhanced hardness and wear resistance. Taguchi’s L18 orthogonal array is used for conducting the carbonitriding trials with replications. The effects of various carbonitriding parameters like carbonitriding time, temperature, and flow rate of ammonia are studied on the treated surface characteristics (Vickers microhardness, diffusion depth, and wear loss). A novel integrated approach of principal component-based grey incidence (PGI) that combines the merits of both principal component analysis and grey incidence theory is effectively used to select the optimal carbonitriding inputs (material substrate AISI 4140, carbonitriding temperature −835°C, carbonitriding time-40 min, and flow rate of ammonia 0.4 lit/min). Microscopic images related to diffusion depths are also analyzed. This study offers the necessary guiding principles for obtaining the desired surface coating on EN36, 16MnCr5, and AISI 4140 steels.