The main problem faced in the plasma spraying is the selection of optimum combination of input variables for achieving the required qualities of coating. This problem can be solved by the development of relationship between the process parameters (input power, stand-off distance and powder feed rate) and the coating quality characteristics (porosity,) by response surface methodology. This article highlights the use of response surface methodology by designing a three-factor five level central composite rotatable design matrix with full replication for planning, conduction, execution, and development of empirical relationship. Alumina coating was deposited on AZ31B magnesium alloy using atmospheric plasma spraying process by varying parameters such as power, stand-off distance and powder feed rate. Further, response surface methodology was used for the selection of optimum plasma spraying parameters to achieve desired quality of alumina coating

This paper reports the comparative evaluation of the corrosion behaviour of AZ31B magnesium alloy under immersion and potentiodynamic polarization test in NaCl solution at different chloride ion concentrations, pH value and exposure time. The specimens were exposed to immersion and polarization environments in order to evaluate their corrosion rates. Empirical relationship was established to predict the corrosion rate of AZ31B magnesium alloy. Three factors, five level, central composite rotatable design matrix was used to minimize the number of experimental conditions. Response surface methodology was used to develop the relationship. The developed relationship can be effectively used to predict the corrosion rate of AZ31B magnesium alloy at 95% confidence level for both the testing. This research work proves a better corrosion resistance of AZ31B magnesium alloy at the alkaline solution than the acidic and the neutral solutions, moreover, low corrosion rate was found at low concentrated solution and higher exposure time respectively

High-velocity oxy-fuel (HVOF) spray coating plays a major role in many surface treatment methods, which tend to improve erosion and corrosion resistance properties. HVOF is well known for its dense and high-quality coating ability. This is due to the less in-flight exposure time, which tends to have less oxide content because of its high-velocity properties. Among the number of process parameters, porosity and hardness are predominant factors while considering wear rate and corrosion behaviour analysis. The current study aims to optimise HVOF process parameters to obtain low levels of porosity and high hardness values in the WC-10Ni-5Cr coating sprayed on 35 Mo Cr steel. The flow rates of oxygen, LPG, coating powder feed rate and spray distance are selected in this study as these have a superior influence on the final condition of the coating. Statistical tools such as the design of experiments (DoE), analysis of variants and response surface methodology (RSM) were used to achieve the desired results. As per the result analysis, the oxygen flow rate has a higher effect on the porosity value and microhardness value of the coating.

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.

Surface treatment of engineering materials has recently become important for serviceable engineering components. Many techniques such as thermal and thermo chemical surface treatments have been used to develop surface characteristics of materials. Hardness is the most important property, which influences considerably service life characteristics of coatings. In this investigation, alumina coatings were deposited by atmospheric plasma spray technique under different levels of power, stand-off distances and powder feed rates. Empirical relationship was developed to predict the micro hardness of alumina coatings by incorporating the plasma spray process parameters. The input power and the stand-off distance appeared to be the most significant two parameters affecting the hardness of the coating among the three investigated process parameters. Further, correlating the spray parameters with coating properties enables the identification of characteristics regime to achieve desired quality of coatings

Alumina coating was deposited on AZ31B magnesium alloy using atmospheric plasma spraying process by varying parameters such as power, stand-off distance and powder feedrate. The porosity level of alumina coatings were evaluated by the digital image analysis method. An attempt was also made to develop an empirical relationship to predict the porosity level of alumina coatings. Three factors five level central composite rotatable design matrix was used to minimise the number of experimental conditions. Response surface methodology was used to develop the relationship. The developed relationship can be effectively used to predict the porosity level of alumina coatings at 95% confidence level. The results indicate that the input power has the greatest influence on porosity level of the coatings, followed by stand-off distance and powder feedrate.