Yazar "Ahmaida, Yousef Alamin A" seçeneğine göre listele

Listeleniyor 1 - 1 / 1
  • Küçük Resim
    Öğe
    INVESTIGATIONS OF TRIBOLOGICAL PERFORMANCES OF SUSPENSIONS FORMED WITH NANO SILVER AND EP ADDITIVES
    (2021-07) Ahmaida, Yousef Alamin A
    Wear of parts exposed to pressure and speed is the most important parameter affecting system efficiency in industrial applications. For this reason, it is of great importance to minimize the parameters affecting the wear. In order to reduce the temperature increase due to the increase in friction between materials under heavy load and high speed conditions, qualified lubricants developed with additives should be used. In addition to the performance of the obtained lubricants, the interaction with the load and speed parameters should also be analyzed. In this study, brass sliding bearing materials which are widely used in industrial applications were subjected to ball-on-plate wear tests in EP and AgNP reinforced lubricant conditions prepared at different concentrations. The sizes of silver nanoparticles used in wear experiments were characterized by TEM and particle size analysis, stabilization of silver nanoparticles was characterized by UV spectroscopy and Zeta potential measurement. The spreading performance of AgNP reinforced lubricants was analyzed by measuring the surface tension and wettability angles of liquids. The tribological performances of EP and AgNP reinforced lubricants were analyzed with friction coefficient, volume loss values, SEM and 3D topography images. The methodology determined for the tribological performance of lubricants is designed in 3 stages. In the first stage, the lubricants prepared by adding EP additives in different rates (5%, 10% and 15%) to ethylene glycol base oil were subjected to wear experiments under 20N load and 40 rpm speed conditions. It has been found that EG + 5% EP lubricant reduces friction coefficient by 52.19% and volume loss by 99.82% compared to dry conditions, and the optimum EP ratio was determined as 5% due to the higher effect rate compared to 10% and 15% concentrations. In the second stage, colloidal suspensions prepared by adding 1%, 5% and 9% rates AgNP to EG + 5% EP solution were subjected to wear experiments under 20N load and 40 rpm speed conditions. According to the results, the lowest friction coefficient (0.0276), volume loss (0.042 mm3) values and the best surface images were obtained at 1% concentration. In the third stage, the interaction of the lubricants prepared at the optimum EP and AgNP concentrations determined in the first two stages with the load and speed parameters was investigated by statistical analysis of the friction coefficient, volume loss and surface roughness parameters. Using EG, EG + 5% EP and EG + 5% EP + 1% AgNP lubricants, different load (10N, 20N and 30N) and speed (10 rpm, 25 rpm, 40 rpm) parameters, Taguchi' L9 fractional factorial experimental design was created. With the S/N analysis of the design, EG + 5% EP lubricant, 10N load and 40 rpm speed parameter combination was determined as the optimum test condition and EG lubricant, 30N load and 25 rpm speed parameters were determined as the worst test condition. The deformation mechanisms and surface form were investigated with SEM and 3D topography images obtained from the wear zones as a result of the experiments carried out under the best and worst experimental conditions. The effect ratios of the input parameters on the coefficient of friction, volume loss and surface roughness parameters were analyzed by ANOVA method. According to the ANOVA results, it was determined that the lubricant condition was the most effective parameter on the coefficient of friction (67.79%), volume loss (51.07%) and surface roughness (45.43%). The ability of the input parameters to explain the output parameters was analyzed with the R-Sq(adj) values obtained by ANOVA, and the fact that the obtained R-Sq(adj) values were greater than 70% showed that the experimental design was sufficient to explain the output parameters. The reliability of R-Sq(adj) values has been increased with the graphs and mathematical relations obtained by regression analysis.