Showing 2 results for Koohestani
Hedayat Gholami, Hassan Koohestani, Mehdi Ahmadi,
Volume 18, Issue 1 (March 2021)
Abstract
In this research, using impregnation method, spinel cobalt and copper ferrites nanoparticles are synthesized on the surface of hematite. Synthesized powders were characterized and examined by FTIR, XRF, XRD, FESEM, BET and EDS analysis and the dye degradation were investigated by UV-vis and AAS methods. Specific surface area increased especially in the sample containing cobalt, which indicates the precise of synthesis and the creation of high surface nano particles at hematite surface. The size of particles was in the nano scale and a good uniformity observed in the structure. The results indicated a significant increase in the catalytic ability of hematite nano composite after synthesis. Their catalytic capability investigated by the Fenton reaction with complete removal of methylene blue from the solution via UV-vis irradiation. The samples stability discovered to be excellent by the AAS method.
Mohammad Jafaripour, Hassan Koohestani, Behrooz Ghasemi,
Volume 18, Issue 4 (December 2021)
Abstract
In this study, aluminum matrix composites reinforced with Al2O3 and SiC nanoparticles, and graphene nanoplatelets produced by Spark Plasma Sintering (SPS) were studied. The microstructural and mechanical properties of the composites were evaluated by changing the amounts of the reinforcing materials. The SEM images showed that the reinforcing particles were more distributed in the grain boundary regions. According to the results, the addition of alumina and SiC to the matrix caused an increase in the composite density whereas the composite density decreased by adding graphene nanoplatelets. The highest relative density of 96.3% was obtained for the composite containing 2 wt% Al2O3. The presence of the reinforcing particles increased the hardness of all the samples compared to the pure aluminum (39 HV). The composite containing 1 wt.% Al2O3, 0.7 wt.% SiC, and 0.3 wt.% graphene showed the highest hardness of 79 HV. Moreover, the plastic deformation of the specimens decreased and the slope of the plastic region increased by adding the reinforcing particles to the matrix.
