Wednesday, 09 October 2019 06:13

Graduate student, Zulekha Ali Abdullah optained a master's degree from the Department of Applied Sciences at the University of Technology for her thesis entitled " Preparation of (Al) Metal Matrix Composites Reinforced with Coated Ceramic Particles ", which was held in the hall of the deceased Dr. Abdul Muttalib Ibrahim Sheikh..

The discussion committee consisted of  Prof.Dr. Muzaffar Ali Mohammed as a President and Prof.Dr. Suad Hamed Laibi and Dr. Ahmed Star Jabbar as members and Dr. Mufid Abdul Latif Abdul Jalil as a supervisor.

      This studying included  Metallic coatings which were used to modify the interfacial bonding of SiC particles reinforcement of Al matrix. Electroless deposition method has been used to deposit Ni-3%P coating on SiC particles by using electroless nickel (EN) bath to form core shell. In EN bath of a constant pH 8, the influence of SiC particle size (10, 80µm), agitation method (magnetic stirrer, ultrasonic), bath temperature (50, 60, 70 and 80°C), deposition time (5, 10, and 15 min) on Ni-P coating uniformity were studied. The morphology of the deposit Ni-P was studied by optical microscope, scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS).

        Electroless nickel results have showed that bath parameters and agitation methods have great influence on coating deposition, best uniform Ni-P deposition was achieved for 80µm SiC particles in 70°C bath temperature for 15 min agitated by magnetic stirrer.

        Best EN conditions were carried on in the process of preparing Ni coated SiC, which were used as reinforcement in aluminum matrix composites (AMCs). The influence of uncoated/ coated SiC reinforcement with different percentages (5, 10, 15, and 20%), sintering processing time (2 and 4h)  and temperature (580 and 620°C), on AMCs mechanical properties (micro hardness, wear resistance, indirect tensile test) and Al-Ni intermetallics examination via X-Ray diffraction (XRD) were studied.

        XRD indicated the formation of few Al-Ni intermetallics phases (AlNi3, Al3Ni2, and AlNi) in AMCs with coated SiC reinforcement after sintering, and the absence of Al4C3 formation.

        Mechanical properties for Ni coated SiC/AMCs showed great improvement over those with uncoated reinforcement AMCs and pure Al; those also varied depending on sintering conditions.

        The highest values for hardness and wear resistance were achieved by 20% and 15% coated SiC/AMCs, respectively both at sintering conditions 580°C for 4h. 10% coated SiC/AMCs sintered at 620°C for 2h resulted in the highest tensile strength.

 

 

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