M. Kamran

Improvement in mechanical and thermal properties of unsaturated polyester- based hybrid composites

Polymer matrix composites are used in automobile, structure and aerospace industries due to their light weight and high strength. The present research has an aim to reinforce locally developed silica nanoparticles and glass fibers in unsaturated polyester to produce polymer-based hybrid composites. Composites were synthesized by hand lay-up method with 1, 2, 3 and 4 wt% of silica sand nanoparticles and glass fiber. Mechanical tests like tensile, impact and micro-hardness were performed on the obtained polymer hybrid composites. The results of mechanical properties of the hybrid polymer matrix composites revealed an increasing trend. The SEM analysis was performed on the developed and fractured tensile testing samples. The SEM analysis showed the presence of silica nanoparticles in the samples and pulling action of fibers were seen under fractured tensile tests. The pulling actions of fibers from polymer matrix delayed the fractured mechanism and enhanced the mechanical properties. Silica nanoparticles filled the cavities generated during tensile test and extensive enhancement was revealed in tensile as well as impact energy. Toughness of the hybrid composite was also enhanced as a result. The thermal properties of the hybrid polymer composites were analyzed using thermogravimetric analysis. Thermal stability of the composite has been marginally increased with increasing wt% of reinforcement.

Evaluation of Surface Preparation Techniques for Steel Substrates Prior to Coating Application

The performance of organic coatings on steel substrates is strongly affected by substrate cleanliness and anchor patterns. During present research work, Surface pre-treatments were applied to remove contaminants from steel surfaces. Electrochemical Impedance Spectroscopy (EIS) was used to characterize such surfaces in terms of electrochemical parameters to find out the extent of activeness of prepared surfaces, and electrochemical processes are modeled into corresponding electrical equivalent circuits (EECs). Surface roughness parameters were evaluated to find out the extent of mechanical interlocking between prepared surface and the coating to be applied over it. The optimum surface preparation technique prior to application of organic coating was characterized.

Investigating the Pitting Resistance of 316 Stainless Steel in Ringer's Solution Using the Cyclic Polarization Technique

Corrosion rate, corrosion potential and susceptibility to pitting corrosion of a metal are measured using cyclic polarization Direct Current (DC) electrochemical technique. The aim of the present research is to investigate the pit nucleation resistance of polished, ground and passivated surfaces of 316 stainless steels in Ringers solution. The electrochemical cyclic polarization results showed that polished surface gave better pitting resistance as compared to ground surface. It was also observed that passivation treatment gave better pitting resistance to both polished and ground surface of 316 stainless steels in Ringers solution.