Materials Science Forum Vol. 1115

Abstract: Aluminium and its alloys are becoming more widely used in engineering due to a growing need for lightweight metals. However, owing to boundary segregation and coarse dendritic grains, typical cast aluminium alloys have low hardness and strength, limiting their use in large-scale and complex-shaped applications. Many studies have shown that reinforcing aluminium alloy with nanoparticles synthesized by various chemical and physical ways improves these shortcomings, but these approaches are both expensive and potentially dangerous. Recycling aluminium scrap is also necessary to save energy and money. Therefore, this research aimed at production of high tensile strength and hardness from scrapped aluminium reinforced with synthetic nano particle and subjected to heat treatment. The elemental composition of aluminium alloy cast from scrap was analyzed using a Light Emission Polyvac Spectrometer, and gold nanoparticles were synthesized from aloe vera leaves. In creating a Metal Matrix Nano Composite, Al alloy was reinforced with gold nanoparticles at various percentages. At 450 °C, the reinforced Metal Matrix Nano Composite was hardened. The composites' hardness, tensile strength, and microstructural analyses were determined. The composites' grain structure demonstrated a uniform distribution of reinforcing phase of Al 6063 Alloy. The microhardness and tensile strength of the composites are influenced by the % weight proportion of AuNps and the heat treatment. After 3 percent and 6 percent weight of AuNps reinforcement were used, the microhardness/tensile strength of the reinforced sample rose by 22.4 Hv/58MPa and 24.7 Hv/80MPa, respectively, but when the composites were hardened, it climbed to 41 Hv/109 MPa and 45.5 Hv/125 MPa. After 3 percent and 6 percent weight of AuNps reinforcement were used, the microhardness/tensile strength of the reinforced sample rose by 22.4 Hv/58MPa and 24.7 Hv/80MPa, respectively, but when the composites were hardened, it climbed to 41 Hv/109 MPa and 45.5 Hv/125 MPa.

Abstract: In this study, effort was made to develop novel, cutting-edge composite materials consisting of conducting Al-CNTs and green synthesis silver nanoparticles (AgNPs). Spark plasma sintering (SPS) and very intense ball milling were used to develop the composites. The nanocomposites' microstructure, thermal and electrical conductivity were determined. Al-4%CNTs was refined into finer grains when AgNPs are present. The Al-4%CNTs+2%Ag.NPs composite produces a higher dislocation density because of the production of sub-grain. Al-AgNPs + CNTs can be used to make conductors with a high aspect ratio and lower contact resistance at the CNT junctions. It was established that enhanced electrical and thermal conductivity can be obtained using the developed AgNPs from sustainable materials to increase the dispersion of CNTs in Al for the production of high tensile conductors.

Abstract: Electrical tree is a topic that has been extensively studied in recent years. Electrical tree is considered a deterioration of the electrical insulator due to the high voltage field's distortion. Solid insulating materials used in high voltage applications, such as epoxy resin are widely employed due to their high dielectric strength and excellent mechanical properties. This research studies the effect of micro and nanoparticles of Al₂O₃ and SiO₂ on electrical tree inhibition in epoxy resin insulators. Electrical tree inhibition is achieved by incorporating micro and nanoparticles into the polymer material, which possess different properties. Following ASTM D 3756-97, the experiment is conducted with a constant 22 kV voltage and frequency of 50 Hz. Both Al₂O₃ and SiO₂ possess the ability to inhibit the growth of the electrical tree. Experimental results revealed that the addition of Al₂O₃ and SiO₂ to the epoxy resin affected the formation of electric trees. As the quantity of filler increases, fewer electric trees are produced. Additionally, It has an effect on the initial formation time of electric trees. The initial time of the electric tree with the addition of micro/nano(1/3) Al₂O₃ additives at a ratio of 0.1 wt% was 3.5 times longer when compare with pure epoxy resin.

Abstract: High-voltage electrical equipment insulation often uses composite materials like epoxy resin, cross-linked polyethylene, polyurethane, and silicone rubber as encapsulation. 3D printing technology offers a more efficient and cost-effective solution, producing intricate elements without cutting and casting. Research shows that 3D printed materials have comparable properties to polymer-based insulation, but further testing is needed to evaluate their resistance to harsh environmental conditions. This research investigates the arc resistance properties of 3D printed insulation materials for outdoor high-voltage applications, assessing their suitability for outdoor applications. The wet and dry arc resistance tests were performed in accordance with ASTM D495-99 and IEC-60587. The present work investigated three varieties of samples: polylactic acid, epoxy resin, and silicone rubber. The results of the tests reveal that polylactic acid test samples have average wet and dry arc resistance times of 2.5 hours and 1.4 seconds, which is less than silicone rubber and epoxy resin. Additional research is required to comprehend the behavior of arc formation in polylactic acid insulation materials for high-voltage 3D printing applications.

Abstract: Power transformers use mineral oil as an insulating liquid due to its excellent dielectric properties. However, mineral oil is a non-renewable resource and is toxic to the environment when leaked. The purpose of this research is to examine vegetable oil containing nanotitanium dioxide as a substitute for mineral transformer oil. Vegetable insulating oils are environmentally benign and have good breakdown voltage (BV) and high ignition points that can decompose naturally in the event of a leak. Nevertheless, the high viscosity of vegetable oil slows down the flow rate in the transformer cooling. To overcome this problem, the process of transesterification was used to produce soybean methyl ester (SBME). SBME is used as an insulating liquid including composite filler of titanium dioxide (TiO₂) nanoparticles. Electrical breakdown voltage (BV) tests were performed following ASTM D1816 standards. Results demonstrated that SBME has a greater BV than natural soybean oil. Also, the addition TiO₂ nanoparticles increases the BV of the SBME’s mixture. All cases of nanoparticle methyl ester (NPME) conducted in the experiments exhibited a BV higher than 28 kV which is well above the standard value.