Fabrication of Al2O3/ZnO and Al2O3/Cu Reinforced Silicone Rubber Composite Pads for Thermal Interface Materials

Thermal interface materials (also known as thermal pads) are widely used as a crucial part to dissipate heat generated in miniaturized and integrated electronic components. Here, we systematically investigated the effects of small ceramic and metallic powders in rubbery thermal composite pads with a high content of aluminum oxide filler on the thermal conductivity of the composite pads. We optimized the compositions of aluminum oxide fillers with two different sizes in a polydimethylsiloxane (PDMS) matrix for rubbery composite pads with a high thermal conductivity. Based on the optimized compositions, zinc oxide powder or copper powder with an average size of 1 μm was used to replace 5 μm-sized aluminum oxide filler to examine the effects of the small ceramic and metallic powders, respectively, on the thermal conductivity of the composite pads. When zinc oxide powder was used as the replacement, the thermal conductivity of the rubbery composite pads decreased because more air bubbles were generated during the processing of the mixed paste with increased viscosity. On the other hand, when the copper powder was used as a replacement, a thermal conductivity of up to 2.466 W/m·K was achieved for the rubbery composite pads by optimizing the mixing composition. SEM images and EDS mapping confirmed that all fillers were evenly distributed in the rubbery composite pads.

A Comparative Study of the Manufacturing of BPSCCO Superconducting Wire with TiO2 Dopants

Bi-Pb-Sr-Ca-Cu-O (BPSCCO) superconductors are recognized as a projectable high-temperature superconductor for high-efficiency electrical applications. The addition of Ti enhances the formation of the Bi-2223 phase from the BPSCCO superconductor. The process of producing BPSCCO superconducting materials with TiO2 dopants is performed by the solid-state process and the production of wire rolling, consisting of bismuth (III) oxide powder (Bi2O3 = 99%), Strontium Carbonate powder (SrCO3 = 99%), Calcium Carbonate powder (CaCO3 = 99%), Copper Oxide powder (CuO2 = 99%), Lead Oxide powder (PbO2 = 98%) Bi: Pb: Sr: Ca: Cu ratio: 1.6: 0.4:2:2:3 doped by 1 %wt Titanium Oxide powder (TiO2 = 98.5%). The variables used in this study were the comparison of the sintering method at 860°C for 24 hours and 820 °C calcination for 20 hours, and 850°C sintering for 20 hours. The superconductor characterization was tested through the X-Ray Diffraction (XRD) test, Scanning Electron Microscopy (SEM), and Resistivity test. XRD test results showed the formation of Bi2Sr2CuO6 and Bi2Sr5Cu3O16 phase. SEM results showed an increase in grain size. The resistivity test results showed that all samples formed critical temperatures, 9.6 and 9.5K respectively.