Papers by Keyword: High Thermal Conductivity

Abstract: A thermally conductive silicone adhesive UB-5715 was prepared using vinyl silicone oil of medium viscosity, hydrogen-containing silicone oil and micron alumina powder. The results revealed that UB-5715 demonstrated superior thermal and mechanical properties. Specifically, its thermal decomposition temperature exceeded 400 °C, the thermal conductivity coefficient surpassed 1.80 W/m·K, the thermal resistance was under 12.0 °C·cm²/W, the shear strength reached achieved was over 5.00 MPa. Meanwhile, after being subjected to uHAST for 384 hours, thermal cycle for 1000 times and heat aging for 1000 hours respectively, UB-5715 still maintained its high thermal conductivity coefficient and mechanical properties. The thermal conductivity coefficient still exceeded 1.70 W/m·K, shear strength still surpassed 5.00 MPa, the tensile modulus remained below 100 MPa, the linear expansion coefficient was less than 160 ppm/°C, and its comprehensive performance met the reliability requirements for advanced packaging process substrates and heat dissipation cover assemblies.

Abstract: An efficient and low-cost aluminum alloy uniform solidification control technology, namely, air-cooled stirring rod (ACSR) process, has been developed for preparing large volume semisolid slurry. The semisolid slurry preparation process is connected with the die-casting machine to form multiple integrated intelligent rheological die-casting production lines for the efficient preparation of rheological die-casting of large-scale thin-walled aluminum alloys. At present, the ACSR process can produce 40 kg of large-volume semisolid slurry with a solid phase ratio of 25% to 35% within 30 s. This rheological die-casting process has been industrialized for the preparation of high-quality aluminum alloy large-scale thin-walled parts, such as new energy vehicles and 5G communications. Typical products produced by this process include heat dissipation housings for 5G communications, filter housings, antenna chassis and three-electric structural shell, end cover, and ABS system valve body for new energy vehicles. Compared with traditional die castings, aluminum alloy castings prepared by the new process not only have fine and spherical microstructures, good surface quality, and fewer internal pores but also enjoys more excellent mechanical properties and thermal conductivity.

Abstract: Due to the good physical properties of diamond, diamond/Al composites as a new generation electronic packaging material receive more and more attention. It is one of the greatest potential for the development of packaging materials. The paper on the diamond/Al composite materials research at home and abroad was summarized in detail.

Abstract: In this paper, α-Si₃N₄ was mixed with Y₂O₃ and MgO by ball milling. Spray granulation was adopted to fabricate spherical powder. The influence of the sintering temperature and the holding time on the thermal conductivity of the powder was studied. The results show that α-Si₃N₄ raw powder was transformed into β-phase after sintering. Spherical powder, of which the diameter is about 20 μm, was fabricated. Some compounds such as YMgSi₂O₅N, Y₄Si₂N₂O₇ and Y₂Si₃N₄O₃ were generated in the samples. The thermal conductivity of the pressed powder first increased then decreased with the sintering temperature rising, showing a maximum at 1800°C. Also the thermal conductivity first increased then decreased as the holding time getting longer, showing a maximum at a sintering time of 2 hours.

Abstract: Two types of Aluminum nitride (AlN) based ceramic nanocomposite with multifunctionality were investigated to improve machinability or electrical conductivity of AlN ceramics with high thermal conductivity. The AlN/BN nanocomposite was fabricated by hot-pressing AlN-BN composite powder, which was prepared by reducing and heating AlN particles containing a mixture of boric acid, urea and carbon. The nanocomposite containing 20 vol.% BN showed high strength, good machinability and relatively high thermal conductivity. On the other hand, the sintered AlN ceramics with CeO2 as an additive indicated high thermal conductivity and electric conductivity which is possible for electric discharge machining.

Abstract: A carbon foam with high strength and high thermal conductivity was prepared through the incorporation of nano-titanium particle into mesophase pitch precursor. Results show that titanium act as catalysts to accelerate the graphitization of carbon, promote more perfect and larger crystallites and enhance the conductive and mechanical properties. Test results reveal that titanium doped carbon foam (TDCF) has excellent compressive strength and high thermal conductivity, with highest values reaching 29.6 MPa and 117.8 Wm-1 K-1 for a titanium concentration of 12 wt% in the precursor materials. More compact struts and cell walls stacked by more uniform were observed by scanning electron microscope in carbon foam. Correlation between the content of dopant and the properties and microstructure of TDCF was discussed.