Hongbin Lu

Synthesis of Epoxy Resin Based on Biphenyl Structure for Application in Carbon Fiber-Reinforced Composites

A series of epoxy resins based on biphenyl structure were prepared to produce heat-resistant carbon fiber-reinforced composites. The molecular weight of the epoxy resin was characterized by gel permeation chromatograph (GPC). The thermal properties of the cured polymers were evaluated with dynamic thermal mechanical analysis (DTMA) and thermo gravimetric analysis (TGA). Results showed that the cured polymer exhibited a higher glass transition temperature (Tg) of 192.9°C and a better thermal stability by introducing biphenyl structure. Moreover, the carbon fiber-reinforced composites containing biphenyl structure showed high tensile and shear properties at 120°C. Such properties make the resin highly promising for heat-resistant aluminum conductor composite core (ACCC) applications.

Fabrication of Ni/SiC composite powder by mechanical alloying and its effects on properties of copper matrix composites

Abstract Composite powders of Ni-30SiC (vol.%) were fabricated by mechanical alloying. Scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy were used to analyze the microstructure, morphology and composition of the composite powders. Mixed powders and Ni coating layers on the surface of SiC particles were investigated. The Ni/SiC composite powder with the optimal coating was mixed with Cu powder to manufacture Cu matrix composites by powder metallurgy, and the relative density, hardness and electrical resistivity of the composites were measured. The results show that the Ni coating becomes increasingly prominent and that the mixed powders become increasingly homogeneous as the ball-milling time increases; however, an excessively long milling time has a negative impact on the coating. The milling speed also has an important effect on the coating. Too high of a rotational speed quickens the rate of work hardening of the coating layer, which causes the coating layer to fall off. When the milling time is 20 h, the milling speed is 300 r min−1 and the ball to powder weight ratio is 10 : 1, the SiC particles are well coated by Ni and the powders are uniformly mixed. The properties of the copper matrix composite processed with the optimal milling parameters are effectively improved.