Fiber-reinforced resin matrix composites are widely used in organic printed circuit boards (PCBs). However, conventional glass fiber reinforced epoxy resin (EP) matrix composites suffer from low thermal conductivity and poor electrical properties. Herein, to coordinate the thermal and electrical properties of the composites, a novel c-BN/EP/Si 3 N 4 composite for PCBs was prepared by hot-pressing moulding method by selecting Si 3 N 4 fibers instead of glass fibers and introducing nano cubic boron nitride (c-BN) particles as filler at the same time. Combined with Si 3 N 4 fibers, nano c-BN filler with suitable content can further improve thermal transfer capacity and limit the volume shrinkage of EP during curing, resulting in the decreased porosity and strong interfacial bonding between Si 3 N 4 fibers and EP. When c-BN content is 20 wt%, the c-BN/EP/Si 3 N 4 composite shows excellent in-plane thermal conductivity (2.124 W m −1 K −1 ), low coefficient of thermal expansion (4.34 ppm K −1 ) and excellent breakdown strength (55.71 kV mm −1 ). Therefore, the c-BN/EP/Si 3 N 4 composites have a potential application in the field of organic PCBs substrates.
C/C-BN-SiC composite was prepared by ceramic slurry infiltration combined with resin impregnation and carbonization, and the matrix with continuous distributed self-healing phase was obtained. In this study, the kinetic characteristics and oxidation behavior of the composites with various h-BN/SiC ratios in the temperature range of 600∼1300°C were studied by combining the isothermal oxidation test with the kinetic model. The optimal h-BN/SiC ratio balances the thermal stability and fluidity of the oxidized product, which not only has high thermal stability and low oxygen permeability to acts as an oxygen diffusion barrier but also has a certain fluidity to seal defects.
In this study, with 2.5D needle punched carbon felt as reinforcement, hexagonal boron nitride (h-BN) was introduced through chemical vapor infiltration (CVI) and slurry impregnation (SI) methods, and then pyrocarbon was deposited through CVI to convert the BN-containing preform into carbon fiber reinforced carbon-boron nitride binary matrix composites (C/C-BN). The microstructure and mechanical properties of C/C-BN(P) composites prepared by SI combined with CVI were compared with those of C/C-BN(CVI) composites prepared by CVI. The tribological behavior of C/C-BN(P) composites containing different contents of h-BN fillers and C/C-BN(CVI) composites with and without heat treatment was investigated by the ball-on-disk technique in dry sliding conditions using GCr15 steel balls and Si 3 N 4 balls as sliding counterparts at two different sliding speeds (v = 0.2 and 0.8 m/s), and compared with the C/C composites used as a reference. C/C-BN(P) composites exhibit improved tribological behavior, which can be explained by the combined effect of SI and CVI on the microstructure and mechanical properties, leading to changes in the wear mechanism of the C/C-BN composites. The excellent reinforcement is attributed to the integrity structure of the C/C-BN(P), which can make the self-lubricating friction layer stably exist on the surface of the material and significantly reduce the friction coefficient and wear loss of the C/C-BN(P) composite. Furthermore, the mechanical and tribological properties of C/C-BN(P) composites can be adjusted by using different volume content of h-BN. The present work shows that C/C-BN(P) composites have wide application prospects as anti-friction and wear-resistant materials.
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