Research on hydrophobicity treatment of aluminum nitride powder and the fabrication and characterization of AlN/PTFE composite substrates

A study on fabrication and characterization of different filler ratios AlN/ PTFE composite substrates was described. Phenyltrimethoxysilane (Z6124) was used to modify AlN ceramic powder. The contents of Z6124 were 0.8, 1.0, 1.2, 1.4, 1.6 wt%, respectively. The infrared spectroscopy, microstructure, contact angle and the pH changes in water of AlN ceramic powder were investigated in detail. The results revealed that 1.0 wt% Z6124 modified AlN ceramic powder exhibited the largest contact angle (θ = 148.4°), obvious coupling agent characteristic peak, and excellent water resistance. Next, 1.0 wt% Z6124 modified AlN powders were used to manufacture AlN/PTFE composites, and the contents of AlN ceramic filler were 25, 30, 35, 40, 45, 50 and 55 wt%, respectively. The effects of AlN ceramic content on the microwave dielectric properties, water absorption and thermal conductivity of AlN/PTFE composite substrates were systematically investigated. When the content of filler was 45 wt%, composite substrates exhibited reliable dielectric constant (ε_r = 3.38), acceptable dielectric loss (tan δ = 0.006) and excellent temperature coefficient of dielectric constant (− 32.6 ppm/°C), lower water absorption (0.056%) and high thermal conductivity (0.957 W/m K).