Study on dielectric properties of BADCy/Ni_0.5Ti_0.5NbO₄ composites fabricated by freeze casting combined with vacuum assisted infiltration process

Bisphenol-A dicyanate ester resin (BADCy)/Ni_0.5Ti_0.5NbO₄ composites, within which Ni_0.5Ti_0.5NbO₄ and BADCy are continuously directionally distributed, were fabricated using freeze casting combined with vacuum assisted infiltration process. The control of the microstructure of porous Ni_0.5Ti_0.5NbO₄ preforms was systematically studied. Effect mechanisms of the preform microstructure on the dielectric properties of the BADCy/Ni_0.5Ti_0.5NbO₄ composites were firstly researched. Results show that cold source temperature and sintering temperature have significant influences on the microstructure of porous Ni_0.5Ti_0.5NbO₄ preforms. The microstructure of the preforms further greatly affects the dielectric constant and the loss of the BADCy/Ni_0.5Ti_0.5NbO₄ composites. Due to the excellent dielectric properties, this kind of composites possesses a wide application in printed circuit board (PCB) field. This study is also very helpful for the design and fabrication of this kind of composites.