Study on dielectric properties of BADCy/Ni0.5Ti0.5NbO4 composites fabricated by freeze casting combined with vacuum assisted infiltration process

Bisphenol-A dicyanate ester resin (BADCy)/Ni0.5Ti0.5NbO4 composites, within which Ni0.5Ti0.5NbO4 and BADCy are continuously directionally distributed, were fabricated using freeze casting combined with vacuum assisted infiltration process. The control of the microstructure of porous Ni0.5Ti0.5NbO4 preforms was systematically studied. Effect mechanisms of the preform microstructure on the dielectric properties of the BADCy/Ni0.5Ti0.5NbO4 composites were firstly researched. Results show that cold source temperature and sintering temperature have significant influences on the microstructure of porous Ni0.5Ti0.5NbO4 preforms. The microstructure of the preforms further greatly affects the dielectric constant and the loss of the BADCy/Ni0.5Ti0.5NbO4 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.