Preparation And Investigation On The Properties Of High Thermal Conductivity Mica Tape Tongma Epoxy Adhesives With ZnOw

As the main insulation of high-voltage motor, the performance of mica tapedetermines the stability of the motor. With the increase of motor capacity, it has ahigher request in the thermal properties and mechanical properties of mica tape.In this paper, traditional tong-ma epoxy adhesive was used as the original glue,and then the glue was doped with zinc oxide whisker（ZnOw） as the main filler,combination with the nano aluminum oxide（Al₂O₃） or boron nitride（BN）, inorder to improve the performance of mica tape. In addition, the surface activationtreatment of ZnOw was done and the changes of the performance of mica tapedoped with treated ZnOw was investigated.The study on the surface activation treatment of ZnOw showed that the besttype was KH570, and the optimal usage was2wt%. The mica adhesive dopedwith ZnOw was prepared, and the thermal conductivity, mechanical properties,dielectric properties of different doping amount mica tape were investigated.Experimental results showed that the optimum addition content of treated ZnOwwas10vol%, the performance index of mica tape was listed as follow: theconductive coefficient was0.29W/m·K, the transverse bending strength was248MPa, the longitudinal bending strength was256MPa, the dielectric strengthwas41.68MV/m, the volume resistivity was4.19×10¹³ m. Moreover, twodifferent methods of the mica tape adhesive doped with hybrid fillers werestudied, one of them was Al₂O₃and ZnOw, the other was boron nitride andZnOw. The effects of doping ratio and other factors on the mica glue wereanalysed, finally we obtained two excellent formulae. The first was that the totalfraction was25vol%, the volume fraction ratio of ZnOw and Al₂O₃was1:4,dispersion speed was2500r/min, the conductive coefficient was0.256W/m·K.The other was that the total fraction was20vol%, the volume fraction ratio of ZnOw and BN was1:2, dispersion speed was2500r/min, the conductivecoefficient was0.256W/m·K, and it had higher bending strength than the first one.The thermal conductivity model of mica glue doped with ZnOw was studied bycomparing the calculated data with the experimental data, a modified model wasobtained on the basis of Maxwell model, which could be similar to the actualdata.