EFFECTS OF FURNACE TEMPERATURE ON FORMATION OF MICROSPHERES BY POLYCARBOSILANE PARTICLES

A hollow microsphere was fabricated with a commercial polycarbosilane(PCS) polymer particle by the method of drop tower in a negative pressure and high temperature furnace.The effects of the furnace temperature on the formation of the microspheres were investigated at the given conditions,i.e.the PCS particle size is 110—118 μm,the gas in the furnace is Ar/He with 2∶1(in volume) ratio and the pressure of the gas is 0.09 MPa.Experimental results show that the production percentage,the diameter and the surface finish of microspheres increase at the beginning and decreases in the end with the increase of the furnace temperature from 200 ℃ to 1 000 ℃.The maximum mean production percentage is 73%,the largest mean diameter is 375 μm,and the best surface finish,i.e.the mean roughness R_(a)is 0.7 nm.The optimum furnace temperature for the formation of microspheres is about 700 ℃,the compositions of the microspheres is polycarbosilane,amorphous SiC and free carbon.