Effect Factors of Heat Transfer Coefficient Between Hollow Glass Microsphere and Furnace Atmosphere

In order to achieve an effective control of the heat transfer coefficient(h_q)(between) microsphere and furnace atmosphere in the fabrication of hollow glass microsphere by sol-gel technology,the effects of component percentage,temperature and(total) pressure of gas mixture on h_q are studied.Further,the influences of diameter and wall thickness of hollow glass microsphere on h_q are also investigated.The results show that in the range of component percentage,temperature and pressure of gas mixture commonly used in the fabrication of hollow glass microsphere by sol-gel technology,the temperature and total pressure of gas mixture and the wall thickness of hollow glass(micros)phere have little influence on h_q,but h_q significantly increases with the volume fraction of helium in the furnace atmosphere and significantly decreases with increasing of microsphere diameter.