发泡剂对空心石英玻璃微球结构的影响

空心玻璃微球因具有低密度、高强度、耐高温等优点而被广泛研究。采用喷雾造粒法与粉末法相结合,掺入发泡剂,以射频等离子体作为热源制备空心石英玻璃微球,研究了SiC、CaSO₄、CaCO₃三种发泡剂对制备空心石英玻璃微球的影响。结果表明,通过喷雾造粒法将发泡剂与SiO₂充分混合形成粗坯颗粒,再利用射频等离子设备对粗坯粉末进行高温烧结,得到空心石英玻璃微球。其中CaSO₄、CaCO₃发泡剂效果较差,所产生的气体难以留在玻璃微球内部形成中空气泡;而SiC发泡剂效果最好,在射频等离子烧结过程中产生气体,被玻璃液包裹形成空心结构,得到的玻璃微球平均真密度为1.799 5 g/cm³。选用菲利华石英块状疏松体作为SiO₂原料,当m(SiO₂)∶m(SiC)∶m(H₂O)为100∶3∶300时,可制备出平均真密度为0.72 g/cm³的空心多孔石英玻璃微球。

Effect of Foaming Agent on Hollow Structure of Quartz Glass Microspheres

Hollow glass microspheres have been widely studied for their low density,high strength and high temperature resistance.Hollow structure of quartz glass microspheres(HSQGM)were prepared by spray granulation method combined with powder method,with the addition of foaming agent and radio frequency plasma as heat source.The effects of SiC,CaCO₃ and CaSO₄ foaming agents on the preparation of HSQGM were investigated.The results show that the foaming agent and silica are uniformly mixed to form coarse particles by spray granulation method,and then HSQGM are obtained by high temperature sintering of coarse powder by radio frequency plasma equipment.Among them,the effects of CaSO₄ and CaCO₃ are poor,and the generated gas are difficult to keep inside the glass microspheres to form hollow bubbles,while the effect of SiC is the best,which generates gas inside the glass microspheres in the process of radio frequency plasma sintering and is wrapped by liquid glass to form hollow structures.The average true density of the obtained glass microspheres is 1.7995 g/cm³.In addition,Feilihua bulk loose quartz is selected as raw material for SiO₂and the HSQGM with an average true density of 0.72 g/cm³ are obtained when the mass ratio of SiO₂,SiC and H₂O is 100∶3∶300.