熔融石英晶化抑制与烧结性能

以＜0.040 mm的熔融石英粉体为原料,以五氧化二磷、氧化钛、氧化铝、硼酸、氮化硅为添加剂,试样成型压强为50 MPa,试样经1200 ℃、1300 ℃、1400 ℃、1500 ℃分别保温1小时烧成,对烧后试样进行抗折强度、气孔率、热膨胀率、XRD、SEM的测定,研究添加剂种类与含量对熔融石英晶化与烧结性能的影响.试验结果表明:对于1300 ℃烧结后的试样,添加剂氧化铝、氮化硅的引入对熔融石英的晶化具有明显的抑制作用.引入氧化钛、氮化硅的熔融石英试样的抗折强度较高,具有较好的烧结性能.引入五氧化二磷的试样烧结程度差,该添加剂具有促进熔融石英晶化的作用.

Research on Inhibiting Crystallization and Sintering Performance of Fused Quartz

Fused quartz granular (size＜40 μm) was used as raw material and phosphorous pentoxideBoric,titania,alumina,boracic acid,silicon nitride as additives.After being molded for 50 MPa and sintered at 1200 ℃,1300 ℃,1400 ℃,1500 ℃ for 1 h.Samples were tested in several aspects such as bending strength,apparent porosity,Thermal expansion rate (RT～1200 ℃),XRD and SEM.The effects of different additives and content on the sintering performances and crystallization of fused quartz are investigated.The results indicated that for samples sintered at 1300 ℃ for 1 h,effect of alumina or silicon nitride on inhibiting crystallization of fused quartz was obvious.Samples with titania or silicon nitride possess higher bending strength and sintering performances.Samples with phosphorous pentoxideBoric display lower sintering performances,the additive promote crystallization of fused quartz.