SiO_2加入量对Si_2N_2O结合SiC试样相组成与显微结构的影响

Influence of SiO_2 addition on phase composition and microstructure of Si_2N_2O bonded SiC

以纯度均〉97％的磨料级黑SiC、硅粉和SiO2粉为原料，加入临时结合剂，混练15～20min后，在油压机上压成125mm×25mm×25mm的试样，再将干燥后的生坯在高纯氮气中于1450℃10h氮化烧成后，制成了SiO2加入量（w）分别为0、4％、6％、8％、10％的Si2N2O结合SiC试样，以研究SiO2加入量对材料相组成与显微结构的影响。结果表明：随着SiO2细粉加入量的增加，试样基质中的Si2N2O生成量逐渐增加，Si3N4量逐渐降低；试样的整体结构变得越来越致密，孔洞部位Si2N2O晶体的发育越来越趋于完全。

Si2N2O bonded SiC specimens with 0,4% ,6% ,8% and 10% SiO= respectively were prepared with abrasive black SiC,silicon powder and SiO2= powder （their purities are all more than 97%） as starting materials, adding temporary binder, pressing into the specimen with the size of 125 mm ×25 mm ×25 mm,drying,and firing at 1 450 ℃ for 10 h in high purity nitrogen. Influence of SiO2 additions on phase composition and microstructure of Si2N2O bonded SiC specimens was researched. The results show that with the increase of SiO2 powder addition,Si2N2O amount in matrix increases,Si3N4 decreases, integral structure of specimen becomes dense,and Si2N2O crystal in pore space tends to perfect development.