摘要
以高纯绿SiC和Si粉为原料,用630t摩擦压力机成型为600mm×400mm×90mm的坯体,经远红外干燥后,以城市煤气为燃料,在20m3梭式窑中分别于1420和1500℃隔焰氮化烧成,对烧后Si3N4-SiC试样中心和边缘部位的理化性能(包括抗冰晶石侵蚀性能)和显微结构进行了检测和分析。结果表明:1)反应烧结Si3N4-SiC耐火材料中Si3N4的形成、分布和完全氮化等受诸多因素影响;要想使制品(尤其是尺寸较大的制品)的氮化比较完全,提高氮化烧成温度是非常有效的途经;2)制品中Si3N4分布不均匀:中心部位Si2N2O和游离Si的含量均较边缘部位的高,显气孔率也比边缘部位高约1%～2%;3)随着温度的升高,不可避免地出现Si的迁移,从而导致最终制品中Si3N4的分布不均匀,但这是否会影响制品的使用性能,尚需进一步研究。
Si3N4 -SiC specimens were prepared using high pure green SiC and Si powder as starting materials, pressed into 600 mm ×400 mm ×90 mm,nitridized at 1 420 and 1 500℃ in 20 m3 shuttle kiln with city coal gas as fuel,after far-infrared drying. Physical properties and chemical composition （including corrosion resistance to cryolite）and microstructure of the inner and outer parts in Si3N4 -SiC specimens were determined and analyzed. The results show that. 1 ） Formation, distribution and nitridation of Si3N4 in sintered Si3 N4 -SiC specimens are affected by many factors. Increasing firing temperature is more effective to solve fully nitridation of products,especially big size products. 2） Distribution of Si3N4 in Si3N4 -SiC specimens is ununiform. The contents of Si2N2O and free Si in the inner part are higher than in the outer part. Apparent porosity in the inner part are 1% -2% higher than that in the outer part. 3） Si movement is inevitable with the temperature increasing,which caused ununiform distribution of Si3N4 in products. Further study is necessary whether this will affect the performance of Si3N4 -SiC products or not.
出处
《耐火材料》
CAS
北大核心
2009年第3期175-178,共4页
Refractories
关键词
反应烧结
烧成温度
SI3N4-SIC
耐火材料
氮化烧成
铝电解槽
Reactive sintering, Firing temperature, Silicon nitride - silicon carbide refractories, Nitridation firing,Aluminum electrolysis cell
