埋碳条件下氮化硅铁-刚玉复合材料的反应机理

Reaction Mechanism of Ferro-silicon Nitride-corundum Composite With Carbon Embedded

以热固型酚醛树脂为结合剂,在刚玉中分别引入质量分数为0、5%、10%、15%、20%、25%的氮化硅铁,制备出氮化硅铁-刚玉复合材料。结果表明:样品在埋碳气氛下于1 450℃保温24h处理后,常温耐压强度增加;添加氮化硅铁质量分数为15%的样品,耐压强度达到132MPa。氮化硅铁中部分Fe3Si转化成为Fe4N;热固酚醛树脂结合剂中部分残碳与氮气反应生成C3N4;氮化硅与刚玉发生固溶,生成Si5AlON7(Z=1)。氮化硅铁中的氮化硅与刚玉固溶形成Sialon。新形成的物相(Fe4N、C3N4和Si5AlON7)改善了样品的性能。

Specimens of ferro-silicon nitride-corundum composites were prepared with ferro-silicon nitride of 0.5%(in mass),10%,15%,20%,and 25%,respectively and thermosetting phenol resin.The cold crushing strength of the specimens was improved after being sintered at 1 450℃for 24 hwith carbon embedded.The cold crushing strength of the specimen with 15%ferro-silicon nitride-corundum is 132 MPa.The results show that some Fe3 Si from ferrosilicon nitride is converted to Fe4 N.The remaining carbon from thermosetting phenol resin turned into C3N4.Si5AlON7(Z=1)appeared due to the reaction between silicon nitride and corundum,indicating thatβ-Sialon is available under the condition of normal pressure.The properties of the composites could be enhanced due to the presence of the formed phases(i.e.,Fe4 N,C3N4and Si5AlON7).