二氧化锰对C-Al材料物相和显微结构的影响  

Influence of manganese dioxide on the phase composition and microstructure of C-Al materials

作　　者：魏军从[1,2] 孙加林[1] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]河北联合大学河北省无机非金属材料重点实验室,唐山063009

出　　处：《北京科技大学学报》2013年第8期1046-1052,共7页Journal of University of Science and Technology Beijing

摘　　要：为了避免添加铝粉的碳复合耐火材料在热处理过程中生成易水化产物Al4C3和AlN,本文研究了MnO2对C-Al材料物相和显微结构的影响.实验以鳞片石墨、金属铝粉和MnO2细粉为主要原料,以酚醛树脂为结合剂,分别经不同温度下埋石墨粉烧成.用X射线衍射分析试样物相,用扫描电镜观察试样显微结构,并研究了二氧化锰的综合热分析曲线.发现在不加MnO2的C-Al材料中,铝粉先生成粒状碳化铝,然后向纤维状氮化铝和氧化铝转化.在C-Al材料中加入MnO2后,由于MnO2逐渐释放出氧气,铝粉直接被氧化成氧化铝,继而生成锰铝尖晶石,避免了Al4C3和AlN形成;生成的氧化铝在800～1200℃以粒状为主,1400℃氧化铝以纤维状为主,1600℃生成了发育完全的柱状氧化铝.In order to avoid the generation of Al4C3 and AlN during heat treatment of carbon composite re- fractories with the addition of aluminum powder, this paper probes the effects of MnO2 on the phase composition and microstructure of C-Al materials. C-Al and C-Al-MnO2 specimens were prepared by using graphite flake, aluminium powder, and MnO2 fines as main starting materials, thermosetting phenolic resin as a binder, and being fired in a sag- ger filled with graphite powder at various temperatures. The phase composition and microstructure of the specimens were investigated by means of X-ray diffraction and scanning electron microscopy. Manganese dioxide was studied by thermogravimetric-differential thermal analysis. It is found that for C-Al materials without MnO2, Al powder first generates granular aluminium carbide, and then transforms to fibrous AlN and Al2O3. For C-Al materials with MnO2 addition, since MnO2 gradually decomposes with the evolution of oxygen, aluminum powder is directly oxidized to form Al2O3 followed by generating MnAl2O4 spinel. Thus, AI4C3 and AlN fail to form. The formed Al2O3 is present as granular at 800 to 1200℃, fibrous at 1400 ℃, and fully-developed prismatic at 1600 ℃.

关 键 词：耐火材料 氧化锰 相组成 显微结构 氧化铝 氮化铝 

分 类 号：TQ175[化学工程—硅酸盐工业]