摘要
以电熔镁砂、α-Al_2O_3微粉、鳞片石墨、和炭黑为原料,制备低碳Mg O–Al_2O_3–C材料。通过改变原料混炼顺序来影响材料内原位尖晶石化反应,研究了原位尖晶石化反应对低碳Mg O–Al_2O_3–C材料结构与性能的影响。结果表明:试验温度下体系内固相反应、气–固反应均满足尖晶石生成的热力学条件。α-Al_2O_3微粉和炭黑经酚醛树脂造粒后以碳包覆Al_2O_3球体的形态存在材料中,体系内的尖晶石主要通过气–固反生成在包覆体表面,并阻碍Mg(g)向Al_2O_3球体内部扩散,导致1 400℃热处理后有Al_2O_3残余。尖晶石层有效地结合骨料与基质,提高了材料的力学性能。
Low-carbon MgO–Al_2O_3–C materials were prepared with fused magnesia,α-Al_2O_3,flake graphite and carbon black as raw materials.The effect of in-situ spinel reaction on the structure and properties of low carbon MgO–Al_2O_3–C materials was investigated.The results show that the solid-phase reaction and gas-solid reaction in the system at the test temperature satisfy the thermodynamic conditions of spinel formation.In the materials,the microstructure ofα-Al_2O_3 and carbon black changes into carbon-coated Al_2O_3spherical particles after pelleted by phenolic resin.The spinel in the system is mainly formed on the surface of the carbon-coated Al_2O_3 spheres via the gas–solid reaction,and hinders the diffusion of Mg(g)into the interior of the Al_2O_3 sphere,resulting in residual Al_2O_3 after heat treatment at 1 400℃.The spinel layer effectively combines the aggregate with the matrix to improve the mechanical properties of the materials.
引文
[1]李楠,顾华志.耐火材料学[M].北京:冶金工业出版社,2002:185.
[2]李红霞,刘国齐,杨彬.连铸用功能耐火材料的发展[J].耐火材料,2001,35(1):45-49.LI Hongxia,LIU Guoqi,YANG Shan.Refractories(in Chinese),2001,35(1):45-49.
[3]BAG M,ADAK S,SARKAR R.Study on low carbon containing MgO-C refractory:Use of nano carbon[J].Ceram Int,2012,38(3):2339-2346.
[4]LI Hongxia,LIU Guoqi.Current situation and development of refractories for clean steel production[J].China’s Refract,2013,22(3):1-6.
[5]WEI Guoping,ZHU Boquan,LI Xiangcheng,et al.Microstructure and mechanical properties of low-carbon MgO-C refractories bonded by an Fe nanosheet-modified phenol resin[J].Ceram Int,2015,41(1):1553-1566.
[6]廖宁.纳米碳源制备低碳铝碳耐火材料微结构和力学性能研究[D].武汉:武汉科技大学,2016.LIAO Ning.The microstructures and mechanical properties of nano carbon sources containing low-carbon Al2O3-C refractories(in Chinese,dissertation).Wuhan:Wuhan University of Science and Technology,2016.
[7]李红霞.耐火材料发展概述[J].无机材料学报,2018,38(2):198-205.LI Hongxia.J Inorg Mater(in Chinese),2018,38(2):198-205.
[8]HASHEMI B,NEMATI Z A,FAGHIHI-SANI M A.Effects of resin and graphite content on density and oxidation behavior of MgO-Crefractory bricks[J].Ceram Int,2006,32(3):313-319.
[9]LIU Zhaoyang,YU Jingkun,YANG Xin,et al.Oxidation resistance and wetting behavior of MgO-C refractories:effect of carbon content[J].Materials,2018,11(6):1-11.
[10]TRIPATHI H S,GHOSH A.Spinelisation and properties of Al2O3-MgAl2O4-C refractory:effect of MgO and Al2O3 reactants[J].Ceram Int,2010,36(4):1189-1192.
[11]SAKO E Y,BRAULIO M A L,ZINNGREBE E,et al.Fundamentals and applications on in situ spinel formation mechanisms in Al2O3-MgO refractory castables[J].Ceram Int,2012,38(3):2243-2251.
[12]DEEPAK M,DEBASISH S.Effect of in situ spinel seeding on synthesis of MgO-rich MgAl2O4 composite[J].Mater Sci,2007,42(7):7286-7293.
[13]GHASEMI-KAHRIZSANGI S,DEHSHEIKH H G,BOROUJERDNIA M.Effect of micro and nano-Al2O3 addition on the microstructure and properties of MgO-C refractory ceramic composite[J].Mater Chem Phys,2017,189:230-236.
[14]GANESH I,BHATTACHARJEE S,SAHA B P,et al.An efficient MgAl2O3 spinel additive for improved slag erosion and penetration resistance of high-Al2O3 and MgO-C refractories[J].Ceram Int,2002,28(3):245-253.
[15]BAVAND-VANDCHALI M,SARPOOLAKY H,GOLESTANI-FARD F,et al.Atmosphere and carbon effects on microstructure and phase analysis of in situ spinel formation in MgO-C refractories matrix[J].Ceram Int,2009,35(2):861-868.
[16]FAGHIHI-SANI M,YAMAGUCHI A.Oxidation kinetics of MgO-Crefractory bricks[J].Ceram Int,2002,28(8):835-839.
[17]MUSANTE L,MU?OZ V,LABADIE M H,et al.High temperature mechanical behavior of Al2O3-MgO-C refractories for steelmaking use[J].Ceram Int,2011,37(5):1473-1483.
[18]张彦祥,李红霞,杨文刚,等.碳热还原制备镁铝尖晶石晶须及其形成机理[J].材料导报,2018,32(8):1352-1356.ZHANG Yanxiang,LI Hongxia,YANG Wengang,et al.Mater Rev(in Chinese),2018,32(8):1352-1356.
[19]EMMEL M,ANEZIRIS C G,SPONZA F,et al.In situ spinel formation in Al2O3-MgO-C filter materials for steel melt filtration[J].Ceram Int,2014,40(8):13507-13513.
[20]HALMANN M,FREI A,STEINFELD A.Carbothermal reduction of alumina:Thermochemical equilibrium calculations and experimental investigation[J].Energy,2007,32(12):2420-2427.
[21]LEFORT P,TETARD D,TRISTANT P.Formation of aluminium carbide by carbothermal reduction of alumina:Role of the gaseous aluminium phase[J].J Eur Ceram Soc,1993,12(2):123-129.
[22]罗巍,朱伯铨,李享成,等.MgO-C耐火材料中陶瓷相的原位生成机理及其对材料力学性能的影响[J].稀有金属材料与工程,2015,44(S1):438-441.LUO Wei,ZHU Boquan,LI Xiangcheng,et al.Rare Metal Mater Eng(in Chinese),2015,44(S1):438-441.
[23]LIU Yuhong,JING Xinli.Pyrolysis and structure of hyperbranched polyborate modified phenolic resins[J].Carbon,2007,45(10):1965-1971.