CoAl2O4/Al2O3纳米复合陶瓷的结构与表征

功能材料2004年增刊(35)卷CoAl2O4A2O3纳米复合陶瓷的结构与表征张栋杰,王克宇南京师范大学材料科学重点实验室,江苏南京21009摘要:利用溶胶-凝胶方法制备了的CoAl2O4Al2O图谱。纳米复合陶瓷,并用Xray分析(XRD)、红外光谱(IR)和扫描电镜分析(SEM对其结构进行了分析。结果表明随Al2O3含量增多CoAl2O4尖晶石相从CoAl2O4Al2O3凝胶中的析晶温度升高。SEM形貌也说明,随Al2O3含量增多,CoAl2O4Al2O3陶瓷中形成一定的层状结构。关键词:CoAl2O4;铁氧体;结构;纳米复合中图分类号:O482.54文献标识码:A文章编号:1001-9731(2004)增刊2θ1(°)1引言b: Al..铝酸钴CoAl2O4为尖晶石结晶的立方晶体。1978年,有人将其用于彩色电视机蓝色荧光粉ZnS:Ag的包膜处理大大改善了电视图像的质量。经特殊处理的荧光粉CoAl2O4体系还可以改善发光效率、亮度等指标2。特别是并最近几年,人们也开展了Co-A-O颗粒膜的巨磁电阻隧和多层膜隧道结巨磁电阻等磁性能的广泛研究;对于陶瓷方面,人们也开展了201(°)同类尖晶石结构的ZnFe2O4研究。本文研究了CoAl2O4Al2O3纳米复合陶瓷的结bAL.o构,为进一步研究其巨磁电阻打下基础2实验以分析纯Co(NO3)、Al(NO3、柠檬酸、乙醇、聚乙烯醇为起始原料,采用溶胶一凝胶法合成CoA2O4A2O3纳米复合陶瓷,考虑铝组分的变化对纳米结构的影响,设计了三种组分CoAl2O4,其中x=0.45、0.20和0.10,分别用1#、2#和3#表示。样品图1CoAl2O4Al2O3凝胶在不同热处理温度时的的晶相结构由Dmax-b型ⅹ射线衍射仪测定;形貌谱由JSM-5610LV扫描电镜观测。Fig 1 The XRD curve of CoAl,O4/Al,O3 gel at different3实验结果与分析由图可见,1#凝胶在400°C热处理时仍为非晶图1为凝胶在不同热处理温度时的X射线衍射态在600℃以上时有晶相析出并且是单相CoAl2O4作者简介:张栋杰(19∠通讯作者张栋杰副教授,主要从事铁电、铁磁功能材料与器件的研究。收稿日期:2004-05-05男,河南洛阳人,博中国煤化工CNMHG张栋杰等:CoA2O纳米复合陶瓷的结构与表征274尖晶石。2#凝胶在600°热处理时还是非晶态,而1#凝胶在600°时有CoAl2O4尖晶石结晶,说明2#凝胶中较多的Al2O3阻碍了CoAl2O4尖晶石的形成在600~1400%时,CoAl2O4尖晶石是主晶相,但在1400°C有Al2O3结晶。3#凝胶在700°C热处理时还是非晶态,而1#凝胶在400°℃C时和2#凝胶在600°C热处理时的非晶态温度提高了100-300%,说明凝胶中较多的A2O3阻碍了CoAl2O4尖晶石的结晶和晶粒长大;在800°℃C时,有单相CoAl2O4尖晶石析出样在1400°C有Al2O3结晶。图3在1400°烧结的CoAl2O4A2O3陶瓷的SEM形貌Fig 3 SEM of CoAl2O4Al2O3 ceramics sintered at 1400oC4结论COALO4AlO3凝胶中,随着Al2O3含量的增多CoAl2O尖晶石相的析晶温度升高,较多的Al2O3阻碍4000了CoAl2O4尖晶石的结晶及其晶粒长大;在1400°C有wavenumber/cmAl2O3相结晶。1400°C的SEM形貌也表明,随着A2O3含量的增多,CoAl2O4/AlO3陶瓷中具有层状结构。参考文献[1 Miyata Yoshihihiko. The use of coballalum innate pigmenton the ZnS Ag blue phosphor coat [J]. Jpn Kokai TokkyoKoho,l987,78:192] Yoshiyuki N. Coballaluminate effect on the TV's using age[] Jpn Kokai Tokkyo Koho, 1987, 52: 1191#800℃[3]张振刚,黎超,李成贤等,不同衬底温度下制备CoA-O介质颗粒薄膜的巨磁电阻效应[J.兰州大学学报,199935(1):57-61wavenumbericm[4] FujimoriH, MitaniS, Ohnumas. Tunnel-type GMR图2CoAl2O4Al2O3凝胶在不同温度的红外谱Co-Al-O insulated granular system-its oxygen concentrationFig 2 The IR curve of CoAl2O4/Al2O3 gel at differenttemperature5] Ping Sheng, Ables B, Arie Y Hopping conductivity in图2为凝胶和经过一定温度处理的样品红外光granular metals [J]. Phys Rev Lett, 1973, 31: 44谱。在凝胶样品中3412cm为HO以及OH基团的[6] Mitani, Fujimori, Numas. Spin-dependent tunnelingphenomena in insulating granular system S [].J Magn吸收峰;1728cm'和1378cm为柠檬酸的羧酸基magn Mater. 1997. 165: 14COCOOH的吸收峰;对于800~900°C处理的样品[7] Inoue J, Maekawas. Theory of tunneling magnetoresistance820cm、为Al-O基团的吸收峰而670cm和550cm为CoAl2O4的吸收峰。[8]都有为,陈鹏朱建民.纳米结构ZnFe3O-a-FeO3多晶材图3分别为凝胶在1400℃C处理3h的SEM形貌料中的巨隧道磁电阻效应卩.物理学报,2001,50:2275随着Al2O3含量的增多,从2#和3#有层状形貌出现(下转第2748页)中国煤化工CNMHG功能材料204年增刊(35)卷中棒状纳米材料的可控合成4结论参考文献采用水溶液/ Triton X100正己醇/环己烷反相微1倪天增罗冬冬范力仁等纳米氧化铋的制备与应用]中乳液体系,保持 Triton X-100/环己烷/正己醇的体积比南民族大学学报(自然科学版),200423(1):26-29不变,通过改变加入的水溶液体积和硝酸铋的浓度,(2]吴晓春汤国庆不同制备条件对纳米BiO3发光的影响可得到不同水核半径W0和不同硝酸铋浓度下的不同化学学报,199654:14长径比的棒状纳米氧化铋前驱体,实现了在受限空间Micro-emulsion preparation of nanometer-sizedbasic bismuth nitrate stickFAN Li-ren, CAO Qi-gao, NI Tian-zeng, LI Hai-fen(Faculty of Material Science and Chemical Engineering, China University of Geosciences, Wuhan 430074, China)ized basic bismuth nitrate that was confirmed by TEM andsuccessfully using aqua solution/TritonX-100/hexanol/ cyclohexane reversed phase micro-emulsion system. To fairlycopy the stick structure of water-core, it is very important to optimize the experiment conditions especially keepvolume ratio of Triton X-100/hexanol/cyclohexane and control water-core semi-diameter Wo. With changing volumeof water and concentration of bismuth nitrate, several size stick products have been obtained, their length anddiameter were characterized by TEMKey words: nanometer-sized BiONO3 stick micro-emulsion preparation morphologyL上接第2745页)Structure of CoAl2O4/AlO3 nanocomposition ceramicsZHANG Dong-jie, WANG Ke-yu(Laboratory of Materials Science, Nanjing Normal University, Nanjing 210097, China)Abstract: The CoALO4Al2O, nanocomposition Ceramics were fabricated by sol-gel method with treatment indifferent temperature. The structure was analyzed by XRD, IR and SEM together. The result was that crystallizingtemperature of CoAl2O4 spinel from gel rise, while the layered structure was also formed with Al,O, contentKeywords: CoAl2O4: ferrite; structure: nanocomposition中国煤化工CNMHG