Preparation of Nano/Micron Composite Materials by Process Method

Preparation of Nano/ Micron Composite Materialsby Process MethodGAN Ai- feng, WEI Qi, JI,Yuan, HU Chuan- xin, YAO Jun- min(Departmemt of Materials Sciences & Engineering , Beijing University of Technology , 10022 Beijing)[Abstract] This thesis put forward a method that controls the process of synthesizing nanomaterial to realize the compos-ite of nanomaterial and micronmaterial. This thesis realizes the composite of nanonaterial and micronmaterial by adding micron-material during production of nanomatenal through sol - gel method, also intoduces the lechnique and experiment' 8 processpreparation of nanoconposite malerial, and scesully prepared nanocomposite malerials with nano- PbTiO3 covered on thesurfece of mieron- Ni: According to the sample' s SEM- pictures , the core- shell can be observed plate microstncture, and itisuriform, light, full and good.[Key words] process method; nanocomposite materials; sol- gel method0 Introductionfound.The peparation and picaion of nanonaterial have more 1 Preparation Technique of Nanocompos-and more important inluence on all kinds realms of nationale- ite Materialconomy due to the large specific surface area, high surface en-ery, great srfaece ativitry of nopricle, itis esily sglor 1.1 Choice of nanomaterial preparation methoderated or adsorbed by other matter to reduce its specific surfaceThe preparation methods of nanomaterial include mecha-area, decrease its surface energy, debase its surface activity inthe course of preparation, storage and aplication, then de-nism,, deposition, hydrolyze, hydrothernal, latex, sol- gel etc. zsol- gel method can control the microstructure of material in the mcrease or lose its good property, lead to bad employment andinitial stages of preparation of nanomtrial, lead to the uni-。effet. Studying and manufacture show that the key approachformity reached sub- micron, nano and molecule level, therebythat will improve the nanoparticle' s actual eftct of applicationthe property of material may be cipped, so we choose sol-ge.8is to modify the surface of the highly active powder. The surfaceSeveral merits12.3] of this method:( 1 ) can conlain infusible andmodification method of particle is general that one matter is ab-sedimentary component , infusible powder uniformly disperses insorbed or covered the surface of other maller, and (or) comethe solution that will not produce sediment, aftler glling, in-into being certain chemical bond, the disposal are all the com-compatible powder spontaneously fixes in the syslem of Gel;(2)posite process of double and muliple kinds matter. The particleshigh purity , uneasily introducing foreign substance; (3) fineare generally the composite of nano and micron particles. Thepowder; (4) favorable uniformity of chemistry , compound blendtechnology of nano/ micron composition is more and more impor-on the hevel of molecule, so the chemical constitution inside andtantly reacting on the field of nano technology, also one impor-armong the colloidal particles is completely consistent;(5 ) lowertant advanced direction of future. The technology of nano/ mi-technical temperature;(6) the simple of technique and equip-cron composite can not only modify the surface of powder, im-ments; (7) high contraction ratio while desiccating.rove the application effect of nanoparticles, but also, more im-portantly, provide the preparation of the new - style functional1.2 Preparation technical process of nanocom-material with novel approach'.posite powderThis thesis put forward production of nano/ micron compos-Fig. I shows the complete process of preparing nano/ micronite material by process method, namely control in the intial sta-composite materials by sol- gel method. Metal alkoxide , solvent,ges of preparing nanomaterial, accordingly, realizes the efecwater and catalyst constitute hornogeneous phase solution, form-tive composite of nanomaterial and micronmaterial. And on theing homogeneous phase sol ①after hydrolyze and condensationbasis of some brief analysis, a series of experiments have beenpolymerization;the particles in the sol come into being wet gel ②carried out， meanwhile some revelatory results have beenof three . dimensional net structure after ulteriorly aging; gel iscompo中國煤化工liquid, gel is shrunk[ Received Date] 2004 -05 -23as dryCNMHG*ive superfine powder81一Preparation of Nano / Micron Composite Malenials by Process Methodif it was burmt. Blend the wet gel and mi:ron-interspaces of gel' s three- dimensional net structure; heat treat-trealment and deicaion④, flly egitating ( strong ulrasonic ment of powder was used experimental fumace (highest temper-surge), obaining the compleus ⑤of dry gel covered micron ature reaching 1 600 e,) the stuctre of the average prtielesparicle; the produet was properly heated and ground, we can and the products was analyzed at room lemperature using a scangain the core- shell nanocomposite material ⑥electron microscope (SEM)(JEOL ,6500F ,SE1,30.0 kV).3 Results and Discussion自hFig.2 is a microstructure picture of micron Ni that be trea-ted and desiccated, the picture shows: the shape of the dry Nipowder was trribly iregular, the surface was quite coarse andexisted the trace of being eroded which be propitious to nanop-Fig.1 The comuplele process of preparing nana/ micronarticles absorbing on its surface. Fig.3 is 日microstruelure pic-composile materials by sol- gel methodture of the core - shell particle that nano- PbTiO3 is covered on1.3 Characteristics of nanocomposite by Sol- Gelsurface of micron powder afer bumning and ginding. The Fig. 2sol- gel nanocomposite method controlled in the course ofand Fig. 3 indicated:( 1 )The shape of Ni powder changed greal-the pepaion of namalerial and elired the cmpsile of ly, tansfomin fom ieglar shape imto quite reglar shercinnano and mieron maerials, i was named poces mehod. lt ty; the surfee of Ni powder tansfomed from carsenes intohas sveal mist()implid the echiques , smplied the rlative sotnese. (2)PtTiO, lormed a core : sel plaletechniques of depolymerization, dispersion, composite and sothickness of the plate was about 30 ~ 60 nm, the core - shellon:(2) noparile are sably asoted on the urfece of the plale is uitrm ight fll and god. Fig.4 is lhe SEM piture ofmiconparidles , the aciviy of the nopricle is flen咖the poduetion afer P plate , we can oriouly sce the dtis ofservably and the friendship of employment is improved remark-the core- shell plate, the nanoparticles of the core - shell plateably;(3)the conditions of the composite techniques are facile,reduced the demands for the equipments;(4)the added value ofthe mieromaterial is enhanced because of micronmalerial bear-ing the property of nanomalerial;(5) design of functional materi-als provide with a novel approach.2 Experimental ProcedureThe core- shell superfine powder , nano- PbTiO, covered onthe surface of micron- Ni, were synthesized using analyticallyFig.2 SEM picture of micron particle afer tratmentpure glycol ether( C. H。O2), led acetate[ Pb( CH,C00)2●3H20], butyl titanate I[ CH, (CH2),0]4Ti| and Ni powderwhose size ranges from I μum to3 μm. At first, the lead acetatewas dissolved in glyeol ether and stired, then heated in air at-mosphere al 134 C to remove the crystal water completely; bu-tyl litanate, that was a mole ratio of 1:1 with lead acetale ,wasandante dropped into the mixture at 110 C and strred untilhomogeneous transparent solutions form; obtained wet gel afterFig. 3 SEM picture of the nano/micon composite particlehydrolyze and condensation polymerization in the air atmos-phere ;the Ni powder after treatment is added into the gel as themass ratio of 1: 10 with the production of PbTiO; then fullystirred，make Ni powder disperse in the interspaces of wet gel' sthree - dimensional net structureusing stong ultrasonic surge;the complexus was heated for3 h at 550 C after drying at 80C, then cooling with the furnace , we can gain the nanocompo8-ite materials afiter grinding.This experiment adopl ulrasonie dispersion machine( ss中國煤化Iiero composile4000W) that can uniformly disperse the micron powder in theMHCNMHG82Preparation of Nano 1 Micron Composite Materials by Process Methodrange from several lo tes nano and its size is uneven. The nan-cles of PbTiO3 afer completely drying, the nanoparicles of theoparticles on the surface of Ni powder acumulale ech other new formeion is teribly active and easly aborbed by otherthen forming tight core- sheil plate. Ni powder is in the inte-matter then coming into been steady chemical bond. In addi-spaces of wet gel' s three- dimensional net structure, the plenty‘tion, micron- Ni powder provides nanopaticles with support andof moisture conlent and organie substance were evaporalted dur-special physical enironment. Due to the much dfferenre of theing desication, which brough shrinkage and sffening then conductivily between Ni and PhbTiOz ,we can obviously ohserveprnduced slress in the interpaces of gel. According to Fig 2 andthe configuration of the core- shell plate, whereas the details ofFig3 the shape of Ni powder change grealy before and afer the plate are tribly blurry in SEM. But we can obviously seecomposite. The reason of this change was the stres during des-the deails of nano- PbTiO, in the SEM picture after Pt plate.iccation. There exists three kinds of stress: the first one is capil-The excellent property of this kind of nanocomposite mate-lary force , meniscusproduce in the interspaces of gel when totalrials will be described elsewhere.volume of evaporated liquid and gas is larger than the shrink-4 Conclusionge.Because of capillary phenomenon, the colloidal particle aA new method was brought forward in this thesis, whichround interspaces come under inward gravitation, at the samesynthesized nanocomposite materials in the process of the prepa-time, gel will sifen in the course of desiccation, s0 come into ration of nanomaterial. This experiment succesfully preparedbeing stress concentration in the bigger curvature, make the nano/ mieron composite materials adding micron powder in theshape of Ni paricle lransfom into regular sphericity. The sec-course of the preparation of nanomateial. This method providesond was the stress of expansion , the heated gel will produce gas, the design and preparation of functional materials with a newbecause of the expansion coefficient of gas and liquid grealer approach.than solid, so the expansion of gas and liquid greater than solid[ References ]in the interspaces which remarkably increase the tension in theinterspaces，gas and liquid can flow the surface then evaporated [ 1] LiF s, Yang Y. Apication and Technology of Nano/ Micronas the foree reach certain degree. The last one is the stress ofComposite [ M ]. Beijing: National Defense Industry Press,shrinkage, due to removing the waler and gas during desicca2002.tion, it will produce the stress of shinkage, and this forceis [2] WangSM, XuZX, FuJ Pepantion Tehnology of Nanonme-connected with the structure of gel.terial[ M]. Beijig: Chemical Industry Press, 2002.Fig3 shows the core shel plale of nano PrTO, which [3] Zhang LD. Apliein and Pepneton od Urnfne PordarTechnology[ M]. Beijing: China Petrochemical Press , 2001.is quite uniform, completely. Gel transform into the nanopati-中國煤化工MHCNMHG83