CAJ | 학술논문

背景:包覆层的存在能够阻止纳米粒子氧化、晶体长大、腐蚀和团聚,并赋予特殊的性能.目的:制备SiO2/Ni核壳结构纳米粒子,并评估复合粉体的磁性能.设计、时间及地点:观察性实验,于2005-11/2006-03在大连理工大学纳米复合材料研究实验室完成.材料:应用直流电弧等离子体法制备纳米镍粉,硅酸钠由天津市石英钟厂霸州市化工分厂生产.方法:以硅酸钠为主要原料,通过液相沉淀法在纳米镍粉表面包覆了一层SiO2.主要观察指标:应用X射线衍射仪、傅里叶红外光谱仪、透射电镜、振动样品磁强计、热重分析仪等对复合粉体的结构、形貌和磁性能进行检测.结果:SiO2以非晶态的形式包覆在纳米镍粒子表面,形成了核壳结构,降低了纳米粉体的团聚现象.经SiO2包覆后纳米镍粉氧化温度由287℃提高到385℃.磁性分析结果表明,粉体包覆前由于表面氧化层(NiO)的存在,粉体的磁滞回线偏移;包覆后的粉体由于SiO2的存在,饱和磁化强度降低,矫顽力升高.结论:成功制备了SiO2/Ni核壳结构纳米粒子,SiO2的包覆提高了纳米粉体的抗氧化性,且纳米镍粉具有很好的铁磁性能,矫顽力升高.
배경:포복층적존재능구조지납미입자양화、정체장대、부식화단취,병부여특수적성능.목적:제비SiO2/Ni핵각결구납미입자,병평고복합분체적자성능.설계、시간급지점:관찰성실험,우2005-11/2006-03재대련리공대학납미복합재료연구실험실완성.재료:응용직류전호등리자체법제비납미얼분,규산납유천진시석영종엄패주시화공분엄생산.방법:이규산납위주요원료,통과액상침정법재납미얼분표면포복료일층SiO2.주요관찰지표:응용X사선연사의、부리협홍외광보의、투사전경、진동양품자강계、열중분석의등대복합분체적결구、형모화자성능진행검측.결과:SiO2이비정태적형식포복재납미얼입자표면,형성료핵각결구,강저료납미분체적단취현상.경SiO2포복후납미얼분양화온도유287℃제고도385℃.자성분석결과표명,분체포복전유우표면양화층(NiO)적존재,분체적자체회선편이;포복후적분체유우SiO2적존재,포화자화강도강저,교완력승고.결론:성공제비료SiO2/Ni핵각결구납미입자,SiO2적포복제고료납미분체적항양화성,차납미얼분구유흔호적철자성능,교완력승고.
BACKGROUND: Inhibitory coating can prevent nanoparticle oxidation, grain growth, corrosion and agglomeration, and endow nanoparticle with special properties. ABJECTIVE: To prepare SiO2/Ni core-shell type nanoparticles and assess their magnetic properties. DESIGN, TIME AND SETTING: The observation experiment was performed between November 2005 and March 2006 at Nanometer Compound Material Research Laboratory of Dalian University of Technology, Dalian, Liaoning Province, China. MATERIALS: Nanometer nickel powder prepared by DC arc plasma jet method, Na2SiO3 produced by Bazhou Chemical Industry Branch Factory of Tianjin Quartz Clock Factory (China).METHODS: SiO2/Ni core-shell type nanoparticles were synthesized by coating a layer of SiO2 on the surface of manometer nickel powder via liquid deposition method using Na2SiO3 as the main source material. MAIN OUTCOME MEASURES: Their microstructures and material properties were investigated by X-ray diffraction, Fourier transform infrared spectrometer, transmission electron microscopy, thermo-gravimetric analysis, differential scanning calorimetry and vibrating sample magnetometer. RESULTS: The experimental results showed that SiO2 shell was in an amorphous state around Ni cores and it avoided agglomeration of the Ni nanoparticles. The oxidation temperature of nanometer nickel powder coated by SiO2 elevated from 287 ℃ to 385 ℃. The analysis result of magnetic properties indicated that the hysteresis loop of Ni had an excursion for the existence of anti-ferromagnetic NiO, the silica coating reduced the saturation magnetization and improved the coercivity. CONCLUSION: Preparation of SiO2/Ni core-shell type nanopartieles was successful; silica coating improved the oxidation resistance of nanometer nickel powder, endowed nanometer nickel powder better ferromagnetism and improved the coercivity.