共查询到19条相似文献,搜索用时 203 毫秒
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纳米ZrO2/(1-n)SiO2-nAl2O3介孔复合作的制备与光致发光 总被引:1,自引:0,他引:1
采用溶胶-凝胶法和超临界干燥技术制备了(1-n)SiO2-nAl2O3(n=0、0.01、0.1)混合气凝胶体系,并以此作为载体,成功地将纳米ZrO2粒子组装到(1-n)SiO2-nAl2O3介孔体系中,而形成纳米ZrO2/(1-n)SiO2-nAl2O3介孔复合材料。光致发光光谱研究表明,室温下以316nm(3.92eV)波长激发时,纳米ZrO2粒子540nm(2.30eV)荧光峰,在介孔复合体 相似文献
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AlOOH对Al2O3直接凝固注模成型坯体强度等性能影响 总被引:6,自引:0,他引:6
为了改善直接注模成型(DCC)氧化铝的坯体性能,在Al2O3-DCC过程中加入AlOOH本文详细研究了Al2O3+AlOOH体系的湿坯性能,干燥行为及烧结致密化过程,结果表明,少量AlOOH加入可显著提高Al2O3的湿坯抗压强度和弹性模量,当AlOOH体积含量〈3.0%时对干燥过程没有影响,干燥坯体经无压烧结后可获得烧结密度达3.97g/cm^3(99.7%TD)。显微结构均匀的α-Al2O3相。 相似文献
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本文以SiC板粒、ZrOCl2-8H2O、AlCl3和Y(MO)3为原料,利用共沉淀和热压烧结工艺,制备SiC板粒/Y-TZP和(含Al2O3)SiC板粒/Y-TZP复合材料.测试了材料的室温和高温力学性能.研究了添加Al2O3对SiC板粒/Y-TZO复合材料的影响.结果表明,SiC板粒/Y-TZP复合材料与Y-TZP陶瓷相比,其室温强度和韧性出现明显下降,高温强度也没有改善;而在SiC板粒与Y-TZP复合的基础上,添加Al2O3可明显提高材料的强度和断裂韧性,同时,材料的高温强度也获得显著改善. 相似文献
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流态化CVD制备TiO2—Al2O3复合粒子 总被引:6,自引:0,他引:6
本文探讨了流态化CVD反应器中Ti(OC4H9)4水解制备TiO2-Al2O3复合粒子新工艺,借助于SEM、TEM、BET、XRF和EPMA等现代测试手段研究了复合粒子结构和包覆过程特征。结果表明,在流态化CVD反应器中Al2O3超细颗粒以团聚体形式存在,TiO2包覆量随Ti(OC4H9)4进料浓度升高而增加,但反应温度影响不大;在包覆过程中,同时存在成核和成膜,成核包覆使复合粒子比表面积增加,成 相似文献
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Li1+2x+yAlxNdyTi2-x-ySixP3-xO12系统的锂快离子导体研究 总被引:3,自引:0,他引:3
Li1+2x+yAlxNdyTi2-x-ySixP3-xO12锂快离子导体可以用精选的天然高岭石Al4「Si4O10」(OH)8为起始原料,经与Li2Co3、TiO2、NH4H2PO4进行高温(800-1000℃固相反应约20h而制得,一个空间群属于R3C的固溶体导电相可在y=0.5,x≤0.3和y=1.0,x≤0.4的组成范围内发现,该盯具有较好的电导性较低的活化能,起始组成y=1.0,x=0. 相似文献
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Preparation and Properties of Sintering Additives Coated Si3N4 from Heterogeneous Nucleation Processing 总被引:1,自引:0,他引:1
The sintering additives such as Al2O3 and /or Y2O3 were coated on the surfaces of Si3N4 particles via heterogeneous nucleation processing using a buffered pH solution as the precipitation reagent .They nucleated and grew only on the surfaces of Si3N4 and did not form sol particles in solution by TEM observation .The isoelectric point(IEP) of coated Si3N4 was different from that of as-received Si3N4.The IEP of Al(OH)3-coated Si3N4 occurred at pH8.4, which is close to that of alumina .When Al(OH)3-coated Si3N4 particles were coated with Y(OH)3,the IEP of coated Si3N4 powder shifted from pH8.4 to pH9.2 ,similar to that of yttria.In addition ,the rheological data showed that Al2O3 and /or Y2O3 coated Si3N4 suspension is nearly Newtonian and that added Si3N4 suspension shows a shear rate thinning behavior. 相似文献
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Properties of Al2O3-coated nano-SiC have been compared with those of as-received SiC.The isoelectric point(IEP) of SiC changed from pH3.4 to pH7.3 after coating with the alumina precursor,which is close to that of alumina.Because both surfaces of coated SiC and Al2O3 possess higher positive charge at pH=4.5-5.0 ,they are uniformly dispersed in the two-phase aqueous suspensions.Then a mixed powder containing nano-SiC dispersed homogeneously into the Al2O3 matrix was achieved from flocculating the two-phase suspension.Finally,Al2O3/SiC nanocomposited were obtained by coating nano-SiC with Al2O3 ,in which the majority of SiC particles were located within the Al2O3 grains.The observation by transmission electron microscopy(TEM) and the analysis by the X-ray photoelectron spectroscopy(XPS) showed that cracks propagated towards the intragranular SiC rather than along prain boundaries. 相似文献
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采用溶胶-凝胶法,以尺寸约10nm的Fe3O4纳米粒子为种子,碱催化正硅酸已酯(TEOS)水解、缩合,制备了磁性可控的核壳结构SiO2/Fe3O4复合纳米粒子.系统研究了醇水比、NH4OH及TEOS的浓度对复合纳米粒子形貌和性能的影响,并分析了SiO2/Fe3O4复合纳米粒子的生成机理.结果表明,SiO2的生长主要是SiO2初级粒子在Fe3O4表面的聚集生长,醇水比为4∶1、NH4OH浓度为0.3mol/L和TEOS浓度低于0.02mol/L时,随TEOS浓度的增大,SiO2壳层增厚,复合粒子饱和磁化强度下降,矫顽力基本不变,仍具有良好的超顺磁性. 相似文献