CeO2/ZrO2硅溶胶复合磨料的制备及其对蓝宝石抛光性能的影响

以硅溶胶为原料,通过化学沉淀法对硅溶胶进行铈锆改性,制备出抛光用单分散的CeO2/ZrO2硅溶胶复合磨料.考察了不同铈锆掺杂量的CeO2/ZrO2硅溶胶复合磨料对蓝宝石晶片抛光性能的影响,研究了CeO2/ZrO2硅溶胶复合磨料对蓝宝石晶片的抛光机理.通过透射电子显微镜(TEM)、扫描电子显微镜(SEM)-能谱仪(EDS)、X射线光电子能谱仪(XPS)、X射线衍射仪(XRD)对样品的组成、形貌等进行表征.以所制备的复合磨料对蓝宝石晶片进行抛光,利用原子力显微镜(AFM)检测抛光后的蓝宝石晶片表面粗糙度.结果表明:CeO2/ZrO2硅溶胶复合磨料中最佳的铈锆掺杂量为:铈掺杂量为1.5wt％,锆掺杂量为1.0wt％,材料去除速率可以达到36.1 nm/min,表面粗糙度可以达到0.512 nm,而相同条件下纯硅溶胶抛光后的蓝宝石表面粗糙度为1.59 nm,材料去除速率为18.4 nm/min,该复合磨料表现出较好的抛光性能.     

氧化铈纳米中空球的制备及表征

以聚苯乙烯(polystyrene,PS)微球为模板制备PS/CeO2复合颗粒,然后煅烧去除PS模板形成CeO2纳米中空球。用X射线衍射、透射电镜、场发射扫描电镜、选区电子衍射、能谱分析、Fourier转换红外光谱、热重分析表征样品的相组成、形貌和微观结构。将所制备的CeO2纳米中空球用于甲基橙模拟染料废水的脱色处理。结果表明:CeO2中空球粒径在200～250nm,壳层是由粒径为5～10nm的纳米CeO2颗粒紧密堆积组成,其厚度为15～20nm。经CeO2纳米中空球脱色处理90min后,甲基橙溶液的脱色率可达99%以上,对甲基橙模拟染料废水表现出良好的脱色能力。     

CeO2/SiO2复合磨粒合成与表征

以SiO2溶胶作内核,分别以(NH4)2Ce(NO3)6、CO(NH2)2混合溶液与Ce(NO3)3·6H2O、HMT混合溶液作壳层前驱体,均相沉淀工艺制备了两种不同的CeO2/SiO2复合磨粒.利用XRD、TEM和FF-IR对比了两种磨粒的物相组成、纳米形貌和化学结构,并对包覆机理进行了解释;结果表明:以(NH4)2Ce(NO3)6、CO(NH2)2为原料制备的CeO2/SiO2复合磨粒包覆程度低;以Ce(NO3)3·6H2O、HMT为原料制备的CeO2/SiO2复合磨粒为壳-核包覆结构完整的纳米微球,粒径约110 nm,核层为无定形SiO2,壳层为立方萤石型CeO2颗粒,CeO2壳层与SiO2内核之间存在Si-O-Ce化学键,形成了稳定的壳核结构.     

采用二步法合成核-壳型二氧化硅/二氧化铈复合微粒

以正硅酸已酯为硅源,以氨水为催化剂,无水乙醇为溶剂,采用溶胶-凝胶法并经500℃煅烧1 h后制备了SiO2微粒,运用激光粒度分析方法研究了各原料配比对SiO2粒子大小和粒径分布的影响;再以硝酸铈为铈源,碳酸铵为沉淀剂,十二烷基苯磺酸钠为分散剂,加入SiO2微粒,用化学沉淀法,通过控制反应和焙烧条件,经300℃煅烧1 h后成功合成了核-壳型单分散球状SiO2/CeO2复合微粒.并用差示扫描量热仪/热重分析仪、X射线衍射仪、红外光谱仪、扫描电子显微镜、透射电子显微镜和X射线能谱仪等手段以及zeta电位测定对SiO2/CeO2复合微粒的结构、组成和性能进行了表征.结果表明:SiO2/CeO2复合微粒呈规则球状,粒子分布非常均匀,粒径约300～350 nm;CeO2基本上为膜包覆,伴有少量的CeO2沉积,CeO2包覆层厚度约为30nm;SiO2包覆CeO2后所得复合微粒的表面电性质发生变化,其等电点对应的pH值从2.2增大至5.5.     

Fe_3O_4/SiO_2核壳复合磁性微球的制备和表征

以溶剂热法制备的高磁饱和强度Fe3O4纳米颗粒为核,正硅酸乙酯(TEOS)为前驱体,采用Stber方法,在乙醇/水溶液中,通过氨水催化水解硅醇盐,制得核壳结构的Fe3O4/SiO2复合磁性微球。对制备的样品的物相结构、形貌和磁性能进行了测试表征。结果表明:制备的Fe3O4/SiO2磁性微球呈球形,粒径分布均一,SiO2壳层圆整光滑,厚度为40~70nm。X射线衍射分析显示,Fe3O4/SiO2磁性微球具有尖锐的Fe3O4特征衍射峰,表明包覆过程没有破坏Fe3O4的晶体结构,其室温下的磁滞回线呈顺磁性,且比饱和磁化强度为30A·m2/kg。此外,对SiO2壳层的包覆机理进行了探究。     

以碳球为模板合成氧化铈纳米空心球

以直径约为300nm的碳球为模板,通过无机物前驱体颗粒的自组装制备出CeO2/碳球复合物,煅烧去除碳球模板后,得到CeO2纳米空心球.借助透射电子显微镜、选区电子衍射、场发射扫描电子显微镜、X射线衍射、X射线光电子能谱和热重分析仪等测试手段对复合物的形貌和结构进行了表征.结果表明:产物空心球由面心立方相CeO2颗粒构成...     

Au-SiO2复合纳米微球的制备与表征

采用溶胶-凝胶法制备SiO2纳米微球,以KH-550为粘结剂,利用简单的化学还原法,成功制备出Au-SiO2复合纳米微球,并通过扫描电子显微镜,透射电子显微镜,X射线衍射仪,紫外-可见分光光度计和多功能成像光电子能谱仪对其进行表征.结果表明,Au-SiO2复合纳米微球粒径约130 ～ 160 nm,且颗粒较均匀、分散性较好.样品中金纳米粒子均匀分散于SiO2纳米微球表面,粒径约4～9 nm,具有良好的面心立方结构,晶型良好,且Au物种主要以零价金属态存在.     

超临界法制备多孔纳米Fe_3O_4/SiO_2复合磁性微球及性能

为了制备具有纳米多孔结构的磁性复合微球,采用正硅酸四乙酯(TEOS)和金属氯盐分别作为SiO2和铁氧体的前驱体,通过溶胶凝胶法制备将Fe3O4纳米颗粒分散于SiO2基体中的Fe3O4/SiO2磁性纳米复合微球,并用超临界干燥法对其进行干燥。利用X线衍射(XRD)、红外光谱(IR)、透射电镜(TEM)和振动试样磁场计(VSM)等分析测试手段对合成的材料进行性能表征。结果表明:复合粒子包覆完好、性能优良、分散性良好,制备颗粒的粒径为30 nm,比饱和磁化强度为84.09 A.m2/kg。     

两步反相微乳液法原位制备纳米SiO2/聚甲基丙烯酸甲酯复合微粒

采用两步反相微乳液法原位聚合制备纳米SiO2／聚甲基丙烯酸甲酯(polymethylmethacrylate,PMMA)复合微粒。首先,通过混合2个分别增溶有2种反应物的微乳液,制备纳米SiO2粒子;然后,向混合后的微乳液中滴加单体及引发剂,通过单体的原位聚合反应得到SiO2,PMMA复合微粒。通过相图研究：确定了微乳液法制备复合微粒时初始组分的用量。通过透射电子显微镜、红外光谱、热重分析、X射线光电子能谱等手段对复合微粒进行了表征。结果表明：聚合后的PMMA包覆在SiO2表面．复合微粒的平均粒径为30nm．分散性良好。复合微粒中不能被抽提出来的聚合物占10．08％,这部分聚合物以Si-O-C键形式接枝在SiO2表面。     

超声波引发苯乙烯分散聚合反应制备SiO_2/PS复合粒子

在系统研究超声波场下辅助引发苯乙烯(St)分散聚合反应规律的基础上,利用超声波的分散、粉碎、活化、引发等多重作用,在实现纳米SiO2粒子于反应介质中均匀分散的同时,引发St单体在纳米SiO2粒子表面进行分散聚合反应,制备出二氧化硅/聚苯乙烯(SiO2/PS)复合粒子,并运用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、红外光谱(FTIR)、热重分析(TGA)、X射线衍射谱(XRD)及X射线光电子能谱(XPS)等多种测试手段对SiO2/PS复合粒子的形貌、粒径及分布、表面特性、化学组成及结构等进行了表征。     

Effect of mixed-shaped silica sol abrasives on surface roughness and material removal rate of zirconia ceramic cover

Zirconia ceramic, as mobile phone body-materials, will become increasingly important with the coming of 5G communication technology. Surface quality and material removal rate of zirconia ceramic cover are vital factors to determine its wide application. Therefore, mixed-shaped silica sol abrasives were prepared by ion connecting-inducting method and applied to achieve a good surface quality and a high material removal rate on zirconia ceramic cover by using chemical mechanical polishing (CMP). Mixed-shaped silica sol abrasives contained spherical and beaded shapes were measured by scanning electron microscopy (SEM). Si–O–Al bonds were formed in the mixed-shaped silica sol abrasives and were proved by X-ray photoelectron spectroscopy (XPS). Results of CMP tests showed that zirconia ceramic cover obtained a low surface roughness of 1.824 nm and an efficient material removal rate of 0.33 μm/h. Compared with traditional spherical silica sol abrasives, the polishing rate of mixed-shaped silica sol abrasives increased by 242%. Additionally, solid-phase chemical reactions happened to formed ZrSiO₄, ZrAl₂Si₂O₉ in the CMP process. Moreover, friction coefficient was tested and polishing mechanism had been explored by a contact-friction model in this work.     

纳米氧化锌表面包覆氧化铝复合粉体制备及其光催化活性

在制备ZnO的前驱物 ? 碱式碳酸锌的过程中原位包覆Al2O3，与在ZnO粉体表面包覆的传统工艺相比减少了多次引起粒子团聚的工艺过程，改善了包覆效果. TEM观察表明，包覆的ZnO复合粉体粒径为50 nm左右、包覆层厚为3~5 nm. XPS分析表明，包覆层为Al2O3和ZnO. 光催化活性的测试表明，包覆后的纳米ZnO光催化活性得到了明显降低. 包覆后的纳米ZnO紫外线吸收性能与未包覆的纳米ZnO基本相同，保证了其优异的紫外吸收性能.     

Surface planarization of zirconia ceramic achieved by polyacrylamide grafted nanodiamond composite abrasives through chemical mechanical polishing

Zirconia ceramics are the promising materials for cell phone backplanes in the 5G era, and smoother surfaces and higher removal efficiency are sought after for their precision machining. Although nanodiamond abrasives have high polishing rates, it is easy to bring mechanical scratches and pits on the ceramic surface because of their high hardness, resulting in degradation of the surface quality of the finished workpiece. Therefore, polyacrylamide grafted nanodiamond particles were prepared by solution polymerization method for polishing ceramic wafers. As confirmed by Fourier transform infrared spectroscopy (FTIR), the polyacrylamide has been grafted on the nanodiamond surface. According to the scanning electron microscopy (SEM) and particle size distribution, the composite abrasives have better dispersion than pure nanodiamond abrasives. The results of chemical mechanical polishing (CMP) experiments showed that the composite abrasives could reduce the average surface roughness (Sa, arithmetic mean height) of zirconia ceramic from 28.31 nm to 2.68 nm (scanning area is 500 μm × 500 μm), and the polishing rate remained high compared to pure nanodiamond abrasives, showing superior CMP performance. X-ray photoelectron spectroscopy (XPS) demonstrated that solid-phase chemical reactions occurred during the polishing process to form ZrSiO₄. Meanwhile, contact-wear model combined with contact angle testing indicates that the introduction of polyacrylamide increases the contact area of the nanodiamond on the zirconia wafer surface, thereby significantly enhanced the mechanical effect.     

高填充酸酐固化环氧/二氧化硅复合材料的研究

以环氧树脂、甲基四氢苯酐、叔胺、二氧化硅为主要原料,制得了无机物填充质量分数达50%的二氧化硅-环氧树脂复合材料。对酸酐固化的环氧树脂和由该树脂作为基体的环氧树脂/二氧化硅复合材料的耐热性能、耐化学腐蚀性能进行了研究,并采用扫描电子显微镜对复合材料的断面进行了观察。     

掺氟二氧化锡/二氧化钛复合薄膜的光催化和低辐射性能

采用溶胶-凝胶法在Sn02：F（FTO）低辐射镀膜玻璃衬底上旋涂制备Ti02,获得FTO／TiOz复合薄膜。采用扫描电镜、X射线衍射、紫外-可见透射光谱、Fourier变换红外反射光谱等手段分析了复合薄膜的结构和形貌。结果表明：FTO／TiO2复合薄膜的光催化性随着Ti02薄膜厚度的变化而变化,当Ti02薄膜的厚度为190nm时具有最佳的光催化活性,并从能带角度解释了光催化性能提高的原因;Ti02薄膜能防止FTO在热处理时发生氧化,热处理后的复合薄膜仍具有较好的低辐射性能。     

微–介孔结构Y/MCM-48复合分子筛的合成与稳定性

以正硅酸乙酯为硅源、十六烷基三甲基溴化铵为模板,在氟化物存在的条件下,通过水热法在不同晶化温度和时间下进行复合分子筛Y/MCM-48的合成。利用X射线粉末衍射、Fourier变换红外光谱、N2吸附–脱附、扫描电子显微镜和透射电子显微镜对合成的样品进行表征,同时考察了样品的稳定性及不同晶化时间和温度下样品的晶相。结果表明：在120℃水热晶化36h合成的Y/MCM-48具有良好有序的MCM-48介孔相以及NaY微孔相的双重孔结构,其比表面积高达864 m2/g,平均孔径为2.4 nm。样品经800℃焙烧4 h、100℃水热处理48 h后,复合分子筛的双重孔结构仍然存在。     

纤维素/壳聚糖复合膜的制备及结构表征

通过氯化1-(2-羟乙基)-3-甲基咪唑离子液体([HeMIM]Cl)溶解微晶纤维素,并与壳聚糖的醋酸溶液混合的方法制备了质量比为2∶1的再生微晶纤维素/壳聚糖复合膜。利用红外光谱、X射线衍射、热重分析、扫描电镜和数码相机照片对复合材料的结构进行表征。IR结果表明再生微晶纤维素与壳聚糖分子之间存在着强烈的氢键作用,且二者相容性较好;XRD、TGA结果表明复合材料中纤维素和壳聚糖有较强的相互作用;SEM结果表明复合材料表面粗糙,比表面积较大,可以作为潜在的生物医用材料。     

Nano-scale surface of ZrO2 ceramics achieved efficiently by peanut-shaped and heart-shaped SiO2 abrasives through chemical mechanical polishing

Zirconia ceramics are regarded as the best development target for 5G mobile phone rear covers. However, it is necessary and urgent to improve the surface quality and processing efficiency of zirconia ceramics. Non-spherical silica abrasives were prepared by the KH550 induction method and were used in chemical mechanical polishing (CMP) of zirconia ceramics for the first time. While achieving low surface roughness of 1.9 nm, it has an efficient polishing rate of 0.31 μm/h which is superior to conventional abrasives. Silica particles are peanut-shaped and heart-shaped in the scanning electron microscopy image, and its distinctive morphology provides the possibility of its excellent polishing performance. X-ray photoelectron spectroscopy analysis shows that during the CMP process, silica abrasives and zirconia ceramic undergo a solid phase chemical reaction to form ZrSiO₄. At the same time, the contact wear model established in combination with the coefficient of friction indicates that the two-dimensional surface contact mode of non-spherical silica abrasives on the surface of zirconia ceramics greatly improves its mechanical effect.     

包覆SiO2的硬脂酸相变储能材料的低热固相化学合成及其热性能

采用低热固相化学反应法,一步制备了表面包覆SiO2的硬脂酸相变储能纳米粒子.由红外光谱、X射线衍射和差示扫描量热法对表面包覆SiO2的硬脂酸纳米粒子进行了表征.利用动态光散射激光力度仪测定了材料的粒径分布,同时对材料表面包覆前后的接触角进行了测定.结果表明:硬脂酸纳米粒子表面成功包覆了SiO2层.包覆的硬脂酸纳米粒子为球状,粒径大约为110 nm.包覆的硬脂酸纳米粒子相转变温度为61.4℃,相变过程中的焓值为153.1 J/g,具有良好的蓄热能力,可用于太阳能利用等方面的储能蓄热.     

CuO(CoO,MnO)/SiO_2纳米复合气凝胶催化剂载体的制备及其在合成碳酸二苯酯中的应用

以正硅酸乙酯为硅源,以乙酸铜、乙酸钴和乙酸锰的水溶液为前驱体,采用溶胶–凝胶法和CO2超临界干燥工艺制备了CuO(CoO,MnO)/SiO2纳米复合气凝胶。采用场发射扫描电镜、透射电镜和电子散射能谱分析等对纳米复合气凝胶的微观结构和组成进行了表征。采用Brunauer–Emmett–Teller法测定了纳米复合气凝胶的比表面积、孔径及孔径分布。以纳米复合气凝胶为载体制备了负载型催化剂,用于催化合成碳酸二苯酯(diphenyl carbonate,DPC),并用气相色谱仪对反应液进行了分析。结果表明:纳米复合气凝胶的粒径为20～100nm,孔径为2～8nm,平均孔径为3.16nm,比表面积为664.4m2/g;过渡金属的摩尔含量为13.77%;催化合成DPC的质量收率达27.14%。