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为了实现Cu对纳米SiC的表面包覆改性,分别采用歧化反应和置换反应两种方法制备了Cu/纳米SiC复合粉体.利用扫描电子显微镜、透射电子显微镜和能谱仪研究了Cu/纳米SiC复合粉体的微观形貌、聚集状态、粒径以及Cu和纳米SiC的质量分数.实验结果表明:单个复合粒子的粒径约为100 nm;针对随机选择的两种方法制备的复合粉体的两个不同区域进行的分析表明,歧化反应条件下Cu的质量分数分别为37%和35%,成分均匀;置换反应条件下Cu的质量分数分别为79%和25%,成分差异大.歧化反应法比置换反应法的包覆效果好,实现了Cu对纳米SiC的均匀性包覆. 相似文献
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单分散纳米CeO_2和Cu-Ce-O催化剂的制备、表征及其催化性能 总被引:1,自引:0,他引:1
以硝酸铈、硝酸铜和氢氧化钠为原料,使用超声双雾化工艺实现微区反应制备了纳米CeO2粉体和掺铜CeO2复合粉体,并利用XRD、TEM、HR-TEM、FT-IR和BETN2等手段对其成分、物相结构、形貌及颗粒大小进行表征;并将所制备的粉体作为催化剂考察其对CO的催化氧化性能.结果表明,所制备的纳米CeO2粉体和掺铜CeO2复合粉体粒径均为4~5 nm,球形,粒度分布均匀,且单分散性好;CeO2催化剂粉体粒径越小、比表面积越大,对CO的催化氧化活性越高;Cu-Ce-O催化荆对CO具有最好的催化氧化活性,表明铜的掺入有利于明显提高CeO2催化剂在CO催化氧化反应中的低温活性,降低起燃温度. 相似文献
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采用水热合成法制备纳米TiO2粉体,以自制的1100分散剂对粉体进行原位包覆和后包覆,考察了分散剂用量、pH值对包覆体系分散性的影响,利用XRD和TEM进行结构表征和形貌观测,并采用分光光度法对纳米TiO2粉体水分散体系稳定性进行了检测,在此基础上制备了纳米TiO2/有机复合涂膜.研究表明:原位包覆制备的纳米TiO2中,锐铁矿相的质量分数为100%,分散较均匀,纳米TiO2粉体的平均粒径约为20nm;分散剂用量为8.0%、pH值为3和10时,其水溶液分散稳定性较高;后包覆制备的纳米TiO2粉体由锐钛矿相(73%)和金红石相(27%)构成,纳米TiO2粒子处于团聚状态,无明显颗粒形态;涂膜经自然光照射24h后,对大肠杆菌的杀灭率为99.8%;良好的分散工艺和有效的分散剂可充分发挥纳米TiO2的光催化功能. 相似文献
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《中国粉体技术》2017,(3):50-56
采用机械力化学法,在水介质中采用滑石研磨和滑石与TiO_2共混研磨方式制备滑石-TiO_2复合粉体,探讨影响复合粉体颜料性能的工艺因素,表征复合粉体的颜料性能与显微结构。结果表明:滑石的颗粒粒径随研磨强度的增加呈先减小后增大、再逐渐趋于稳定的规律,可满足与TiO_2复合的基体要求;滑石-TiO_2复合粉体表面滑石颗粒紧密包覆TiO_2颗粒层,具有与钛白粉相似的颜料性能;TiO_2质量分数为70%的滑石-TiO_2复合粉体的遮盖力为10.45 g/m~2,TiO_2质量分数为66%的复合粉体的遮盖力为12.50 g/m~2,2种复合粉体的遮盖力分别达到金红石型TiO_2的105.26%和88%;滑石-TiO_2复合粉体紫外线屏蔽性能与金红石钛白粉相当。 相似文献
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《中国粉体技术》2015,(4)
通过湿法机械研磨白炭黑进行解聚与分散以及白炭黑与Ti O2共混研磨制备白炭黑-Ti O2复合粉体,对制备过程中的各种因素进行优化,对白炭黑-Ti O2复合粉体的结构、粉体颜料性能以及紫外光作用下的光学性能进行表征。结果表明:影响白炭黑与Ti O2研磨复合的因素及优化条件是,白炭黑中位粒径为2.288μm,球料质量比为5∶1,浆体中粉体颗粒的质量分数为18%,研磨时间为60 min,分散剂质量分数为6%;白炭黑-Ti O2复合颗粒以Ti O2在白炭黑团聚体表面包覆为特征;白炭黑-Ti O2复合粉体与钛白粉颜料性能相似,并因白炭黑与Ti O2的协同作用而具有紫外线屏蔽功能。 相似文献
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采用溶胶凝胶法制备纳米TiO2,CeO2粉体,纳米TiO2-CeO2复合材料。并对其单一粉体和复合粉体的紫外吸收性能加以研究。分析了不同的铈钛比例和复合方式对其复合材料的颗粒形状,粒径大小以及紫外屏蔽效果的影响。研究结果表明采用溶胶凝胶法可制备粒径〈100nm的TiO2、CeO2以及TiO2.CeO2复合粉体。TiO2-CeO2复合粉体的紫外屏蔽效果优于纳米TiO2、CeO2的单一粉体.采用TiO2溶胶与CeO2溶胶混合制备的TiO2-CeO2复合粉体的紫外吸收性较好,该复合粉体中铈钛比例为1:3。 相似文献
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Mahesh Kumar Mani Giuseppe Viola Mike J. Reece Jeremy P. Hall Sam L. Evans 《Journal of Materials Science》2014,49(6):2578-2587
Near-equiatomic Fe–Co alloy composites containing 0, 5 and 10 vol% of uncoated and coated SiC particles were prepared by applying a uniaxial pressure of 80 MPa at 900 °C for 5 min in a spark plasma sintering furnace. The SiC particles used in this study were coarse, with an average particle size of 20 μm and their surfaces were coated with four different types of coatings, namely Ni–P, Cu, Co and duplex Cu and Ni–P by an electroless plating method. Quasi D.C. magnetic, bending and hardness tests were performed on the composites. The influence of particulate coatings on the magnetic and mechanical behaviour of the composites was investigated by correlating their properties with their microstructures as observed using scanning electron microscopy and optical microscopy and crystallographic information as obtained using X-ray diffraction. The cobalt coated particles were found to exhibit the best wettability with the matrix without the formation of deleterious intermetallic compounds at the interface. Because of the better interfacial bonding in the composites with Co coated particles, there was an enhancement in flexural strength and permeability compared to the uncoated and other coated particulate composites studied. In addition, inclusion of cobalt coated SiC particulates produced an increase in hardness and a decrease in coercivity compared to the monolithic material. 相似文献
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为了增强微米级SiC陶瓷颗粒与金属基体的结合力,采用化学镀铜法对SiC颗粒表面进行了改性处理,使SiC颗粒在金属基体液中分散更均匀、镀覆更好。通过正交试验法优化了化学镀铜工艺的主要参数,研究了其主要工艺条件对化学镀铜的影响;分别通过JSM7500F,S-3400N扫描电镜(SEM)对微米级SiC颗粒镀铜前后的表观形貌进行了观察分析,利用X射线衍射仪(XRD)对其镀铜前后的组成进行了表征,并测试了镀铜层与SiC颗粒的结合力;同时对比了微米级SiC颗粒镀铜前后对锌基复合材料微观形貌的影响;讨论了镀液中配位剂、pH值、还原剂等对铜镀层的影响。结果表明:随着镀液中配位剂、还原剂含量的增加,单位时间内微米级SiC颗粒表面镀铜层的质量先增加后降低,pH值的升高显著降低了镀铜的诱导时间;可实现微米级SiC颗粒表面化学镀铜层的均匀镀覆,且结合良好。 相似文献
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采用化学共沉淀法制备了葡聚糖包覆的纳米Fe3O4颗粒,平均粒径为6nm,包覆层厚度约为3~5nm,纳米Fe3O4粒径分布较窄.红外光谱分析可知,葡聚糖与纳米Fe3O4主要以氢键结合,结合Zeta电位和热重分析,分散作用主要是空间位阻作用,葡聚糖的包覆量约为10%.吸光度测试表明,随着葡聚糖用量的增加,悬浮液的稳定性提高.用量为25%时,悬浮液在室温下静止1周,无分层现象.包覆样的饱和磁化强度为60emu/g,具有良好的超顺磁性. 相似文献
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SiC/PyC复合涂层碳纤维微观结构及氧化行为研究 总被引:1,自引:0,他引:1
采用两步法在碳纤维表面制备了碳化硅/热解碳(SiC/PyC)复合涂层,PyC内涂层的制备采用等温化学气相渗透法,SiC外涂层的制备采用碳热还原法.借助X射线衍射、场发射扫描电镜、透射电镜分析了SiC/PyC复合涂层碳纤维的物相组成以及微观结构,利用热重分析研究了SiC/PyC复合涂层、PyC涂层以及无涂层碳纤维的氧化行为.结果表明,在碳纤维表面制备的SiC/PyC复合涂层连续致密、厚度均匀,PyC内涂层厚度约为200nm,SiC外涂层厚度约为160nm,SiC层中存在大量孪晶面高度有序的SiC孪晶.SiC/PyC复合涂层能够有效地改善碳纤维的抗氧化性能,较无涂层碳纤维起始氧化温度提高了近250℃. 相似文献
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《Composites Science and Technology》2007,67(11-12):2377-2383
Polymethylsiloxane (PMS) was used as a binder to make self-supporting SiC preforms for pressurized aluminum melt infiltration. The SiC particles were coated with preceramic polymer by spray drying; this ensured a fine and homogeneous distribution coupled with a high yield of the binder. The conditioned SiC powder mixtures were processed into preforms by warm pressing, curing and pyrolysis. A polymer content of 1.25 wt.% conferred sufficient stability to the preforms to enable composite processing. Using this procedure, SiC preforms with various SiC particle size distributions were prepared. The resulting Al/SiC composites with SiC contents of about 60 vol.% obtained by squeeze casting infiltration exhibit a 4-point bending strength of ∼500 MPa and Young’s moduli of ∼200 GPa. These values are comparable to those of compositionally identical, but binder-free composites. It is thus shown that the PMS-derived binder confers the desired strength to the SiC preforms without impairing the mechanical properties of the resulting Al/SiC composites. 相似文献