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以氨水和硝酸钇为原料制备氧化钇前驱体,考察表面活性剂及其用量对晶粒形貌和尺寸的影响;并在水热条件下研究体系pH、温度及时间对沉淀重整效果的影响.用XRD,SEM技术检测样品的晶型、尺寸和形貌.结果显示,阴离子型表面活性剂的浓度对一级晶粒的尺寸有较明显的影响,而阳离子型表面活性剂和非离子型表面活性剂的浓度对一级晶粒的尺寸的影响不明显.水热条件下对沉淀进行重整,可制备氢氧化钇纳米棒,溶液的碱浓度、温度及时间影响纳米棒的直径和长度.样品经600 ℃焙烧2 h,可制得立方晶相氧化钇,一级晶粒7~20 nm;氢氧化钇纳米棒焙烧后形成的氧化钇仍具有棒状结构. 相似文献
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研究了皂化P507对Fe~(3+)和Fe~(2+)的萃取行为,考察了萃取相比、料液pH、Fe~(3+)质量浓度等因素对萃取的影响。结果表明:氨皂化后的P507对Fe~(3+)有很强的萃取能力;在相比Vo∶Va=3∶1、料液pH为0~2、Fe~(3+)质量浓度0.7g/L条件下,Fe~(3+)萃取率接近100%;但在料液pH≥1.5条件下,部分皂化P507进入下层水相形成水包油型乳化物,导致乳化现象发生;部分Fe~(3+)水解后被皂化P507萃取;皂化P507对Fe~(2+)的萃取过程没有出现乳化现象,Fe~(2+)萃取率随料液pH降低及Fe~(2+)质量浓度升高而降低;P507对Fe~(3+)的萃取能力大于对Fe~(2+)的萃取能力。 相似文献
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Surface mechanical attrition treatment (SMAT) was developed to synthesize nanostructure coatings on alloy surface. The SMAT action was applied in the process of Ni and Cu electroplating coatings on NdFeB substrates in this paper. The role of mechanical attrition during barrel plating on the microstructure, mechanical and corrosion resistant properties of the coatings was exam- ined. The scanning electron microscopy (SEM) observation showed that the mechanical attrition could refine grain size, markedly smooth the coating surface and obviously decrease the number of pore in the coatings. The continuous collisions of glass balls onto the NdFeB samples could induce more beneficial nucleation defects on the coating, which was helpful for increasing nucleation sites and the nucleation rate. The mechanical attrition could also restrain the heterogeneous growth of the coating grain tips due to the abra- sive action of stainless steel balls. The Tafel polarization curve experimental results indicated that SMAT process could enhance the corrosion resistance of coatings on NdFeB. The scratching test revealed that the binding force between coating and NdFeB substrate could be improved dramatically with SMAT process. 相似文献
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