Ultra-fine alumina powder, especially as Europium - alumina powder with high strength, high hardness, resistance to wear, corrosion resistance, high temperature and oxidation resistance, insulation, and a large surface area such excellent characteristics, its dense sintered body works in ceramics, electronic components, high temperature materials, optical, magnetic, biological, nuclear materials has broad applications, its raw materials - alumina powders Preparation is of great significance. Alumina can also Flake, fibrous, porous, spherical, whiskers, nanowires, nanotubes and other morphology exist, and in catalysis, fire retardant, noise, sound absorption, insulation, stealth materials, and other aspects of special uses, therefore explore different morphology of alumina powder Preparation equally important. In this paper, we decided to use a great potential for the development of the microwave method to prepare ultrafine alumina powder. Preparation of the many ultra-fine powder of alumina, the microwave method is efficient, fast, the reaction product of uniform composition, Higher quality advantages. Can facilitate the reaction by regulating the power, processing time and solution composition, pH, Precursor mineralization and the types of factors, in order to achieve effective control of the reaction product of shape, Crystal size and growth characteristics of purposes, particularly in the preparation of oxides. To Al2 (SO4) 3 and different amounts of urea as raw material, two-block copolymer P (St) - b-P (HEA) the existence, Microwave prepared by the spherical coral Boehmite (γ - AlOOH), 800 ℃ calcining, Alumina is a powder. XRD identified the crystal product, TEM and SEM study of the P (St) - b-P (HEA) types, Content on the γ - AlOOH Europium - Al2O3 and morphology of. And legal hot water with the alumina powder conducted a series of follow. MicrowaveAluminaTwo-block copolymer P (St) - b-P (HEA)2.6
表面分析
图9 ( a )和( b )显示的模式样本LC4后浸泡在0.1 mol L - 1的NaCl溶液中24小时,并在0.1 mol L - 1的氯化钠0.05 % CeCl3解决方案168 h respectively.If LC4是沉浸在NaCl溶液中不含有CeCl3 ,其表面变成黑色,并覆盖着大小不同的坑后,只有24个小时(图9 ( b )项) ,这表明,严重的局部腐蚀发生。虽然沉浸在NaCl溶液中含有CeCl3 ,即使在168H条,样本没有坑,并在其表面覆盖了一层薄黄coating.Measured的扫描电镜,黄色的薄涂层表面的样本分布不均(图(一) ,白图) 。乘以1000倍(图) ,可以看到许多白色颗粒,只要2 〜 10微米是LC4 surface.After能谱定性分析,白色颗粒组成铈,铝,氧和少量的铜,锌,镁,其中,行政长官的内容多达57.973 % ,并证明是混合氧化铈和Al和少量的支持组件。同样, LC4是浸泡在0.1 mol L型1NaC1 0.05 % Cell3解决方案的不同时期的时间和样品置于电子microscope.EDS被用来扫描并分析其表面的铈含量结果中可以看出表1.SEM分析表明,随着浸泡时间的延长,白色颗粒较大的增长在数量和规模,使行政长官会同行政会议的内容并不在表面薄膜。
这是因为表面的铝合金具有这种缺陷间,杂质,沉积矿床,间化合物和性质氧化氮films.In事实上,其表面不uniform.Thus时铝合金是沉浸在解决稀土盐,原电池是当地网站成立于表面上和电化学反应发生:金属溶解(铝3E型,铝离子)发生在稍微阳极面积和O2的还原反应要么(氧气2水4电子商务40H - )或氢气分离( 2小时+ 2电子商务氢)发生在阴极面积略有本实验中, O2的还原反应,主要是阴极reaction.No此事有何反应时,那将会使氢离子浓度在阴极面积略有增加, pH值上升,创造条件形成氢氧化铈矿床和解散的Al2O3表面的铝alloy.And时, pH值介于9和第12条,溶解度Ce2O3和Ce (噢) 3 )是为了小于氧化铝,因此,当的反应是否定的极性区表面的铝合金达到一定程度,当pH值大于8 ,氧化铈或氢氧化从而存款形式的电影。高碱性条件加快解散氧化铝氧化膜的性质。因此,形成Ce2O3/Ce ( OH ) 3和解散候补氧化铝表面的铝alloy.With浸泡时间的持续, Al2O3膜终于取代氧化铈/氢氧化物膜。
为了conclude.this机制是阴极涂层理论,解释说,与延长涂层的形成时间,粒子在涂料都有增加密度和规模,因此这样做的比例
铈载于表面氧化和厚度的coating.The存在稀土转化膜阻碍了转移和传输O2和电子之间的表面合金和解决方案,从而稀土转化膜有效地控制阴极还原反应。然而,这种反应作为控制程序中的腐蚀过程中,阴极反应therefore.the减少,导致了铝合金的整体降低率腐蚀而LC4财产坑耐蚀性大大提高。
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