M. Emamy
材料科学技术（英文）
Oxide films are incorporated into melts by an entrainment process, and are expected to be present in most
metals, but particularly cast Al alloys. The oxides are necessarily present as folded-over double films (bifilms)
that are effectively cracks. Their effect on the electrochemical behaviour of cast Al-5Zn-0.02In sacrificial
anodes was studied in 3 wt pct sodium chloride solution using the NACE e±ciency evaluation. Three methods
were employed to entrain progressive amounts of oxide in the alloy, including the addition of Al-Zn-In maching
chips to the charge, increasing the pouring height, and agitating the melt. The introduction of oxide bifilms
in the cast alloy resulted in the deterioration of the electrochemical properties of the sacrificial anodes, such
as current capacity and anode e±ciency, and introduced increasing variability in these properties. The results
suggest that corrosion behaviour is strongly related to the presence of bifilms suspended in the liquid alloy
because bifilms provide crack paths allowing the corrodant to penetrate deeply into the metal matrix, and
simultaneously provide localized galvanic cells because of the precipitation of Fe rich intermetallic compounds
on their outer surfaces.
关键词:
Aluminium
,
Sacrificial anode
,
Efficiency
,
Entrainment
,
Bifilm
王云
,
尚鸿燕
,
徐海迪
,
龚茂初
,
陈耀强
催化学报
doi:10.1016/S1872-2067(14)60062-0|
以掺杂不同含量ZnO的Zr0.5Al0.5O1.75为载体，制备了系列1.5% Pd催化剂.在模拟稀燃天然气汽车尾气条件下，测试了催化剂的活性和抗水性，并用N2吸附-脱附、X射线衍射、H2程序升温还原和X射线光电子能谱等手段对催化剂进行了系统表征.研究结果表明， ZnO的添加及添加量对催化剂的活性和抗H2O性有明显影响，其中以ZnO添加量为15%时制备的复合氧化物为载体的催化剂活性最佳.当模拟尾气中不含H2O时，该催化剂对甲烷的起燃温度(T50)和完全转化温度(T90)分别为278和314°C；在含H2O时，该催化剂的T50和T90分别为342和371°C.
关键词:
锆
,
铝
,
锌
,
钯
,
复合氧化物
,
稀燃
,
天然气汽车
,
水抑制
李颢
,
雷骞
,
张小明
,
索继栓
催化学报
doi:10.1016/S1872-2067(12)60589-0
以四丙基溴化铵为模板剂,硅溶胶为硅源,正丁胺为碱源,采用水热合成的方法,将三价离子(Al3+,B3+或Fe3+)和Ti4+同时引入到MFI型分子筛的骨架,得到同时具有氧化和酸催化活性的双功能钛硅分子筛M-TS-1 (M=Al,B或Fe).通过X射线粉末衍射、傅里叶变换红外光谱、紫外-可见漫反射光谱、氨程序升温脱附、电感耦合等离子体原子发射光谱和N2吸附-脱附等温线手段对样品进行了表征.结果表明,三价离子的引入,提高了TS-1的酸强度和酸量.采用乙烯选择氧化为探针反应考察了M-TS-1的催化性能.结果表明,Al-TS-1和B-TS-1在乙烯环氧化及后续的开环溶剂解反应中表现出较高的催化性能,H2O2的转化率在95％以上,H,O,的利用率大于90％,乙二醇和乙二醇单甲醚的总收率可达10％以上.
关键词:
钛硅分子筛
,
铝
,
硼
,
铁
,
双功能催化剂
,
乙烯
,
选择氧化
Liqing CHEN
,
Naoyuki Kanetake
材料科学技术（英文）
Ingot metallurgy (IM) aluminum has long been the subject and attracted the attention of many metallurgists and textural researchers of materials. Due to the introduction of large amounts of ex situ interfaces, however, the textures in powder metallurgy (PM) processed aluminum has been rarely reported. In this article, a pure aluminum plate was prepared $via$ PM route. The starting billet was first produced with uni-axially cold compaction and flat hot-extrusion and then followed by cold rolling processes. The hot-extruded and cold rolling deformation textures of the pure PM aluminum at 50%, 80% and 90% cold rolling reductions were studied by orientation distribution functions (ODFs) analysis. The finite element polycrystal model (FEPM) was finally utilized to simulate the cold rolling textural evolution at various stages of cold rolling. In FEPM simulation, the initial hot-extruded textures were taken into account as inputs. The results showed that typical β-fiber texture formed in pure PM aluminum with the cold rolling reduction increased till 80%, and there was not much change after excessive cold rolling deformation. Homogeneous slip is not the only deformation mode in PM processed pure aluminum plate at over 80% cold rolling reduction. The experimental results were qualitatively in good agreement with the simulated ones.
关键词:
Texture
,
null
,
null
,
null
,
null
