P.L.Mao
金属学报(英文版)
The effect of high temperature solution heat treatment on the microstructure and ten-sile property of as-cast 0Cr17Mn14Mo2N duplex stainless steel was investigated.Itwas found that the morphology ofδ-ferrite in the dual phases microstructures changedgradually from dendritic to lamellar and then to spheroidal,and its distribution be-came more uniform under appropriate treatment.When the treat temperature waslower than 1250C,the spheroidial ratio and the homogeneous distribution o fδ-ferriteincrease with increasing temperature,which corresponds to a better tensile property.In addition,when the treat temperature reached 1250~C and above,the microstructureconsists of coarse equiaxial δ-ferrite grains with the needle austenite at its boundaries,which results in a decrease of the tensile properties of the steel.
关键词:
duplex stainless steel
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null
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null
杨敏
,
沈晓莉
,
姬荣琴
,
李海青
,
丁会利
,
闫卫东
高分子材料科学与工程
三(二苯甲酰甲烷)苯氧基钛酸酯[(dbm)3Ti(Oph)]在MAO作用下,催化p-甲基苯乙烯间规聚合.讨论了催化剂浓度、铝钛比和聚合温度对反应的影响;在催化剂浓度为350 μmol/L、铝钛比为500时,聚合活性最大为7.5×105 g/molTi·h.聚合物有两个熔点183 ℃、203 ℃,分别对应晶型Ⅰ和晶型Ⅲ,玻璃化转变温度为108 ℃左右.同时考察了在此催化体系下p-甲基苯乙烯与苯乙烯间规共聚的情况,苯乙烯和p-甲基苯乙烯的竞聚率分别为0.287、1.806.
关键词:
间规聚合反应
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共聚合
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p-甲基苯乙烯
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苯乙烯
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β-二酮钛配合物
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竞聚率
Materials and Corrosion-Werkstoffe Und Korrosion
A rapid and convenient anodization technology with AC power source to obtain the MAO films formed on magnesium alloy AZ91D in phosphate bath (base electrolyte + Na3PO4) with or without aluminate and silicate was studied. The corrosion resistance of the anodic films was studied by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques and the microstructure and composition of films were examined by SEM and XRD. The results show that Na3PO4 can promote the occurrence of sparking during the MAO process, while abundant heat generated by sparking might enhance the formation of the glassy phase of the compound when the electrolyte contains the additives of NaAlO2 and Na2SiO3 simultaneously. The optimized MAO film is ivory-white smooth by naked eye, while presents porous and microcracks in microscopic scale. The anodic film formed in the alkaline solution with optimized parameters possesses superior corrosion resistance by electrochemical test. The XRD pattern shows that the components of the anodized film consist of MgO, MgAlO2, and MgSiO3. No oxide crystal with P element can be found.
关键词:
micro-arc oxidation;electrochemical impedance spectroscopy;koh-aluminate solutions;corrosion protection;ceramic coatings;alloys;anodization;parameters;resistance;behavior
刘健
,
张开坚
,
陆建生
,
左军
,
杨峰
,
孙建阁
上海金属
doi:10.3969/j.issn.1001-7208.2009.01.005
通过测定P510L钢在不同冷速下的连续冷却转变的膨胀曲线,获得了该钢的CCT曲线;研究了P510L钢连续冷却过程中奥氏体的转变过程及转变产物的组织形态和显微组织,通过对CCT曲线的分析为控轧控冷工艺提供理论依据.
关键词:
P510L钢
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CCT曲线
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显微组织
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显微硬度
Materials and Corrosion-Werkstoffe Und Korrosion
Micro-arc oxidation (MAO) has been accomplished on Mg-Li alloy in alkaline polyphosphate electrolytes without and with the addition of 10?g/L?K2TiF6. The surface/cross-section microstructures of the fabricated coatings were analyzed by scanning electron microscope (SEM); the compositions of the fabricated MAO coatings were analyzed by X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDAX); the corrosion behaviors of bare and MAO coated Mg-Li alloys were evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) in 3.5?wt% NaCl solution. Novel hybrid MAO coatings which showed hybrid composition of MgF2/Ti2O5/Ti6O11/MgO, as well as hybrid structure of a dense inner layer, a dense outer layer and an intermediate layer with some sealed/semi-sealed pores, had been fabricated on Mg-Li alloy in alkaline polyphosphate electrolytes with the addition of K2TiF6. Meanwhile, the corrosion resistance of the fabricated MAO coatings was improved obviously as the result of the addition of K2TiF6 in the electrolytes. Moreover, the multiple roles of ${\rm TiF}_{{\rm 6}}boolean AND{{\rm 2}{-} } $ on the MAO process accounted for the fabrication of the corrosion-resistant hybrid MAO coatings.
关键词:
corrosion resistance;Mg-Li alloy;micro-arc oxidation;az91d magnesium alloy;corrosion-resistance;phosphate electrolytes;ceramic coatings;zn alloy;silicate;performance;aluminum;behavior
YANG Xia
,
GUO Shiju
钢铁研究学报(英文版)
Liquidphase enhanced sintering of powder metallurgy (P/M) 316L stainless steel by addition of sintering aids was studied. 2%-8% of prealloyed FeMoB powder with two different particle sizes was added as sintering aids, and the specimens were sintered in vacuum at 1 200-1 350 ℃. The results show that the fine FeMoB powder (5-10 μm) has stronger activated effect. The sintered density increases with the increase in sintering aid content or sintering temperature. Warm compaction has a better effect on the control of dimensional precision of compacts. The prealloyed FeMoB powder deviated from Mo2FeB2 component can also be sintering aid of P/M 316L stainless steel.
关键词:
P/M 316L stainless steel;liquidphase sintering;activated sintering;FeMoB;sintering aid
余万华
,
周李泉
,
韩静涛
,
张中平
,
刘勇
,
佘广夫
钢铁钒钛
doi:10.3969/j.issn.1004-7638.2006.03.011
采用膨胀法测定了攀枝花新钢钒热轧板厂的高强度P510L钒微合金化钢的CCT曲线,采用金相显微镜分析不同冷速下的显微组织.分析发现,冷却速度较慢(低于10℃/s)时,得到的显微组织为比较粗大的铁素体+珠光体组织;中速冷却时,组织为比较细小均匀的铁素体+珠光体组织;快冷时(高于35℃/s)主要为贝氏体和铁素体组织.进一步采用扫描电镜分析P510L显微组织,发现大量钒的析出物,V(CN)析出物的形态为从球形至长方形,其大小为10～30 nm.
关键词:
微合金钢
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热轧
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显微组织
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CCT曲线
方信贤
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巴志新
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甄睿
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王章忠
材料热处理学报
采用质量损失法研究了化学镀Ni-P镀层及对比材料316L在单相流(20％ H2SO4)和两相流(20％ H2SO4+ 20 g/L黄砂)中冲刷腐蚀行为,以及电化学方法研究了介质温度对Ni-P镀层及316L电化学行为的影响.结果表明,介质温度升高(20 ～80℃),Ni-P镀层腐蚀速率、冲刷腐蚀速率和冲刷腐蚀交互作用增大,但与316L和300℃热处理的晶态镍磷镀层相比,介质温度对镀态和200 ℃热处理的非晶镍磷镀层影响较小.镀态镍磷和316L的腐蚀电流密度随介质温度升高而增大,容抗弧半径则随介质温度升高而减小.Ni-P镀层腐蚀和单相流冲刷腐蚀机制是均匀腐蚀,而两相流中则为均匀腐蚀+犁削机制.
关键词:
Ni-P镀层
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316L
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腐蚀
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冲刷腐蚀
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阻抗谱
Applied Surface Science
A novel kind of micro-arc oxidation (MAO) coating was prepared on magnesium alloy surface coated with rare earth conversion film (RE-film) in an alkaline aluminum oxidation electrolyte by AC power source. Inspection of scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) microspectroscopy, the structure and composition of MAO coating formed on AZ91D with RE-film under different applied voltages were investigated and the performance of the optimized MAO coating compared with the MAO coating directly formed on magnesium alloy. As the pretreatment of magnesium alloy with RE-film, the cerium oxides can be incorporated into the MAO coatings, reduce porosity of the MAO coating surface and enhance the thickness of MAO coating. These structure features and the cerium oxides incorporated into the MAO coating result in greatly improved corrosion resistance. Base on electrochemistry impedance spectroscopy (EIS) measurement, the electronic structure and composition analysis of the MAO coating, a double-layer structure, with a compact inner layer and a porous outer layer, of the coating was proposed for understanding its corrosion process. (C) 2010 Elsevier B.V. All rights reserved.
关键词:
Magnesium alloy;Rare earth conversion film;Micro-arc oxidation;Porosity;az31 magnesium alloys;micro-arc oxidation;mg-al alloys;electrolyte;resistance;cerium;phosphate
