材料期刊网

pp和p碰撞中J/ψ的光生过程（英文）

朱佳庆 , 何俊伟 , 李云德

原子核物理评论

计算了pp和p碰撞中J/ψ的领头阶光生过程的产额。运用非相对论量子色动力学回顾了重夸克偶素产生的色单态机制与色八重态机制,并将它们分别用于处理直接光子过程和分解光子过程。通过与J/ψ产生的领头阶结果的对比可以看出,光生过程对J/ψ产额的修正在大横动量区域变得明显。

关键词: 光生过程 , 大横动量区域 , 重夸克偶素

基于3D打印的微微型混合工质J-T制冷器实验研究

王昂 , 公茂琼 , 吴剑峰

工程热物理学报

微微型节流制冷器在微小元件和制冷应用中有广阔的前景.本文通过对搭建一微型压缩机驱动的微型混合工质节流制冷器系统,取得初步结果.该微微型J-T节流制冷器采用3D打印技术,通道特征尺寸为0.1 mm,突破了传统机械加工的极限.通道深宽比达到8:1.初步实验表明,微微型J-T节流制冷器达到了230 K温区.由于采用微型压缩机驱动,系统结构紧凑,可在便携生物储存设备、低温医疗以及电子器件冷却等领域应用并能长期运行.

关键词: 微微型节流制冷器 , 混合工质 , 3D打印

X70管线钢J1d和K1a与V型缺口Ak关系研究

朱杰武 , 柳永宁 , 许雁 , 冯耀荣

机械工程材料 doi:10.3969/j.issn.1000-3738.2005.06.007

在不同温度下测试了X70管线钢动态断裂韧度K1d、J1d和止裂韧度K1a以及夏氏V型缺口冲击韧度Ak,对三者的关系进行了分析.结果表明:温度和加载速率都对断裂韧度产生影响;加载速率变化引起的韧-脆断裂转变具有热激活特征,在热激活分析基础上,在应力强度因子速率K=15 MPa·m1/2s-1条件下,得出断裂韧度、止裂韧度和冲击韧度三者的关系:Ak=4.84×106T-2.8K1d(或K1a).可以用小试样Ak数据计算得到K1d和K1a.

关键词: 管线钢 , 断裂韧度 , 止裂韧度 , 韧-脆断裂转变

金属环境中低能D(d, p)T反应的研究

吕会议 , 王铁山 , 陈建勇 , 杨振 , 刘盛进 , 方开洪

原子核物理评论

近年来一系列实验表明,金属环境中的低能带电粒子引起的核反应截面与气体靶中的相比出现明显增大,这种现象通常被归结为电子屏蔽效应. 全面介绍了金属环境中D(d, p)T反应电子屏蔽效应的测量方法、数据分析和实验结果的规律性,并简要论述了包括德拜等离子体模型在内的各种理论模型对实验结果的解释. 通过研究,可以获得有关核物理、核天体物理和凝聚态物理的宝贵知识.

关键词: 低能核反应 , 电子屏蔽效应 , 德拜模型

Electrodeposition of high corrosion resistance Cu/Ni-P coating on AZ91D magnesium alloy

Applied Surface Science

High corrosion resistance Cu/Ni-P coatings were electrodeposited on AZ91D magnesium alloy via suitable pretreatments, such as one-step acid pickling-activation, once zinc immersion and environment-friendly electroplated copper as the protective under-layer, which made Ni-P deposit on AZ91D Mg alloy in acid plating baths successfully. The pH value and current density for Ni-P electrodeposition were optimized to obtain high corrosion resistance. With increasing the phosphorous content of the Ni-P coatings, the deposits were found to gradually transform to amorphous structure and the corrosion resistance increased synchronously. The anticorrosion ability of AZ91D Mg alloy was greatly improved by the amorphous Ni-P deposits, which was investigated by potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS). The corrosion current density (I(corr)) of the coated Mg alloy substrate is about two orders of magnitude less than that of the uncoated. (C) 2011 Elsevier B. V. All rights reserved.

关键词: AZ91D Mg alloy;Electrodeposition;Ni-P;Corrosion resistance;phosphorus incorporation;pure magnesium;thin-films;ni;pretreatment;deposits;behavior;copper

J4不锈钢及化学镀Ni-P和Ni-Cu-P镀层在液-固两相流中的冲刷腐蚀行为

方信贤白允强王章忠

金属学报 doi:10.3724/SP.J.1037.2009.00499

用质量损失法系统研究了不同温度(25和50℃)和不同冲刷速率(0.63-1.88 m/s)下,J4不锈钢、Ni-P和Ni-Cu-P合金镀层, 及对比材料316L不锈钢在液-固两相流(20% H₂SO₄+20 g/L Al₂O₃)中的冲刷腐蚀行为. 结果表明:不锈钢和镀层的抗冲刷腐蚀性能由高到低依次为镀态Ni-Cu-P, 镀态Ni-P,热处理态Ni-Cu-P, 316L, J4. 提高两相流介质温度均使它们的冲刷腐蚀速率增大. 316L不锈钢在25℃液-固两相流介质中的冲刷腐蚀速率分别为镀态Ni-Cu-P, 镀态Ni-P和热处理态Ni-Cu-P镀层的8.5倍, 8倍和2.6倍以上, 而在50℃下分别为392倍, 80倍和14.8倍以上; J4不锈钢在25和50℃液-固两相流介质中的冲刷腐蚀速率分别为316L不锈钢的28倍和13倍以上. 在25和50℃, J4不锈钢分别为选择性腐蚀和均匀腐蚀, 而316L不锈钢均为轻微选择性腐蚀, Ni-P和Ni-Cu-P合金镀层均为均匀腐蚀.

关键词: Ni-Cu-P , Ni–P , J4 stainless steel , 316L stainless steel , liquid–solid two–phase flow , erosion and corrosion

J4不锈钢及化学镀Ni-P和Ni-Cu-P镀层在液-固两相流中的冲刷腐蚀行为

方信贤 , 白允强 , 王章忠

金属学报 doi:10.3724/SP.J.1037.2009.00499

用质量损失法系统研究了不同温度(25和50℃)和不同冲刷速率(0.63-1.88 m/s)下,J4不锈钢,Ni-P和Ni-Cu-P合金镀层,及对比材料316L不锈钢在液-固两相流(20%H_2SO_4+20 g/L Al_2O_3)中的冲刷腐蚀行为.结果表明:不锈钢和镀层的抗冲刷腐蚀性能由高到低依次为镀态Ni-Cu-P,镀态Ni-P,热处理态Ni-Cu-P,316L,J4.提高两相流介质温度均使它们的冲刷腐蚀速率增大.316L不锈钢在25℃液-固两相流介质中的冲刷腐蚀速率分别为镀态Ni-Cu-P,镀态Ni-P和热处理态Ni-Cu-P镀层的8.5倍,8倍和2.6倍以上,而在50℃下分别为392倍,80倍和14.8倍以上;J4不锈钢在25和50℃液-固两相流介质中的冲刷腐蚀速率分别为316L不锈钢的28倍和13倍以上.在25和50℃,J4不锈钢分别为选择性腐蚀和均匀腐蚀,而316L不锈钢均为轻微选择性腐蚀,Ni-P和Ni-Cu-P合金镀层均为均匀腐蚀.

关键词: Ni-Cu-P , Ni-P , J4不锈钢 , 316L不锈钢 , 液-固两相流 , 冲刷腐蚀

Study on electroless Ni-P-ZrO2 composite coatings on AZ91D magnesium alloys

Surface Engineering

Electroless Ni-P-ZrO2 composite coatings on AZ91D magnesium alloys was developed and their characteristics were investigated. The experimental results showed that the composite coatings were uniform and compact. The hardness of Ni-P-ZrO2 composite coatings reached the maximum value at 350 degrees C heat treatment, and then decreased at 400 degrees C. The nickel phosphor alloys provided solution strengthening and precipitation strengthening, while the ZrO2 nanoparticles provided dispersion hardening, making the composite coatings harder than that of Ni-P coatings. The wear resistance of Ni-P-ZrO2 composite coatings was obviously superior to Ni-P coatings, especially with longer wear time, which can be attributed to the dispersion strengthening and load support effect of ZrO2 in the coatings. The Ni-P-ZrO2 coatings exhibited better corrosion resistance than that of Ni-P coatings owing to codeposition of ZrO2 together with NiP leading to a more compact composite coating.

关键词: electroless composite coatings;Ni-P-ZrO2;compact;ZrO2 nanoparticles;concentrated slurry;magnesium alloys;AZ91D;microstructure;heat;treatment;hardness;solution strengthening;precipitation;strengthening;dispersion strengthening;wear resistance;load support;corrosion resistance;corrosion;substrate

A Novel near Net-Shape Technique for P/M Parts with Large H/D Ratio

Yong LIU , Baiyun HUANG , Kechao ZHOU , Hongwu OUYANG , Yuehui HE

材料科学技术（英文）

In order to overcome the shortcomings of conventional hot pressing, a novel near net-shape technique, called radial hot pressing, for P/M parts with large height-to-diameter (H/D) ratio was introduced. Effects of processing parameters on the microstructures and density of P/M TiAl base alloy valves were studied. Results show that the radial hot pressing is an effective technique for manufacturing valves with a H/D ratio of about 10:1, and the perfect joint interface between the Mo sheet and the parts is helpful for subsequent HIPing.

关键词: Near net-shape technique , null , null

Electroless Ni-P plating with a phytic acid pretreatment on AZ91D magnesium alloy

Materials Chemistry and Physics

A phytic acid conversion film with especial functional groups was proposed as the pretreatment layer between Ni-P coating and AZ91D magnesium alloy substrate, to replace the traditional pretreatment. In the process, the silane coupling agent was adopted as connector between conversion film and palladium ion with catalysis. The microstructure of the phytic acid conversion coatings was observed using scanning electronic microscopy, while the composition and functional groups were analyzed by energy dispersive spectrometer and Fourier transform infrared spectroscopy. The bonding between Si-OH of the silane coupling agent and hydroxyl of phytic acid was validated by X-ray photoelectron spectroscopy, and the existence of palladium ion was also verified. The subsequent Ni-P deposited on the layer was also characterized by its structure, morphology, and corrosion resistance. The results show that the Ni-P coatings with the phytic acid pretreatment on AZ91D magnesium alloy have good corrosion resistance. (C) 2010 Elsevier B.V. All rights reserved.

关键词: Magnesium alloy;Phytic acid;Electroless nickel plating;Coupling agent;conversion coatings;corrosion;microstructure;nanoparticles;performance;technology;composites;deposition;behavior;layer