烧结NdFeB永磁体表面微弧氧化涂层的制备及性能（英文）

为了提高烧结NdFeB永磁体的耐蚀性,在铝酸盐溶液中采用二步微弧氧化工艺在烧结NdFeB永磁体表面制备了氧化铝陶瓷涂层。微弧氧化过程中,电压-时间曲线可大致分为4个阶段,与阀金属处理的曲线基本一致。烧结NdFeB表面制备的涂层呈现出典型的微弧氧化多孔形貌,厚度大约为5μm。涂层中仅含有Al_2_O3结晶相,并含有少量的Fe、Nd和P元素。微弧氧化处理后,烧结NdFeB的表面粗糙度有所增加,耐蚀性较基体提高了1个数量级。然而,微弧氧化处理后烧结NdFeB磁体的剩磁和最大磁能积较未处理NdFeB有所下降。     

高铌γ-TiAl合金表面微弧氧化陶瓷涂层的耐蚀性及高温氧化行为

利用微弧氧化技术（MAO）在硅酸钠和氢氧化钾溶液中对高铌γ-TiAl合金表面原位生长陶瓷涂层以提高γ-TiAl合金的抗高温氧化性能。采用扫描电子显微镜（SEM）、X射线衍射仪（XRD）、X射线光电子能谱（XPS）、电化学工作站和箱式电阻炉高温氧化测试分析涂层的表面及截面形貌、相组成、元素化学结合状态、耐蚀性和高温氧化行为。XRD和XPS结果表明,陶瓷涂层主要由Al₂TiO₅、SiO₂和Nb₂O₅组成。涂层与基体界面结合良好,厚度约2.15 μm。高铌γ-TiAl合金经微弧氧化处理后,在3.5%NaCl溶液中的腐蚀电流降低近1个数量级。微弧氧化处理试样在800~900 ℃中的氧化增重仅为基体的8.9%~37.5%。微弧氧化陶瓷涂层将基体的氧化激活能从247.79 kJ/mol增加到涂层试样的574.41 kJ/mol。     

纳米Si3N4 对TC4钛合金微弧氧化层微观结构和性能的影响

在基电解液中加入氮化硅纳米颗粒,对TC4钛合金进行微弧氧化（MAO）处理,研究了Si₃N₄浓度对微弧氧化层表面形貌、耐蚀性和耐磨性的影响。添加Si₃N₄的MAO层呈现多孔结构,当Si₃N₄浓度为1 g/L时,涂层厚度最大,且经过7 d的酸腐蚀试验,该涂层的耐蚀性良好,腐蚀速率最低,约为0.057 mg·cm^-2·d^-1。随着Si₃N₄的加入,MAO涂层的抗菌性能先升高后降低。当Si₃N₄的添加量为1 g/L时,该MAO层的抗菌性能最好。Si₃N₄的加入能明显提高涂层在模拟海水中的耐磨性。当Si₃N₄的添加量为3和4 g/L时,所得涂层的摩擦系数低且稳定,且添加3 g/L Si₃N₄制备来的MAO涂层表现出优异的耐磨性。     

PREPARATION OF MICROARC OXIDATION COATING ON (Al2O3-SiO2)sf/AZ91D MAGNESIUM MATRIX COMPOSITE AND ITS ELECTROCHEMICAL IMPEDANCE SPECTROSCOPIC ANALYSIS\par

在硅酸盐电解液体系中, 采用交流微弧氧化方法在增强体体积分数为33%的 (Al₂O₃-SiO₂)_sf/AZ91D镁基复合材料表面制备出完整的保护性氧化膜. 利用SEM, EDS和XRD分析了氧化膜的形貌、成分和相组成, 测量了膜层的显微硬度分布. 采用电化学阻抗谱(EIS)评价了微弧氧化表面处理前后复合材料的电化学腐蚀性能, 确立了不同浸泡时间对应的等效电路. 结果表明, 微弧氧化膜主要由MgO和Mg₂SiO₄相组成, 最大硬度达到1017 HV. 氧化膜电化学阻抗模值|Z|与镁合金基体相比大幅度提高, 耐腐蚀性能明显高于基体. 在3.5%NaCl溶液里浸泡96 h后, EIS出现感抗弧, 显示膜内部开始出现点蚀破坏. 氧化膜耐蚀性由膜内致密层特性所决定.     

TiO2纳米粒子对铝锂合金微弧氧化膜结构及性能的影响

为改善微弧氧化膜层的耐蚀性及力学性能,向电解液中添加TiO₂纳米粒子后对2297铝锂合金进行了微弧氧化。利用SEM、XRD、EDS、辉光放电表征技术及电化学测试技术,分析了TiO₂纳米粒子对微弧氧化膜结构、力学性能及耐蚀性的影响。结果表明：添加TiO₂纳米粒子后,微弧氧化膜层变得平坦致密。随着TiO₂纳米粒子添加量的提高,膜层表面放电通道的孔径逐渐减小,数量逐渐增多。TiO₂纳米粒子会抑制熔融Al₂O₃与电解液中$ {\rm{SiO}}_{\rm{3}}^{{\rm{2 ^- }}}$的接触,所以膜层中Si元素的含量随TiO₂纳米粒子添加量的增加而逐渐下降(原子数分数从初始的10.27%下降到了3.10%)。显微硬度测试结果表明,TiO₂纳米粒子的引入增加了膜层的致密度及平整度,所以膜层的硬度得到了提升(添加1 g/L TiO₂纳米粒子后硬度提高了15%)。电化学测试结果显示,当微弧氧化的其它条件相同时,TiO₂纳米粒子的适量添加会提升膜层的耐蚀性,但过量添加时,由于膜层放电通道数量的增多等原因,其耐蚀性下降。     

石墨对TA7钛合金表面微弧氧化涂层组织及耐蚀性的影响

为提高TA7钛合金的耐腐蚀和耐磨损性能,在钛合金表面制备了微弧氧化涂层,研究了石墨颗粒对微弧氧化涂层组织结构及耐蚀性的影响。结果表明,在基础电解液中加入石墨颗粒能够显著提高TA7钛合金微弧氧化涂层的厚度,降低微弧氧化涂层的表面粗糙度和显微硬度,且随着石墨含量的升高,微弧氧化涂层的厚度增大,但显微硬度减小,表面粗糙度基本保持不变;微弧氧化涂层的物相主要有高温稳定相金红石及锐钛矿;微弧氧化处理提高了TA7钛合金的自腐蚀电位,降低了腐蚀电流密度,石墨颗粒的加入进一步提高了自腐蚀电位,降低了腐蚀电流密度,显著提高了微弧氧化涂层的耐蚀性。     

微弧氧化镁表面钙磷生物涂层的制备及性能

为改善镁合金的骨植性能,采用微弧氧化处理和电沉积钙磷涂层相结合的方法在纯镁表面制备具有生物活性的复合涂层,研究了复合涂层在模拟体液和细胞培养液中的组织结构演化、腐蚀行为、骨形成能力和细胞粘附行为。 微弧氧化镁表面沉积的钙磷相为二水合磷酸氢钙(DCPD)。 电沉积过程中 DCPD 优先在微弧氧化层的通孔和放电通道处形核、随后长大并覆盖微弧氧化层而起到封孔作用。 涂覆后镁的低频阻抗模值在浸泡初期超过了 10⁵ Ω·cm² ,且在 120 h 内基本保持稳定;腐蚀电流密度与纯镁相比下降了约 3 个数量级,复合涂层显著地提高了镁的耐蚀性。 复合涂层在模拟体液和细胞培养液中均表现出了诱导羟基磷灰石(HA)沉积的能力,在细胞培养液中浸泡 14 d 后涂层表面出现球状类骨 HA 组织;细胞黏附试验中,活细胞几乎黏附在整个涂层表面,表现出良好的骨形成能力和细胞活性。     

Al2O3微粉添加量对镁合金微弧氧化膜特性影响研究

为了研究添加Al₂O₃微粉对AZ31A镁合金微弧氧化膜特性影响,在不同浓度Al₂O₃微粉电解液中对其进行了微弧氧化处理。利用扫描电镜(SEM)观察微弧氧化膜形貌,能谱仪(EDS)分析了膜层表面Ca、Mg、O、Al元素分布,X射线衍射仪(XRD)分析了相组成,测定了膜厚、硬度和氧化液中Al₂O₃表面电荷,讨论了掺杂改性机理。结果表明,加入Al₂O₃微粉后,氧化电压随Al₂O₃添加量增加先增加后降低;氧化膜表面孔洞数量和尺寸减小,膜层表面Ca元素分布逐渐减少,成膜效率降低,膜层致密度和表面疏松层硬度提高,氧化膜主要由MgO和MgO₄等相组成。     

超高频脉冲电流作用下纳米Al2O3颗粒对Mg-Gd-Y-Zr合金微弧氧化涂层的影响

目的 进一步提高Mg-Gd-Y-Zr合金微弧氧化涂层的耐腐蚀性能。方法 采用超高频微弧氧化技术在含有Al2O3纳米颗粒的溶液中制备了微弧氧化涂层。利用扫描电子显微镜(FESEM)、能谱仪(EDS)和X射线衍射仪(XRD)对微弧氧化涂层的表面形貌、截面形貌、成分和晶体结构进行分析。利用极化曲线和电化学阻抗谱(EIS)测试了涂层的耐腐蚀性能。结果 频率由0.5 kHz提升至20 kHz后,涂层表面放电孔洞面积由0.07~24.4 μm²降低至0.08~6.3 μm²,涂层的孔隙率由6.47%减小至3.35%。Al2O3纳米颗粒的添加使超高频涂层表面形成大量自封闭孔洞结构,进而进一步降低了涂层表面的孔径面积(0.1~ 4.63 μm²)和孔隙率(0.97%)。极化试验表明,提高频率至20 kHz,涂层的自腐蚀电流密度由4.7×10^‒6 A/cm²降低至4.7×10^‒7 A/cm² ,添加 Al2O3纳米颗粒,涂层的自腐蚀电流密度进一步降低至1.7×10^‒7 A/cm²,表明其耐蚀性能显著提高。阻抗谱显示,20 kHz-Al涂层具有最大的阻抗,说明该工艺可有效提高微弧氧化涂层的耐蚀性能。 结论 超高频可有效降低放电孔洞尺寸,提高微弧氧化涂层的致密性,改善涂层的耐腐蚀性能。超高频与Al2O3纳米粒子的协同作用使涂层表面形成自封闭孔洞结构,进一步提高微弧氧化涂层的致密性和耐腐蚀性能。     

可用于NdFeB永磁体表面保护的锌铝膜涂层技术

介绍了一种可用于NdFeB永磁体表面保护的涂层技术──DACROMET（达可乐－锌铝膜），该技术最突出的优点是无环境污染，耐蚀性、耐氢脆优异。初步实验证明，锌铝膜用于粘结NdFeB永磁体效果较好，用于烧结NdFeB永磁体很好，优于电镀锌和电镀镍．     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.