化学镀法制备Cu/Al2O3复合粉体及其烧结行为

为了解决颗粒增强铜基复合材料中颗粒与铜基体相容性的问题,采用化学镀法使得颗粒表面金属化,通过XRD、SEM、EDS等技术研究了Al2O3纳米粉化学镀铜的工艺,并对Cu/Al2O3复合粉体的烧结行为做了初步探讨.结果表明:Al2O3粉前处理工艺、镀液的各种成分都对粉体表面铜的含量有影响,通过改变装载量可有效控制粉体表面Cu含量.实验中确定了最佳的镀覆工艺,并得到了颗粒较为弥散的Cu/Al2O3复合粉体烧结体.     

纳米Al2O3p化学镀铜复合粉末的烧结致密化

化学镀是制备纳米颗粒增强金属基复合材料的有效方法.对纳米Al2O3p化学镀铜粉末的烧结致密化特点进行了研究,分析了化学镀粉末的预处理、成型压力、烧结温度、保温时间、复压复烧工艺等对致密化的影响.在优化各影响因素的情况下,对Al2O3含量为10%的化学镀铜粉末采用常规粉末冶金工艺得到了相对致密度达94%的试样.     

Cu包覆纳米Al_2O_3复合粉体的化学镀法制备

纳米Al2O3的力学性能优异,是一种理想的Cu基纳米复合材料的增强体,然而其与Cu基体的润湿性较差。为了改善其与Cu基体的润湿性,增强界面的结合力,通过化学镀工艺在其表面镀Cu,并采用SEM、TEM、XRD和EDS系统研究了镀液中络合剂及还原剂类型、镀液温度及施镀条件等重要因素对化学镀过程、镀膜质量的影响,进而优化了施镀工艺,获得了粒径均一、分散良好的Cu包覆纳米Al2O3复合粉体,为A12O3/Cu纳米复合材料的制备打下了良好的基础。     

激光辐照诱导氧化铝陶瓷基板表面化学镀铜

采用激光辐照处理对Al2O3陶瓷基板进行预处理,经过超声波辅助化学镀在Al2O3陶瓷基板表面成功制备了化学镀铜层。利用场发射扫描电子显微镜(FE-SEM)和能谱(EDS)研究分析了激光辐照预处理前后Al2O3基板表面形貌和Al2O3基板化学镀铜表面以及截面形貌,划痕形貌,并与传统贵金属Pd活化预处理化学镀铜进行对比。试验结果表明:激光辐照处理后Al2O3基板表面出现了大量的微孔和纳米级颗粒凸起,这些表面缺陷易于吸附外来物质成键,实现化学镀铜过程,其中镀层与基底也有较好的结合力;与传统Pd活化预处理化学镀铜对比发现,激光辐照处理避免了繁琐的工艺和贵金属带来的污染,同时生成的化学镀铜层颗粒与颗粒之间融合更好。     

Al2O3陶瓷表面化学镀铜工艺及其低温连接

进行了Al2O3陶瓷表面的化学镀铜处理,制定了前处理流程.研究了硫酸铜浓度、甲醛浓度、施镀温度、施镀时间等对镀层沉积速率的影响,对镀层进行了金相分析,在此基础上得到化学镀铜的优化工艺.进行了镀铜后Al2O3陶瓷低温钎焊工艺试验,研究了不同化学镀工艺条件对接头组织及力学的影响.结果表明,在试验条件下,随着焊接温度升高,接头致密度变差;焊接时间增加,焊缝宽度也增加;硫酸铜,甲醛浓度增加,镀层厚度增加,相对影响了钎焊焊缝宽度和质量.     

化学镀法制备纳米Ni-Al2O3复合粉体的研究

氧化铝陶瓷是应用最为广泛的一类陶瓷,但其自身的特点限定了它的应用.为了获得性能更加优良的氧化铝陶瓷,采用化学镀方法对平均粒径200nm的Al2O3粉末进行化学镀镍,制备出了纳米级的Ni-Al2O3复合粉体,并筛选出了合适的前处理和化学镀工艺.通过扫描电镜及能谱分析结果可知,采用该化学镀工艺,能在Al2O3颗粒表面得到表面形态较好的均匀的镍镀层.镀层主要由Ni相和P相组成,其镀层含磷量为9.94%.改良后的复合粉体,其性能将得到很大的改善.     

镍包覆氧化铝增强铁基复合材料的界面行为及其耐磨性

采用化学沉积法在Al2O3表面制备了Ni镀层,将所制得的Ni包覆Al2O3颗粒(Al2O3P@Ni)作为铁基体的增强颗粒,采用SPS法制备了镀镍氧化铝增强铁基复合材料(Al2O3p@Ni/Fe).通过优化化学镀工艺,使得Al2O3表面被Ni层均匀覆盖.Ni镀层呈典型的花椰菜状结构,尺寸为1～4 ～μm,施镀过程中镍首先...     

化学镀Ni-P-W/Al2O3 复合镀层与NdFeB基体的结合强度研究

采用化学镀方法,在NdFeB磁性材料表面施镀Ni-P-W/Al2O3复合镀层,观察了镀层表面的微观形貌,测定了镀层的相组成,并且对基体与镀层间的结合强度进行了测试.结果表明:形成了胞状交叠的致密Ni-P-W/Al2O3复合镀层,纳米Al2O3颗粒弥散分布于Ni-P-W合金中;Al2O3颗粒与Ni-P-W共沉积有利于提高镀层与基体间的结合强度,镀液中Al2O3的质量浓度为5～10 g/L时,基体与镀层间的结合强度最好.     

表面活性剂对Ni-P-Al2O3复合镀层性能的影响

目的 改善Ni-P-纳米Al2O3复合镀层的均匀性,提高其耐蚀性能.方法 采用化学镀法在Q235钢表面制备Ni-P纳米Al2O3复合镀层,分析纳米Al2O3添加量(0～10g/L)对镀层形貌的影响.施镀过程中选用不同种类的表面活性剂来分散纳米Al2O3,通过XRD分析镀层的相组成,采用SEM、EDS研究镀层形貌和成分,通过测量施镀前后纳米Al2O3的Zeta电位来研究非均一镀液的稳定性和纳米粒子的分散性能,利用电化学阻抗手段研究镀膜样品在3.5％NaCl水溶液中的耐蚀性能,从而分析镀液中表面活性剂的种类和用量对复合镀层的影响.结果 随着镀液中纳米粒子添加量的增加,镀层中Al2O3含量先增加后趋于稳定,同时镀层表面纳米Al2O3团聚现象也随之加剧.添加一定量表面活性剂之后,镀层变得均匀,纳米粒子团聚减少,其中阳离子表面活性剂(十六烷基三甲基溴化铵)在低浓度下就能对纳米Al2O3分散产生显著作用,而阴离子表面活性剂(十二烷基苯磺酸钠)需在较高浓度下才能达到相似效果.结论 当镀液中阴离子表面活性剂用量为1.25cmc,Al2O3添加量为6g/L时,镀层最为均匀,且样品在3.5％NaCl水溶液中耐蚀性能最好.     

离子注入辅助Al2O3陶瓷表面化学镀镀层特性研究

用金属离子源在96Al2O3陶瓷表面注入不同能量和剂量的Ni离子,然后在镀液中进行化学镀铜.用扫描电镜、卢瑟福背散射能谱和X光电子能谱技术对注入层和镀层进行分析研究.结果表明:Ni离子注入可作为一种新的活化工艺,辅助Al2O3陶瓷化学镀铜;注入参数对后续化学镀覆有显著影响,注入获得表面Ni浓度高的镀覆效果较好,应选用低能量进行高剂量注入;试验条件下优选工艺参数为15keV,2.2×1017ions/cm2,该条件下开始化学镀铜的孕育期仅为45s,镀速达到52.43nm/min,镀层表面粗糙度为0.317μm,所得化学镀铜层均匀、致密,与基体结合紧密.     

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。     

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.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

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.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

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.     

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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