稀土元素对化学镀镍的影响

研究了３种稀土元素Ｌａ，Ｎｄ和Ｅｕ对化学沉积过程的影响。结果表明，于化学镀镍液中添加１０＾３％Ｌａ可使化学沉答速度增大；Ｎｄ也可加快化学沉积速度。而Ｅｕ却使化学沉积速度降低。添加适当浓度的稀土元素，还要改善化学镀镍层的耐磨性和抗腐蚀性能。     

微机在金属材料工程中的应用

微机在材料工程方面比其它领域起步要晚,国内近几年才开始使用。微机科技应用可分为4个方面:科学计算,工程测控,统计管理和人工智能。本文仅对前两方面在材料工程上的应用作一简单介绍。     

金属材料展望

对金属材料的研究开发和工业发展作了展望,内容包括材料研究与开发的总形势;材料工业的前景和传统金属材料的作用以及材料工业发展的政策和策略。     

1992年金属材料动向

1 热处理强化热轧钢件日本钢铁公司为汽车车架和连接件研制了一种含1.0～1.6%Cu的超低碳(0.0013%C)钢板。这种称为Cu-High Ten的新钢种,可在低强度状态下冷成形。在轧制供货状态下,铜保持在过饱和固溶体内,这时钢的抗拉强度约为400MPa。其成形性能类似同样强度的普通碳钢。零件成形后,经475～675℃时效处理10min,由于铜沉淀硬化,抗拉强度可增大到600MPa。该钢种具有良好的可焊性。     

金属材料发展动向

尽管其它材料领域有很大发展,但是金属工业远非停止不前。以钢铁工业为主导,金属生产行业正不断开发新工艺和新材料,从而有助于保持现有市场并开辟新的市场。一般钢材强烈竞争的世界钢铁工业都把重点放在能提高产品质量和降低成本的任何工艺改进     

稀土元素对中碳钢组织、力学性能和渗氮的影响

在一种中碳钢中通过添加微量稀土元素,研究稀土微合金化对钢的微观组织、力学性能以及在渗氮热处理条件下对渗层的影响.结果表明,添加稀土后,长条状的MnS夹杂和粗大块状的A12O3转变成小球状的稀土硫氧化物夹杂;铁素体的含量降低,并促进细小片层结构的珠光体形成;冲击性能提升126％以及塑性提高10％;渗氮处理后,添加稀土能显...     

金属材料

洛阳将建全国最大的钨钼基地，株硬第一款特大型硬质合金平剪刀模市场受捧，日本开发出新型粉末高速钢，Mott公司宣布在北京设立首个海外销售公司，攀钢开发出含钒喷熔合金粉     

金属材料信息科学

作者倡导建立的金属材料信息科学是以实验资料和“金属材料科学理论系统”为基础,以“合金系中特征原子序列工程”为先导,重点研究一般信息和目标信息的再生,信息的表示、变换、存储、传递、检测和施效等运行规律。它是实现新合金计算机辅助设计的前提,是21世纪现代金属材料科学的支柱之一。     

当今世界的金属材料市场预测

据报道,美国 Gorham 现代材料研究所投入相当大的力量完成了历时8个月之久的多用户市场调研计划,其结果颇为引人注意。现就其主要者介绍如下。铝化合物。因为这种化合物的天然脆性,加工时往往需要采用特殊的技术。据称,对铸造的镍铝化合物锭坯已经成功地进     

Stress corrosion cracking of rare-earth containing magnesium alloys ZE41, QE22 and Elektron 21 (EV31A) compared with AZ80

Stress corrosion cracking (SCC) of the high-performance rare-earth containing magnesium alloys ZE41, QE22 and Elektron 21 (EV31A) was studied using slow strain rate test (SSRT) method in air, distilled water and 0.5 wt.% NaCl solution. For comparison, the well-known AZ80 alloy was also studied. All alloys were susceptible to SCC in 0.5 wt.% NaCl solution and distilled water to some extent. AZ80 had similar SCC susceptibility in distilled water and 0.5 wt.% NaCl solution. ZE41, QE22 and EV31A had higher susceptibility to SCC in 0.5 wt.% NaCl solution than in distilled water. EV31A had the highest resistance to SCC compared to AZ80, ZE41 and QE22 in both distilled water and 0.5 wt.% NaCl solution. The fractography was consistent with (i) largely transgranular SCC (TGSCC) in distilled water for AZ80, ZE41 and QE22 and also for AZ80 in 0.5 wt.% NaCl solution, and (ii) a significant component of intergranular SCC (IGSCC) in 0.5 wt.% NaCl solution for QE22, ZE41 and EV31A. The TGSCC fracture path in AZ80, ZE41 and QE22 is consistent with a mechanism involving hydrogen. In each case, the IGSCC appeared to be associated with the second-phase particles along grain boundaries. For IGSCC of EV31A and QE22, the fractography was consistent with micro-galvanic acceleration of the corrosion of -magnesium by the second-phase particles, whereas it appeared that the second-phase particles had corroded itself in the case of ZE41 in 0.5 wt.% NaCl solution. The study suggests that rare-earth elements in magnesium alloys can improve SCC resistance significantly as observed in the case of EV31A. However, the SCC resistance also depends on the other critical alloying elements such as zinc (in ZE41) and silver (in QE22) and the microstructure.     

Ce掺杂对TbFeCo材料磁光性能影响的研究

采用射频磁控溅射方法制备了TbFeCo非晶磁光薄膜,并在TbFeCo中引入轻稀土元素Ce,测试了薄膜的磁光性能。研究了薄膜成分对其磁光性能的影响。结果表明;在TbFeCo薄膜中掺入少量Ce时,薄膜的磁光克尔角及矫顽力都有所提高,矩形度也增加了。但随Ce掺入量的增加,薄膜的磁光性能发生恶化,较好的掺杂在10.31?左右。     

Controlled synthesis of carbon-based alumina nanophosphors with tunable blue-green luminescence

Carbon-based alumina nanophosphors were prepared by a facile liquid process. The nanophosphors showed high photoluminescence properties, and tunable color emission from blue to green. The luminescent intensity and color were controlled by simply manipulating of polyethylene glycol and urea amounts, respectively. Oxygen deficiency, surface defects, and carboxylic impurities are considered to be possible emission mechanisms.     

Luminescence at 2.8 μm: Er3+-doped chalcogenide micro-waveguide

This paper reports the fabrication of luminescent optical rib/ridge waveguides made of erbium doped Ga-Ge-Sb-S films deposited by RF magnetron sputtering. Several fluorescence emissions of Er³⁺ ions from the visible to the middle infrared spectral domain were clearly observed within the films. The study of the ⁴I_13/2 level lifetime enabled development of a suitable annealing treatment of the films to reach the value of the bulk counterpart while the variation in surface roughness was limited, thus ensuring reasonable optical losses (0.7–0.9 dB/cm). Amplification experiments were carried out at 1.54 μm leading to complete characterization of the erbium-doped micro-waveguide with ∼3.4 dB/cm on/off gain. A demonstration of mid-IR photoluminescence from Er³⁺-doped chalcogenide micro-waveguide was recorded at ∼2.76 μm. The multi-luminescence from the visible to mid-IR generated using erbium doped chalcogenide waveguiding micro-structures might find easy-to-use applications concerning telecommunication technologies or on-chip optical sensors for which luminescent sources or amplifiers operating at different wavelengths are required.     

Pyroelectric properties of Pb0.88Ln0.08Ti0.98Mn0.02O3 (Ln=La, Sm, Eu) ferroelectric ceramic system

In this work, the pyroelectric properties of Pb_0.88Ln_0.08Ti_0.98Mn_0.02O₃ (Ln=La, Sm, Eu) ferroelectric ceramic system are studied. This type of ferroelectric ceramic presents high values of the following characteristics: dielectric constant, Curie temperature, electromechanical anisotropy, and high frequencies of operation, which make them useful for applications such as ultrasonic transducers in biomedical applications. The relationship between dielectric constant and temperature measurements as well as pyroelectric measurements using the technique of Byer and Roundy were performed. Values of the pyroelectric coefficient and figure of merit for infrared detector materials were obtained to use these ceramics in the detection of infrared radiation, laser power measurements, and solar energy technology.     

全球稀土永磁产业的发展近况

磁性材料,特别是永磁材料已成为信息社会高技术产业赖以存在的重要物质基础之一。它不仅广泛用于计算机、自动化、通讯、航天等高技术领域,在冶金、化工、机电、能源、交通等基础产业中也广为应用。它更作为各类家用电器的关键功能器件进八了千家万户。在当今信息社会中,可用永磁材料,特别是高性能永磁材料的生产能力和实际产量来衡量一个国家的经济发展水平和生活水平。本文旨在评述国内、外稀土永磁产业的发展近况。     

中国NdFeB磁体产业的10周年

中国NdFeB磁体的研制始于1983年,此后全国如此众多的大学和研究所均介入NdFeB磁体的研究与开发。与此同时,NdFeB磁体的生产也迅速增长。今天中国NdFeB磁体的产量仅次于日本,位居世界第二。本文评述中国NdFeB磁体产业的发展现状和前景,以作为我国NdFeB磁体产业10年历程的纪念。     

Dealloying by metallic melt

Dealloying, which commonly involves corrosion processes in aqueous solutions, is a promising technique for preparing functional nanoporous metals. While this technique is ideal for preparing nanoporous noble metals such as of Au, it is not readily applicable to less-noble metals. Here, we propose a novel dealloying method employing a metallic melt, instead of an aqueous solution, as the dealloying liquid for a preparing of nanoporous metals. An atomic interaction among alloy components and metallic melt causes specific component to dissolve out from the alloy solid into the melt with self-organizing nanoporous structure by the remaining component. The dealloying method can be applied for preparation of nanoporous less-noble metal such as of Ti for the development of functional materials such as fluid filters, gas absorption media, and biomaterials.