热等静压对粉末冶金TiAl 合金显微组织和相成分的影响

采用元素粉末Ti,Al,Cr,Nb为原料,通过对Ar气保护下的高温热压工艺,制备出了高致密度的TiAl基合金。通过光学显微术、SEM、EDAX、XRD技术分析了热等静压对材料的显微组织和相成分的影响。结果表明,在1200℃和1300℃下分别热压1h后可以得到显微组织细小的TiAl基合金,Cr元素的分布比较均匀,但是存在一些Nb元素的扩散不完全现象。通过后序热等静压工艺可以改善合金元素在显微组织中的均匀分布。     

羟基氧化镍的研究进展

羟基氧化镍作为锌镍电池和MH-Ni电池的正极活性物质已经逐步成为电池材料领域一个新的研究热点。综述了锌镍电池和MH-Ni电池的工作原理及羟基氧化镍的制备、结构、电性能;分析了羟基氧化镍的放电比容量及Ni(OH)2/NiOOH电极的可逆电极电势;围绕高放电比容量、自放电率低、高密度羟基氧化镍的发展前景,建议了今后的研究方向。     

Sintering of the NiFe2O4-10NiO/xNi Cermet

The sintering behavior of NiFe2 O4-10NiO/xNi cermet which was used as the most prospective inert anode materials for aluminum electrolysis was studied by examining the effects of raw powder particle size, sintering temperature, and the contents of Ni. The results show that fine particle size enables the powder to have high driving force for sintering. High temperature is beneficial to densification, but the ultra-high temperature does harm to the improvement of the density. The samples of NiFe2O4-10NiO/SNi has the highest relative density of 97.28 % when it is sintered at 1 350 ℃, but it decreases to 95.23 % when sintered at 1 400 ℃. Low addition of Ni has a great help to the sintering of NiFe2 O4-10NiO matrix. When the samples are sintered at 1 350 ℃ and the mass fraction of Ni is 5%, the highest relative density is gained, but the density decreases with the further increase of Ni contents. The low density of the sintered samples of NiFe2 O4-10NiO/17Ni is attributed to the high volume fraction of pores.     

Electrodeposition of Ni-Co-Fe2O3 composite coatings

Ni-Co-Fe₂O₃ composite coatings were electrodeposited using cetyltrimethylammonium bromide (CTAB)-modified Watt’s nickel bath with Fe₂O₃ particles dispersed in it. The effects of the plating parameters on the chemical composition, structural and morphological characteristics of the electrodeposited Ni-Co-Fe₂O₃ composite coatings were investigated by energy dispersive X-ray (EDS) spectroscopy, X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The results reveal that Fe₂O₃ particles can be codeposited in the Ni-Co matrix. The codeposition of Fe₂O₃ particles with Ni-Co is favoured at high Fe₂O₃ particle concentration and medium stirring, and the deposition of Co is favoured at high concentration of CTAB. Moreover, the study of the textural perfection of the deposits reveals that the presence of particles leads to the worsening of the quality of the observed 〈220〉 preferred orientation. Composites with high concentration of embedded particles exhibit a preferred crystal orientation of 〈111〉. The more the embedded Fe₂O₃ particles in the metallic matrix, the smaller the sizes of the crystallite for the composite deposits.     

Fabrication and mechanical properties of FeAl/TiC composites

1　INTRODUCTIONOver the past few decades, considerable inves tigations have been carried out to identify alterna tive binders for cermets in order to improve theirmechanical properties and also to overcome certainshortcomings, such as high cost and density, lowoxidation and corrosion resistance, and environ mental toxicity[1, 2]. Iron aluminides are of particu lar interest due to their low cost and density, highspecific strength, environmental friendliness andexcellent oxidati…     

铸轧铝的组织、性能及工艺新进展

评述了铸轧铝带坯的组织特征与性能特点，综述了双辊连续铸轧铝带坯生产工艺的发展历史和现状以及当今世界的发展动向。分析了我国铝带坯的生产在世界上的地位以及存在的问题。     

胞状结构NiFe2O4/Ni金属陶瓷的制备及性能

采用结构功能化设计理念,使用共挤压成形工艺制备具有胞状结构的NiFe2O4/Ni金属陶瓷坯体。试样在1 350℃的氮气气氛下进行烧结。结果表明,在构造胞状结构过程中,有机添加剂起到了粉末流动载体及对坯件的保形作用。对所得试样导电性能及力学性能的分析结果表明,与同等Ni含量NiFe2O4/Ni均匀体试样相比,胞状结构试样的电导率有显著提高且与富Ni层中的金属含量有关;虽然胞状结构材料的抗弯强度高于同等金属含量NiFe2O4/Ni均匀体,但随着富Ni层金属含量的提高材料的抗弯强度呈下降趋势。     

泡沫镍基Ni-S-Co镀层的梯度电沉积

以泡沫镍为基体,通过提高镀液中硫脲浓度的方法梯度电沉积制备了非晶态Ni—S—Co合金镀层电极。用SEM观察镀层表面形貌,面能谱测试镀层的结果表明,随着镀液中硫脲浓度的升高,镀层中S元素的含量逐渐提高,钴元素的含量逐渐降低,镀层由内到外形成了S元素含量不断增加的梯度结构。电化学测试结果表明,与非梯度镀层相比,梯度镀层的极化电位在各电流密度条件下都显著低于非梯度镀层电极。     

燃烧合成制备生物陶瓷涂层的开发研究

简要介绍了燃烧合成表面涂层技术这种新兴表面改性技术的原理和应用,并阐述了本单位采用此法在生物陶瓷涂层制备方面的开发和研究.结果表明,燃烧合成制备生物陶瓷涂层有利于提高材料的生物活性和生物相容性,具有较大的应用前景.