铝基准晶的研究进展

概述了铝基准晶态合金的形成机理,其形成存在着相似性原则,具有电子浓度特征.分析了铝基准晶合金的组织与相变特征,铝基准晶的生成通常为包晶、包析反应,其长大速度较慢.综述了铝基准晶合金的性能,铝基准晶具有高的硬度、高的弹性模量及高的强度,室温下塑性小,表现为脆性;铝基准晶具有优良的抗腐蚀性能;铝基准晶具有低摩擦因数和抗摩损的特征.对铝基非晶合金的应用进行了评述.     

高性能超细、纳米硬质合金及其制备过程中的关键技术问题

介绍了超细、纳米硬质合金的国内外研究、生产以及市场情况,主要应用领域,硬度、抗弯强度、断裂韧性、热硬度、热导率等力学、热物理性能和使用性能特点,湿磨过程中的研磨与分散、混合料制备过程中的控氧、粉末成形、烧结过程中WC晶粒长大的控制和粉尘控制等合金制备过程中存在的关键技术问题以及解决这些问题的主要途径.     

Melt metal sheet breaking mechanism of close-coupled gas atomization

The gas atomization is the process that a liquid mass is disintegrated into a collection of liquid melt droplets by the impact of high velocity gas stream and solidified into metal particles. However, the liquid melt sheet breaking mechanism has not been fully understood. So the experimental research was carried out under the condition of lower melt superheat. The results reveal that there are three approaches about melt metal sheet＇s breakage： from the edges of sheets, from inner surface of sheets, and disrupted by other droplets and sheets. The approach of melt sheet breakage is dependent on its thickness. The thicker sheets （above 25μm） are disintegrated mainly by the way of droplet＇s departing from edges, and the thinner sheets （below 10 μm） are chiefly breaking from the inner surface.     

不同服役条件下冷凝器白铜管的腐蚀特性

采用拉伸力学性能测试、扫描金相-微区成分分析和X射线衍射物相分析对冷凝器BFe-30-1白铜管服役前后和不同服役条件下管内壁的腐蚀特性进行了观察和分析.结果表明:白铜管服役前的组织性能符合国家标准GB/T 8890-1998的要求;新管镀膜后使用1.5 a的白铜管内壁出现相对较厚的不均匀疏松沉积层,去除沉积层后,白铜管内壁未见明显腐蚀现象;运行0.5 a后镀膜再使用2 a的白铜管内壁也未见沉积物层,但可观察到明显的点蚀坑和少量鼓包状腐蚀产物,说明白铜管镀膜后再使用比使用一段时间后再镀膜的耐腐蚀性能要好;由于点蚀坑内腐蚀产物中发现了含量较高的CuS和CuCl,说明循环冷却水中硫元素和氯元素参与了腐蚀过程.     

精心策划加速实施 精诚团结创新运作 奋力夺取《六届会》筹备工作的全面胜利！——在“《六届会》（湖南片）筹备工作研讨会”上的讲话 黄伯云（二00六年十月二十六日，湖南长沙）

为搞好《第六届中国功能材料及其应用学术会议》（简称《六届会》）的包括组织、宣传、征文、审稿等在内的各项筹备工作，今天，我省从事功能材料研究、开发与教学的部分知名专家、教授，在百忙中抽出时间莅临我校出席“《六届会》（湖南片）筹备工作研讨会”，对此，我代表中南大学，代表中国仪表材料学会、《功能材料》、《功能材料信息》期刊编委会、《六届会》组织委员会，对各位的光临表示热烈的欢迎和由衷的感谢！     

气氛对硬质合金MIM成形坯脱脂预烧结的影响

对比研究了硬质合金MIM成形坯在电解H_2或高纯度N_2气氛下脱脂预烧结的特性。研究结果发现:2种气氛下脱脂后的制品都会发生脱碳现象,但是脱碳程度不一样,高纯N_2气氛脱脂的脱碳程度较小,其脱碳是由于样品中的C与O相互反应;电解H_2气氛下的脱碳由气氛的露点决定。高纯N_2气氛脱脂预烧与电解H_2气氛脱脂预烧相比,样品的收缩大、孔隙度小、预烧结效果好。     

Prediction of powder characteristics of uniform NiO precursor prepared by homogeneous precipitation

Uniform NiO precursor particles were prepared by homogeneous precipitation in the presence of urea. Optimal discrimination plan, one of the chemical pattern recognition techniques, was applied to analyze the experimental data and the quantitative relationships among the process parameters and powder characteristics of the obtained particles were determined. It proves that the model fits well with the experimental results and it is quite effective to guide the process design. Based on the above results, an improved La Mer model and the reasonable formation mechanism of the particles are proposed.     

Syntheses, characteristics and fluorescence properties of complexes of terbium with benzoic acid and its derivatives

The binary complexes of terbium with benzoic acid and its derivatives (phthalic acid, iso-phthalic acid, oaminobenzoic acid, salicylic acid, sulfosalicylic acid) were synthesized and their compositions were identified by elemental analyses. UV, IR of the complexes were investigated. The UV spectra indicate that the complexes‘ ultraviolet absorption is mainly the ligands‘ absorption, but the location of peak drifts. The IR spectra show that the IR spectra of complexes are different from those of free ligands, and the band at 400 - 500 cm^-1 , due to the stretching vibration of Tb--O, is absent for free ligands. The fluorescence properties were investigated by using luminescence spectroscope, the results show that all the six complexes of terbium exhibit excellent luminescence, due to the transition from the lowest excited state ^5D4 to ^7F ground state manifold, the complexes of terbium with sulfosalicylic acid have the strongest fluorescence intensity, and is stronger than o-aminobenzoic acid-terbium, whose fluorescence intensity is regarded as the strongest one in the literature, and even stronger than some phosphor of terbium.     

Influence of melt superheat on breakup process of close-coupled gas atomization

In close-coupled gas atomization（CCGA）, the influences of melt superheat on breakup process are fundamental to obtain desired or finer powder. Based on a series of Cu atomization experiment under different superheating conditions, the influences of melt superheat on breakup process were studied. Experimental results indicate that as the melt superheat is increased to 150, 200, 250 and 300 K, the mean particle size （D50） decreases consequently to 34.9, 32.3, 30.9 and 19.7 μm. Theoretical analysis reveals that the primary breakup and secondary breakup processes are close coupled, and the melt superheat radically influences the melt properties, and plays a crucial role on governing the filming process of primary breakup and the atomization modes of secondary breakup. There exists a strong nonlinear decrease of contact angle of melt to nozzle orifice wall when the superheat is increased fi＇om 250 K to 300 K, leading to a marked fall of the film thickness formed in primary breakup, and D50 of copper powders is therefore sharply reduced. However, the log-normal distribution feature of particle size has not been substantially improved.     

固体火箭发动机喷管用C/C复合材料的研究进展

C/C复合材料已成为固体火箭发动机(SRM)最理想的喷管材料。综述了国内外SRM喷管用C/C复合材料的研究进展、应用状况以及烧蚀性能的研究状况,展望了今后C/C复合材料喷管的发展趋势。