难熔金属Zr中痕量杂质的ICP-MS测定

研究了难熔金属Zr中痕量杂质的ICP_MS分析方法 ,系统考察了ICP_MS中介质影响 ,多原子离子干扰 ,基体影响及不同内标的校正作用等 ,并试验了难熔金属Zr的消解方法 ,设定了最佳工作参数 ,标准加入回收率为 (10 0±10 ) % ,方法的检出限 <0 92mg/L ,精密度RSD <5 % ,样品分析结果准确可靠。     

放电等离子烧结在金属-陶瓷复合材料制备中的应用

放电等离子烧结(SPS)是一种材料制备新技术。近年来，放电等离子烧结技术已成功用于制备金属-陶瓷复合材料，且在制备难熔化合物、纳米材料、梯度功能材料和开发新金属-陶瓷复合材料方面有其独特的优越性。综述了金属-陶瓷复合材料放电等离子烧结的最新研究进展，指出了放电等离子烧结金属-陶瓷材料的优缺点，并对今后的研究作了展望。     

WC—Co硬质合金的热处理强化

硬质合金是以难熔金属碳化物(主要是WC、TiC)为基本成分和以铁族金属(主要是Co,其次是Ni)为辅助成分,采用粉末冶金方法制成的。难熔金属碳化物具有很高的硬度,而铁族金属具有足够强度、韧性,且二者可很好的结合,所以自然硬化的硬质合金具备高硬度、高耐磨性和一定的韧性。由于硬质合金具有一系列优良的性能,在工具材料、耐磨材料、耐高温和耐腐蚀材料中占据相当重要的地位。近年来人们发现,烧结后自然硬化的WC-Co硬质合金再进行适当的热处理,合金性能得到进一步改善,合金使用寿命显著提     

密闭增压溶样罐的设计

介绍了一种密闭增压溶样罐的设计和制作。此溶样罐可在微波炉，高温炉及干燥箱中加热。加速样品的分解。溶样带有压力指示装置，可有效避免泄露和爆炸事故的发生。     

电子束单晶炉放电问题分析及解决办法

针对电子束区难熔金属单晶生长过程中出现的放电问题,分析了其原因,并采取了相应的措施,有效的解决了放电问题。通过对高压灯丝电源系统增加保护措施,防止了放电对电源部件的损坏。根据电子束悬浮区域熔炼法的特点对阳极与电子枪之间的短路现象增加了防护系统,有效的消除了短路带来的不利影响,为制备难熔金属单晶提供了保障条件。     

等离子喷涂技术及其应用

一、概述等离子喷涂技术是五十年代末期开始发展起来的。它和其它喷涂方法(氧乙炔火焰喷涂、金属电弧喷涂)相比,可以熔化一切难熔金属和非金属粉末,使普通材质的零件表面获得一层具有耐磨、耐腐蚀、耐高温等各种不同性能的涂层。它可以达到提高机器设备零部件的表面质量、延长使用寿命、修     

ICP-AES法测定塑料中金属含量的前处理对比

针对塑料中金属含量的测定,采用4种样品前处理方法在等离子发射光谱仪上进行测定及对比研究,确定了不同元素及含量的溶样方法,对分析谱线、发射功率等进行了选择,测试结果回收率为81.2~112%。     

微波技术在生物样品预处理中的应用

微波溶样技术是近年来发展的一种崭新的极有前途的溶样技术。本文采用微波消解溶样，利用原子发射光谱法(ICP-AES)对国外多种生物样品进行微量元素全分析，进行了消化条件的选择，并利用国家一级标准物质潞党参GBW09501和贻贝GBW08571验证了方法的准确度，其测定值与标准值吻合较好，表明高压微波消化法具有消解完全、迅速、结果准确的优点。     

锆铪的ICP-AES分析方法研究及应用

稀有难熔金属铌铪合金,铌钽钨合金及锆钨钼化合物等材料具有特有的高熔点,高强度,高硬度特点,应用于航天航空等领域,其成分及难熔金属杂质分析是化学分析中难度较大的课题,在实际分析中令分析工作者感到棘手。     

真空扩散焊技术的应用

近年来,材料科学发展很快,在工程上异种金属、金属和非金属材料之间的连接日益增多,尤其是难熔材料的熔化焊,质量难于保证;多数工件结构复杂又要求高精度的焊件,扩散焊接技术就是应这种条件而得到发展起来的。近三十年来,随着真空技术的发展引用到焊接之后而发展起来的真空扩散焊,因其焊接质量优于其他各种焊接方法,因此博得了世界各国的高度重视。     

经验模式分解的改进及其在水轮发电机组振动信号分析中的应用

经验模式分解可以将非线性、非平稳信号分解为有限个固有模式函数,在故障诊断中这些固有模式函数常常就是故障信号。但端点效应和分解终止条件的不当使其在分解过程中出现假频,限制了其应用。提出采用可变长极值镜像拓延法,对原信号两端包络进行拓延,有效地消除了端点效应;并提出在分解过程中采用不同的结束标准,使程序在适当的时候结束,提高了分解精度和速度。最后,将该方法应用于水轮发电机组振动信号分析中,取得了满意的效果。     

Very low voltage sputter coating

Very low voltage sputter coating, in the range 175–300 V, has been used to produce finely structured thin films of noble and refractory metals for use in high resolution scanning electron microscopy. There is a marked diminution in the particle size with a decrease in cathode voltage. Although the sputtering times are longer than with conventional diode sputter coating, such times are shorter than those required to produce similar films by Penning or ion-beam sputtering. The refractory metals produce films which are fine grained and suitable for high resolution studies. The method has been used to sputter coat thin layers of aluminium. All attempts at sputtering carbon have failed; the reasons for this are discussed in some detail.     

A mass-spectrometer complex for measuring the isotopic composition of the difficult-to-ionize metals

A mass-spectrometer complex based on a Mι 1320 commercial device and intended for measuring the isotopic composition of difficult-to-ionize refractory metals by the Re-Os method is described. The results of isotope-ratio measurements of the OsO₂ standard by recording the ion currents with a secondary-electron multiplier are presented.     

Adhesion of Rare Earth Metals

Results of adhesion tests performed on yttrium (Y), as well as four rare earth metals, samarium (Sm), gadolinium (Gd), dysprosium (Dy), and holmium (Ho), are reported. A modification of the twist-compression bonding method was used to obtain the coefficients of adhesion. Low adhesion values for the above metals were obtained as expected on the basis of the crystal structure considerations. A proposal is made to apply the atomic “size-factor” criterion to the prediction of adhesion properties of dissimilar metals. An illustration of the method is given in terms of adhesion of iron to the above mentioned metals.     

Weight minimization of a speed reducer by heuristic and decomposition techniques

Discrete combinatorial optimization techniques (heuristics)[1–5] have been extended for optimum synthesis of medium-and-large-scale mechanical systems [6,7]. Decomposition techniques based on the kinematic structure of mechanisms have been developed. Other decompisition methods have been previously outlined[7]. The decompositon techniques were then combined with a heuristic search to obtain efficient optimization method for large-scale mechanical systems. The optimization scheme has been applied for weight minimization of a speed reducer. The results obtained by the techniques, which have been developed, indicate that these methods are more efficient than various schemes, such as adaptive optimization approach, random-gradient technique, and Monte-Carlo method. all previously employed for weight minimization of a speed reducer.     

Application of atomic-force microscopy when measuring microhardness of thin coatings by scratching

The method is proposed for determining the microhardness of thin coatings by scratching. Atomic force microscopy was applied to determine the scratch width and the optimal load on the indenter. Combined coatings 4 μm thick based on Ti, Cr, Mo₂N, and alloy ZrHf obtained by the combination of electric-arc evaporation and ion nitridizing were studied. The combined coatings are shown to have better micromechanical characteristics compared to the nitride coatings deposited by the electric-arc evaporation of these refractory metals and alloys.     

Determining coefficients of friction in compaction of refractory metal powders

Knowing the coefficients of friction in tool compaction of powders of metals and alloys allows one to rationally design technological equipment for manufacturing powder semifinished products experiencing minimal warping under vacuum or hydrogen sintering. This is of particular significance when consumable electrodes are produced from powders of refractory metals being compacted as rather long fillets that are curved in sintering if any irregularities in the density in the cross section and in the fillet bulk are present. Both well-known and new methods are analyzed for finding the coefficients of friction in powder compaction, in particular in cylindrical containers. Stable and valid measurement results are shown to be unachievable. A new method for experimental determination of the coefficients of friction under powder compaction is described. It consists in comparing the force parameters of one- and two-sided compaction. This method allows finding the coefficient of side pressure and contact friction (on the cylindrical surface of the container) during the formation of briquettes of TsM-2A alloy with different concentrations of plasticizer and solvent. A positive effect of a plasticizer and negative one of a solvent on the coefficient of friction is stated.     

An Investigation of Seal Materials for High-Temperature Application

Novel rotating seal materials were developed by powder metallurgy techniques for potential aircraft applications at high speeds and high temperatures.

A systematic wear study without lubrication included several commercially available materials and the following types of experimental materials: (a) pure refractory hard metals, (b) binary alloys of refractory hard metals bonded with nickel and, (c) ternary alloys of refractory hard metals bonded with nickel and infiltrated with silver.

Two ternary alloys, containing nickel bonded WB or CrN and infiltrated with silver, showed superior wear qualities against either tool steel or a nickel—chromium—iron alloy at a sliding speed of 29,000 ft/min under a 14 lb/in² load and at ambient temperatures as high as 1300 F. A commercial titanium carbide composition showed excellent wear characteristics in contact with an identical composition at a sliding speed of 14,000 ft/min under a 16 lb/in² load and at an ambient temperature of 1050 F.     

Oxidation Characteristics of MoS2 and Other Solid Lubricants

Thermogravimetric oxidation data are presented for fifteen refractory metal dichalcogenides. Interpretation of these data is supported by oxidation thermograms of the chalcogens and the refractory metals and by X-ray diffraction analysis of the oxidized products. The effects of humidity, heating rate, and particle size on oxidation of the dichalcogenides are presented. Thermogravimetric analysis is shown to be helpful in detecting impurities, such as unreacted elements, in commercial samples. Some dichalcogenides are shown to retain the same relative oxidation stability, when bonded in thin films with a ceramic, as for pure powder samples. A table is presented summarizing these oxidation characteristics together with information from the literature on crystal structures, electrical resistivities, and densities.     

微波消解原子吸收法测定米粉中铁含量

采用湿法消解技术溶样,用原子吸收（AAS）法测定米粉中铁的含量。通过对微波程序的研究,建立米粉、奶粉等的微波消解方法。该方法与传统马弗炉高温灰化消解方法及湿法消化比较,具有准确、简便、安全、省试剂、污染少、消解完全等优点。方法回收率为96%～106%。RSD（n=7）均小于2%。实际样品对比分析结果表明,方法具有良好的准确度,适于奶粉、米粉、豆粉等食品的快速分析。