等离子发射光谱法同时测定电镀污泥浸出液中多种重金属的方法研究

采用醋酸缓冲溶液对电镀污泥样品进行浸提,建立电感耦合等离子体原子发射光谱法(ICP–OES)测定电镀污泥浸出液中铜、锌、镍、镉、铅元素的分析方法。研究了仪器的工作条件及影响检测方法的干扰因素和消除。在选定的条件下,线性相关系数均为0.9999,检出限为0.002～0.009mg/L,加标回收率为91.0%～101%,测定结果的相对标准偏差均在1.28%～3.08%(n=6)之间。该方法准确快速,可用于电镀污泥浸出液中多种重金属的含量测定。     

铑电镀液中铑含量不同测定方法的比较

铑作为一种贵金属,准确测定其在镀液中的含量非常重要.通过对铑的标准浓度溶液进行重量法、等离子体发射光谱法(ICP)、火焰原子吸收光谱法(FAAS)和改进后的FAAS(引入一个校正因子, 对FAAS测定方法进行了优化、校正)等不同方法的测定,比较了不同测定方法的适用范围和精确度.结果表明:对于杂质少的铑电镀液,宜采用重量法测定,其测定偏差在4%以内,硼氢化钠作为还原剂的重量法的测定偏差可控制在0.2%以内;对于杂质多的铑电镀液,用ICP,改进后的FAAS均能获得满意结果,相对偏差都小于1% .     

金矿地质样品分析中绿色化学法的应用

化学污染是金矿地质研究工作中所面临的一个现实问题。如何运用绿色化学方法,使金矿地质样品的分析更加简便、绿色且成本低廉成为国内外同行们需共同努力的方向。本研究就原子吸收光谱法(AAS)与电感耦合法(ICP-AES)相结合的绿色化学法在金矿地质样品分析中的应用进行阐述,以期能为业内提供新思路与参考。     

涂料中重金属的快速测定方法的研究

采用原子吸收光谱法并结合微波制样技术。测定涂料中有毒重金属元素。对影响其光谱测量的各种因素进行了较为详细的研究,确定了试验的最佳测定条件。该法准确、快速、简便。应用于内墙和木器涂料中有毒重金属元素的测定,结果满意。     

材质元素对不锈钢杯重金属析出量的影响

采用火花直读光谱仪分析了110批次不锈钢杯中C、S、Si、Mn、P、Cr、Ni7种材质元素的含量,同时采用石墨炉原子吸收分光光度法分析了它们的Pb、Cr、Ni、Cd、As5种重金属元素的析出量.研究了不锈钢材质对重金属元素析出量的影响.结果表明,材质元素Ni含量对重金属元素Pb的析出量有显著影响,材质元素C、Si、Mn、P含量对重金属元素Cr的析出量有显著影响,材质元素C、S、Mn、Cr、Ni含量对重金属元素Ni的析出量有显著影响,材质元素Si、Mn、P、Cr、Ni含量对重金属元素As的析出量有显著影响.     

食品中重金属测定方法研究

本文主要采用了高分辨连续光源石墨炉原子吸收光谱法对日常生活中常见的几种食物进行了重金属含量研究,并着重从试验方法、样品消解、定量分析等方面展开了论述。试验结果为目前失误重金属检测的定量分析法发展制订了相关的试验一句,并推动了我国食品质量安全管理工作的发展。     

渣料中锗的测定方法的改进

锗是一种非金属元素,性质介于硅和锡之间,但它的化学性质类似于临近族的元素,尤其是砷和锑。锗是一种重要的半导体材料,用于制造晶体管及各种电子装置。主要的终端应用为光纤系统与红外线光学（infraredoptics）,也用于聚合反应的催化剂,电子用途与太阳能电力等,是支撑高新技术发展的重要原料i。现在,开采锗用的主要矿石是闪锌矿（锌的主要矿石）,主要从其伴生矿和二次资源中回收ii,对我国某铅锌矿山富含锗硫化锌精矿采用高酸氧压浸出工艺处理．血,然后中和置换得到镓锗渣。化学上或毒物学上重要的锗化合物很少。锗的二氧化物,一种微溶于水的白色粉末,形成锗酸,这类似于硅酸。四氯化锗是一种不稳定的液体,四氟化锗是一种气体,它们很容易在水中水解。锗的测定方法根据含量不同,有滴定法iv,分光光度法vvi,荧光光谱法vii,原子发射光谱法viiiix。分光光度法是通过测定被测物质在特定波长处或一定波长范围内光的吸光度或发光强度,对该物质进行定性和定量分析的方法;电感耦合等离子体（ICP）是目前用于原子发射光谱的主要光源。ICP具有环形结构‘温度高‘电子密度高’惰性气氛等特点．本文对比分光光度法测矿石中锗和电感耦合等离子体原子发射光谱法（ICP—AES）测矿石中锗。得出分光光度干扰因素多而电感耦合等离子体原子发射光谱法（ICP-AES）具有检出限低,线性范围宽,精密度好,干扰小等特点。     

ICP-AES在检测日用陶瓷器皿中多种金属元素溶出量中的应用

本文根据电感耦合等离子体原子发射光谱仪(ICP-AES)分析速度快、分析灵敏度、准确度和精密度较高、检出限低的优点,在目前常用的分光光度计、原子吸收光谱仪等仪器之外,建立了一种准确、快速、简便的同时测定日用陶瓷器皿中汞、锰等多种金属元素溶出量的测定方法。日用陶瓷器皿经过4%乙酸溶液的萃取,萃取液采用电感耦合等离子体原子发射光谱(ICP-AES)进行分析,经过大量试验确定了最佳工作条件。采用本方法检测了1000个左右的日用陶瓷产品,及时、准确地提供了金属元素溶出量的数据,结果满意。     

电感耦合等离子体原子发射光谱法测定纯钛中加入的合金元素

采用电感耦合等离子体原子发射光谱法测定纯钛中加入的合金元素,确定了样品中元素的分析谱线以及优化了仪器工作条件。测试方法的加标回收率在98.0%～112.0%之间,RSD2.90%,与标准样品测试结果一致,测试方法高效可行。     

ICP-AES分析纯铝中硅含量的不确定度评定

讨论了采用电感耦合等离子体发射光谱法测定纯铝中硅量分析结果不确定度产生的原因。建立了数学模型,对测量重复性、标准溶液、标准曲线变动、试液体积及样品称量等引起的不确定分量进行评定,计算了合成标准不确定度和扩展不确定度,并给出纯铝中硅含量的不确定度报告。     

Microstructural effects on the short crack behaviour of a stainless steel weld metal during low-cycle fatigue

An experimental study into microstructural effects on short fatigue crack behaviour of 19 stainless steel weld metal smooth specimens during low-cycle fatigue is performed by a so-called ‘effective short fatigue crack criterion’. This material has a mixed microstructure in which it is difficult to distinguish the grains and measure the grain diameter. The columnar grain structure is made up of matrix-rich δ ferrite bands, and the distance between the neighbouring rich δ ferrite bands is an appropriate measurement for characterizing this structure. Particularly, the effective short fatigue cracks (ESFCs) always initiate from the bands of δ ferrite in the matrix in the weakest zone on one of the specimen surface zones which is orientated in accordance with the inner or outer surface of welded pipe from which the specimens were machined. These cracks exhibit characteristics of the microstructural short crack (MSC) and the physically small crack (PSC) stages. The average length of the ESFCs at the transition between MSC and PSC behaviour is ≈40 μm, while the corresponding fatigue life fraction is ≈0.3 at this transition. Different from previous test observations, the growth rate of the dominant effective short fatigue crack in the MSC stage still shows a decrease with fatigue cycling under the present low-cycle fatigue loading levels. A statistical evolution analysis of the growth rates reveals that the short fatigue crack growth is a damage process that gradually evolves from a non-ordered (chaotic) to a perfectly independent stochastic process, and then to an ordered (history-dependent) stochastic state. Correspondingly, the microstructural effects gradually evolve from a weak effect to a strong one in the MSC stage, which maximizes at the transition point. In the PSC stage, the effects gradually evolve from a strong to weak state. This improves our understanding that the short crack behaviour in the PSC stage is mainly related to the loading levels rather than microstructural effects.     

不锈钢真空钎焊

简述了不锈钢真空钎焊技术的应用、原理、工艺及设备情况,并概述了不锈钢真空钎焊技术的发展趋势.     

Ferritic stainless steel — A coinage material

General economic and metallurgical requirements, and processing methods for coinage materials are reviewed. The Indian effort at the development of ferritic stainless steels for coinage is discussed. The results of several trials at the Salem Steel Plant towards establishing the appropriate composition and processing route are presented and evaluated.     

Carbon deposition on stainless steel in oxidising environments

Abstract

The formation of low-density carbon deposits onto metallic heat transfer surfaces in industrial environments of high carbon activity can have a deleterious effect on thermal efficiency. Often this deposition occurs under reducing conditions and involves carbide (typically of iron) formation as part of the process. It is possible, however, for filamentous carbon deposits to form at much higher oxygen potentials where carbide formation is not favoured thermodynamically. This study considers one such situation by examining the behaviour of a 20Cr25Ni austenitic steel used as fuel cladding in Advanced Gas-cooled nuclear reactors (AGRs). Carbon deposition has been produced in laboratory by exposure at 550°C to CO₂ containing 1%CO and 1000 vppm C₂H₄; the dissociation of the latter additive generates carbon activities much greater than unity. The oxygen potential of this gas is sufficient to oxidise iron and chromium, of the major alloy constituents, but not nickel. The deposition takes place onto substrates that are prepared as electron microscope samples which are subsequently examined by SEM and HREM (high resolution electron microscopy) techniques. The deposits formed consist of solid carbon filaments, approximately 30 nm in diameter, with turbostratic atomic layering. Each filament contains a 10–20 nm metallic nickel particle near its tip. It is argued, and supported by HREM evidence, that such particles are produced as a direct result of the oxidation of the alloy and that prior oxidation is necessary to produce the observed carbon deposition. It is also shown that inhibition of carbon deposition occurs when the oxygen potential of the depositing gas is increased sufficiently to oxidise nickel.     

双电极奥氏体不锈钢焊条单弧焊工艺研究

本文研究了双电极奥氏体不锈钢焊条单弧焊电弧的静特性、焊接电流、电弧电压、焊芯间隙对双电极焊条单弧焊的工艺性能和焊缝成形的影响;通过热电偶测试技术,对双电极焊条单弧焊焊接过程中不同部位焊芯表面温升进行了测定.研究结果表明焊芯直径为φ4.0mm的双电极A102焊条,其合适焊接工艺参数为:焊接电流140～160A,电弧电压45V左右,焊条两芯间隙1.2～1.5mm,焊接板厚8mm的1Cr18Ni9Ti材料,焊缝成形良好.     

Corrosion of a stainless steel handrail

AISI 304 and 304L stainless steels are “workhores” grades of austenitic stainless steel frequently used in architectural applications, as well as in cookware, appliances, and numerous other applications where resistance to corrosion is required. This paper examines a corrosion failure (the appearance of rustlike stains on the surface) of a 304 stainless steel handrail that appears to have occurred as a result of contamination during the fabrication process.     

Laser metal deposition of multi-track walls of 308LSi stainless steel

Laser metal deposition using wire feeding system is increasingly becoming known as a process for making engineering components from the scratch. The process quality determines the end properties of the components hence, their lifetime performances in the service environments. In this study, single tracks and multiple tracks (walls) of AISI 308LSi on AISI 304 substrate were laser deposited using lateral wire feeding system. The microstructures of the deposited tracks were examined using optical microscopy and scanning electron microscopy. The macrohardness at different stages of the built walls was determined using Vickers hardness tester, while the ultimate tensile strength of the walls was investigated according to ASTM E8M-13 standard. The microstructure of the walls revealed nearly vertical columnar dendrites growing perpendicularly to the horizontal. The macrohardness of the deposited walls is within 167–194?HV but decreased from the bottom layer to the top layer. The tensile strength of the walls which ranges between 474 and 525?MPa depends on the wall building directions.     

酸性盐溶液中复合缓蚀剂对304不锈钢缓蚀作用的研究

为了研究不同缓蚀剂及复合型缓蚀剂对304不锈钢在酸性(pH=1)3.5%氯化钠溶液中的最佳缓蚀效果、最佳复配效果和最佳复配比例,采用失重法、电化学方法、表面形貌观察法、表面接触角和表面张力等表征方法对咪唑、硫脲、铬酸钾这三种物质的缓蚀效果及复配效果进行了研究.结果表明:失重法和表面形貌观察法均显示出三种物质都有一定的缓蚀效果,其缓蚀效率的大小关系为:硫脲铬酸钾咪唑,最佳缓蚀时间为24 h;通过极化曲线Tafel外推法、电化学阻抗谱法和表面形貌观察法等均可得出最佳复配效果为硫脲与铬酸钾复配;将100 ppm的硫脲5 mL和100 ppm的铬酸钾5 mL进行复配时(复配比为1∶1)通过表面接触角和表面张力的方法可得最小接触角为46.5°,最小表面张力71.9 mN/m,故最佳复配比为1∶1,即在硫脲与铬酸钾配比为1∶1且时间为24 h时,这种复合型缓蚀剂对304不锈钢的缓蚀效果最佳.     

316L不锈钢粉末注射成形件的烧结致密化行为

为了控制粉末注射成形零件的最终尺寸精度和力学性能,对316L不锈钢粉末注射成形件的烧结致密化行为进行了试验研究,分析了烧结温度和升温速率对试件致密化行为以及烧结件力学性能的影响.试验结果表明,致密化过程始于1080℃左右,主要在1200～1300℃的升温过程中快速进行,致密化速率随着升温速率的升高而升高.烧结件的抗拉强度、抗弯强度以及延伸率,不但取决于致密化程度,而且与微观结构有关.分析表明,将基于扩散控制和强度控制的烧结理论结合,可以有效地解释316L不锈钢粉末的致密化行为,需在现有的烧结模型中考虑强度影响因素,才能更真实地模拟烧结过程.     

Effect of welding processes on fatigue crack growth behaviour of AISI 409M ferritic stainless steel joints fabricated using duplex stainless steel fillers

The present investigation aims to study the effect of welding processes such as shielded metal arc welding (SMAW), gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW) on fatigue crack growth behaviour of the ferritic stainless steel (FSS) conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material and AISI 2209 grade duplex stainless steel (DSS) was used as filler metal, for preparing single pass butt welded joints. Centre cracked tensile (CCT) specimens were used to evaluate the fatigue crack growth behaviour. From this investigation, it is found that the GTAW joints showed superior fatigue crack growth resistance compared with SMAW and GMAW joints. The reasons for the superior performance were discussed in detail.