Experimental determination of interfacial toughness curves using Brazil-nut-sandwiches

A Brazil-nut-sandwich with a crack on a substrate/interlayer interface is developed for fracture testing. The fracture loading phase is controlled by the angle of diametral compression. Interfacial fracture mechanics is summarized and adopted in reporting data. Experiments are conducted with aluminum, brass, steel and plexiglass as substrates and epoxy as interlayer. Interfacial toughness curves are measured for large range of loading phase. Effects of the roughness of the surfaces prior to bonding on the interfacial toughness are demonstrated. Failure patterns for the adhesive structure under different loading modes are observed with a scanning electron microscope. For the metal/epoxy systems, when the remote loading is predominantly mode I, cracks tend to kink out of interfaces and run within the epoxy layer, although the bulk epoxy fracture energy is much higher than the interfacial toughness. At large loading phases, abnormally high apparent toughness is measured. These observations are discussed in the light of crack path selection criteria in adhesive joints and large scale contact zone of crack faces.     

Coarsening kinetics of silica in copper

Coarsening experiments have been conducted in the copper-silica system to study the aging behavior of compound precipitates in metallic systems under various conditions of temperature and atmosphere. Most of the experiments were conducted in a two-zone heating furnace, wherein a copper-cuprous oxide mixture was heated in one zone and the copper-silica sample was heated in the other zone, all enclosed in a quartz capsule. The temperature of the former zone determined the oxygen partial pressure in the system and the temperature of the latter zone determined the coarsening temperature. The silica particles from the coarsened samples were extraction-replicated and photographed in an electron microscope. The average radii obtained from these photographs were used to determine coarsening rate constants and activation energies. Isothermal coarsening kinetics followed the γ^-3 vs t law, indicating volume diffusion control. Activation energies were obtained for four different sets of experimental conditions. In each case the activation plot was linear. For coarsening under variable oxygen pressure the experimental activation energy of 530 kJ (127 Kcal) agrees fairly well with the predicted value of 514 kJ (123 Kcal) which takes into consideration the heats of solution and dissolution, as well as the activation energy for diffusion. For coarsening under constant oxygen pressures the experimental activation energies do not compare well with the predicted values, calculated on the basis of complete equilibration of oxygen between the gaseous phase and the sample. However, the experimental activation energies of 524 kJ (125 Kcal) and 447 kJ (107 Kcal) lie in the predicted range calculated on the basis of fixed amounts of oxygen in solution in copper. In no case is the activation energy for coarsening equal to that for diffusion of either species in the matrix as is sometimes assumed. Formerly DSR Staff Member.     

Coarsening kinetics of silica in copper

Coarsening experiments have been conducted in the copper-silica system to study the aging behavior of compound precipitates in metallic systems under various conditions of temperature and atmosphere. Most of the experiments were conducted in a two-zone heating furnace, wherein a copper-cuprous oxide mixture was heated in one zone and the copper-silica sample was heated in the other zone, all enclosed in a quartz capsule. The temperature of the former zone determined the oxygen partial pressure in the system and the temperature of the latter zone determined the coarsening temperature. The silica particles from the coarsened samples were extraction-replicated and photographed in an electron microscope. The average radii obtained from these photographs were used to determine coarsening rate constants and activation energies. Isothermal coarsening kinetics followed the γ^-3 vs t law, indicating volume diffusion control. Activation energies were obtained for four different sets of experimental conditions. In each case the activation plot was linear. For coarsening under variable oxygen pressure the experimental activation energy of 530 kJ (127 Kcal) agrees fairly well with the predicted value of 514 kJ (123 Kcal) which takes into consideration the heats of solution and dissolution, as well as the activation energy for diffusion. For coarsening under constant oxygen pressures the experimental activation energies do not compare well with the predicted values, calculated on the basis of complete equilibration of oxygen between the gaseous phase and the sample. However, the experimental activation energies of 524 kJ (125 Kcal) and 447 kJ (107 Kcal) lie in the predicted range calculated on the basis of fixed amounts of oxygen in solution in copper. In no case is the activation energy for coarsening equal to that for diffusion of either species in the matrix as is sometimes assumed.     

Experimental determination of solid-liquid interfacial energy for Zn solid solution in equilibrium with the Zn-Al eutectic liquid

The equilbrated grain boundary groove shapes for the Zn solid solution in equilibrium with the Zn-Al eutectic liquid were observed by rapid quenching. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient and the solid-liquid interfacial energy for the Zn solid solution in equilibrium with the Zn-Al eutectic liquid have been determined to be (5.80±0.18) × 10⁻⁸ Km and (93.496±7.57) × 10⁻³ Jm⁻² with the numerical method and from the Gibbs-Thomson equation, respectively. The grain boundary energy for the same material has been calculated to be (182.302±18.23)×10⁻³ Jm⁻² from the observed grain boundary groove shapes. The thermal conductivities of the solid and liquid phases for Zn-5 wt pct Al and Zn-0.5 wt pct Al alloys have also been measured.     

含铜原矿石中铜物相的快速分离与测定

经分相后的溶液不需用硝硫混酸处理,直接加入盐酸,调节酸度后即可用空气-乙炔原子吸收法测定,方法操作简便,测定速度快,结果满意.     

某铜冶炼渣选铜试验研究

某铜冶炼渣含铜1.13 %,工艺矿物学研究表明铜主要以类黄铜矿、类斑铜矿、类铜蓝以及金属铜的形式嵌布于该铜冶炼渣中。为高效回收其中的铜,进行了浮选试验研究。结果表明:在磨矿细度为≤0.045 mm占85 %的情况下,以酯-105作为捕收剂,硫化钠作为活化剂,采用二粗三精二扫的浮选工艺,获得了铜品位和回收率分别为18.10 %和87.46 %的铜精矿。      

分光光度法测定铜和铜合金中微量镍

近年来对于公害的控制要求甚严 ,国际环保纺织协会对于纺织品和玩具中Co ,Cr,Cd ,As,Sb ,Sn ,Pb和Ni等金属元素的含量提出了极为苛刻的要求 ,如要求纺织品中镍的含量必须小于4μg/g ,婴儿用的纺织品中镍的含量小于 1 μg/g。本公司制作拉链的铜合金原材料 ,要求测定铜中痕量镍。在GB/T - 5 1 2 1 .5 - 1 996《铜及铜合金化学分析方法 -镍量的测定》[1 ] 中采用电解分离 ,原子吸收分光光度法 ,测定范围 :0 0 0 1 0 %～1 5 0 % (质量分数 ) ,此标准测定范围已无法满足要求。为此 ,我们试验了铜与碘化钾反应 ,生成碘化亚铜沉淀分离后 ,…     

双波长分光光度法测定铜的研究

研究了 2-( 5-硝基-2- 吡啶偶氮 )-5 -二甲氨基苯胺 ( 5 NO2 PADMA)与铜的显色反应 ,建立了双波长分光光度法测定铜的新方法。结果表明 ,在pH 4.5HAc -NaAc缓冲溶液和乙醇存在下 ,Cu与 5 NO2 PADMA生成 1∶2的紫红色络合物 ,最大吸收正峰为 5 5 0nm ,负峰为 45 0nm ,正负峰吸光度绝对值之和与Cu浓度线性相关 ,Cu含量在 0～ 1.0mg/L内符合比尔定律 ,ε550 ,4 50 =6.74× 10 4 ,ε550 =3 .2 4     

Metal/semiconductor interfacial reactions

Vapor phase deposition of thin metal films on semiconductors followed by annealing frequently leads to the nucleation and growth of one or more reaction products in the vicinity of the metal/ semiconductor interface. Often, these products are intermetallic compounds that may be distributed as precipitates in the interfacial region. The composition, size, shape, and areal density of these precipitates may be the major factors in determining the electrical properties of the interface. The semiconductors studied were GaAs, SiC, and semiconducting diamond, while the metals were principally the refractory metals, although several other metals were also investigated. The interfaces of representative samples were examined using Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS), X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), including selected area electron diffraction (SAD), and optical metallography. The electrical properties were evaluated by current-potential (I-V) and Hall effect measurements. This paper is based on a presentation made in the “G. Marshall Pound Memorial Symposium on the Kinetics of Phase Transformations” presented as part of the 1990 fall meeting of TMS, October 8–12, 1990, in Detroit, MI, under the auspices of the ASM/MSD Phase Transformations Committee.     

碘量法测定铜阳极泥中铜的方法改进

使用行业标准方法 YS/T 745.1—2010碘量法测定铜阳极泥中铜时,采用氢溴酸除去试样中硒、砷、锑、锡等干扰元素,溶样过程操作繁琐,耗时长,易发生溅跳而造成无效结果,且检测效率低,因此不适用于冶炼企业大批量样品同时快速分析检测。试验使用盐酸分解试样,用硝硫混酸初步除硒等杂质、再用溴进一步除杂,替代氢溴酸除去试样中的杂质元素,从而对YS/T 745.1—2010碘量法测定铜阳极泥中铜的方法进行了改进。通过试验确定硝硫混酸用量为15mL,而后加入3mL盐酸溶解至溶液体积剩余约0.5mL时能完全溶解盐类。按照实验方法测定铜阳极泥试样中铜,测定结果的相对标准偏差(RSD,n=7)小于0.50%;各试样测定结果与行业标准方法 YS/T 745.1—2010结果一致,且两种方法间不存在显著性差异,可用于冶炼企业大批量快速分析检测铜阳极泥中铜量。     

邻氯苯基荧光酮光度法测定硅石中铝

荧光酮类试剂与铝的显色反应具有较高的灵敏度和较好选择性～［１,２］本文研究了邻氯苯基荧光酮（ＯＰＦ）与铝（ＩＩＩ）显色反应的条件及应用。在ｐＨ６．２和氯化十六烷基三甲基铵（ＣＴＭＡＣ）存在下,Ａ１（ＩＩＩ）与（ＱＰＦ）发生非常灵敏的显色反应,具有高的灵敏度和较好的选择性。最大吸收波长位于５７０ｎｍ,表观摩尔吸光系数ｓ＝１．３ｘ１０５。本法用于硅石、硅砖中三氧化二铝含量的测定。１实验部分１．１仪器和试剂７２１型分光光度计;ｐＨＳ—２型酸度计。三氧化二铝标准溶液：称取０．２６４６ｇ金属铝（９９．９９…     

某浮选铜精矿中铜、金浸出试验研究

在氯盐酸性体系中,对某浮选铜精矿进行了加压氧化浸铜的试验研究,探讨了温度、氧气分压、硫酸用量、氯化钠用量等对铜精矿中铜、铁浸出的影响。试验结果表明：在氧化温度110℃、氧分压0．45MPa、矿样粒度-0．043mm占85％、硫酸用量90g／L、氯化钠用量30g／L、液固比5／1、浸出时间2、5h、搅拌速度750r／min初始条件下,获得铜浸出率为92．18％。铜浸出渣经摇床重选脱硫,脱硫渣氰化浸金。当浮选精矿铜浸出率达到90％上时,对应渣中金的氰化浸出率都在96％以上。     

ICP-AES法同时分析有色金属铜及其合金中15种元素

采用全谱直读等离子体发射光谱仪,直接测定有色金属铜及其合金中Cr、Ni、Mn、P、Si、Al、Fe、Pb、Sn、As、Sb、Bi、Mg、Zr、Zn15种元素,优选了适宜的仪器测定参数和分析谱线,研究了基体效应、共存元素间干扰及干扰校正方法,通过对实际样品的分析试验,灵敏度、准确度、精密度、回收率均取得令人满意的结果.     

流动注射-分光光度法测定海水中微量铜

研究了以二苯碳酰二肼(DPC)为显色剂,NaCl溶液为反应介质,溴化十六烷基吡啶(CPB)、OP乳化剂为增敏剂测定Cu2+的分光光度体系,建立了流动注射分光光度测定海水中痕量Cu2+的新方法。对流动注射分析条件进行了优化,确定了检测波长为500 nm。在最优条件下,方法的检出限为0.003 mg/L,Cu2+的质量浓度在0.005~0.050 mg/L范围内,峰高测量值与浓度呈良好线性关系,线性方程为:H(mV)=0.616 1+0.175 2×10-3ρ(mg/L),相关系数r=0.998 8。对含量为0.020 mg/L的Cu2+标准溶液进行了11次平行测定,其相对标准偏差(RSD)为1.0%。经使用掩蔽剂可有效地消除其它共存元素的干扰,方法用于模拟海水、海水等高盐体系中Cu2+的测定,结果与石墨炉原子吸收分光光度法的结果相一致。     

地衣红褪色光度法测定痕量铜

在NH3.H2O-NH4Cl介质中,铜能灵敏地催化过氧化氢氧化地衣红褪色,利用这一原理,将非催化反应体系与催化反应体系在沸水中加热11.5 min,在波长582 nm处测定吸光度。非催化反应体系与催化反应体系吸光度比值的对数与痕量铜的质量浓度成正比,标准曲线方程为:lgA0/A=0.059 3+0.007 23ρCu2+(ng/10 mL),r=0.998 3,线性范围为0.5~80ng/mL,检出限1.24×10-10g/mL。该法可用于深井水、电镀废水及植物油中铜的测定。     

某含铜转炉渣回收铜浮选试验研究

某铜转炉渣中铜品位为2.78 %,铜元素主要以冰铜微珠的形式赋存于炉渣中,冰铜分布较为分散,嵌布粒度大小悬殊,不易单体解离.为了高效回收二次资源,针对该铜转炉渣的性质特点,进行了浮选试验研究.结果表明:在磨矿细度≤0.074 mm占80 %,酯-200作为捕收剂,粗选时间为9 min的条件下,采用“一粗-一精-一扫”浮选工艺,实验室闭路实验可获得铜品位和回收率分别为31.64 %和94.16 %的铜精矿.