高温高压下Ni70Mn25Co5+Cu触媒对合成金刚石成核的影响

用六面顶金刚石压机研究了高温高压条件下，铜在Ni70Mn25Co5合金触媒中的扩散和形成含铜合金触媒的过程。同时，研究了这种不同含铜量的合金触媒在金刚石合成过程中对金刚石成核和生长的影响。研究发现在1670K、5．0GPa条件下，铜很容易进入Ni70Mn25Co5合金中形成NiMnCoCu合金触媒。这种含铜触媒对金刚石的成核有抑制作用，而且触媒随着铜含量的增加这种抑制作用越明显。在本研究的实验条件下，NiMnCo触媒中铜含量低于5％时，可以有效地使金刚石均匀成核并生长成大小均匀的金刚石。     

合成金刚石用水雾化触媒粉末Fe70Ni30性能的研究

我国近年普遍采用水雾化粉末触媒Fe70 Ni30合成金刚石,本文对这种粉末形貌、成分、粒度分布、氧含量、相组成等作了分析研究.结果表明:粉末呈不规则状;粒度呈正态分布,D50= 22.9 μm;粉末杂质含量很低:初始粉氧含量为0.2％(质量分数),将触媒粉和石墨粉混合(质量比3:7)压成合成柱,在1000℃,真空10-...     

原子发射光谱法测定锇中21个杂质元素

研究了用原子发射光谱法同时测定锇中21个杂质元素的分析方法。基于锇易与氧反应生成四氧化锇气体挥发的特性，采用加热挥发分离锇基体、碳粉捕集杂质元素、直流电弧激发摄谱和计算机控制测光仪进行自动测定。实验考查了样品处理、测定条件和方法准确度。在660℃下恒温1．5h可使锇基体挥发至＜0．1％，而杂质元素不损失。到定了3个杂质含量不同的校样，测定百分误差均≤25%。方法简便快速，测定结果令人满意。     

Ni70Mn25Co5触媒片的表面缺陷观测

本从观测常规产品Ni70Mn25Co5触媒合金片的表面缺陷入手，讨论了触媒片表观质量对金刚石合成效果的影响，从而也为触媒产品质量标准的制定提供了某些参考依据。     

Ni—Mn粉末触媒及金刚石合成的研究

对Ｎｉ－Ｍｎ粉末触媒的基本物理化学特征及其高温高压金刚石合成应用进行了初步研究,讨论了该粉末触媒中孔隙对触媒合成金刚石效果的影响。结果表明,Ｎｉ－Ｍｎ粉末触媒为单相固溶体合金,有较好的催溶性能。其熔点低,适用于合成细颗粒人造金刚石。     

铁基触媒中的初生渗碳体与金刚石单晶的合成

本文利用光学显微镜、扫描电镜和X射线衍射仪研究了金刚石合成后的铁基触媒组织结构。结果表明，组织中有较多的初生渗碳体时，金刚石的质量好，产量高；反之，则质量差，数量少。分析表明：触媒从高温液态到室温固态经历了初生渗碳体的析出、长大和共晶凝固两个过程，高温高压下金刚石的形核与长大是在触媒熔液经历初生渗碳体阶段时形成的。金刚石的生长极有可能是通过初生渗碳体的分解实现的，碳原子集团从渗碳体脱溶，然后堆积到金刚石上。本文从冶金反应过程证明了金刚石是由初生渗碳体转变而来的。     

电感耦合等离子体原子发射光谱法测定羰基镍粉中16种杂质元素量

建立电感耦合等离子体原子发射光谱法测定羰基镍粉中砷、镉、铅、锌、锑、铋、锡、钴、铜、锰、镁、铝、铁、钙、钼、硅等杂质元素含量的方法。采用硝酸（3+2）溶解样品,考察了酸度对测定的影响,确定了各元素最佳的分析谱线。在标准溶液中,元素含量分别为0、0.025、0.1、0.5、1.0μg/mL时,十六种元素的强度与浓度呈现良好的线性关系,对应的相关系数均大于0.999。最终的加标回收率为94.0%～104.0%,相对标准偏差RSD<6.53%(n=7)。该方法有效的提升了羰基镍粉中多元素分析的效率,满足硬质合金生产工艺的要求。     

金刚石合成中某些现象的分析与研究

采用ＳＥＭ和ＥＰＡ技术对ＮｉＦｅＭｎ触媒合金在金刚石合成中的一些现象作了研究并探讨了触媒合金在高压合成下的作用机理。研究表明，经高温高压合成后ＮｉＦｅＭｎ触媒片表面存在局部成份起伏，Ｆｅ原子在金属／石墨界面及金属／金刚石界面富集；这种成份（浓度）起伏对金刚石晶体的形核与生长都有一定影响。     

直流电弧光谱技术分析铌及铌基化合物中杂质元素

原子发射光谱中直流电弧光谱技术在众多粉末材料的检测中具有许多其它技术难以企及的优势,本试验采用全谱直流电弧直读光谱仪,无需样品分解,直接将铌及铌基化合物转化为氧化物,配制系列氧化铌光谱标样,运用载体分馏效应,用直流电弧阳极激发,电极中实现杂质元素与基体分馏,依据时序分析和扫描峰确定元素分析波长、元素积分时间、背景扣除点,建立Nb中Fe、Ti、Ta、Al、Mn、Ni、Cr、Zr、Hf、Co、Sb、Sn、V、Mg、Pb、Si、Mo、As、Bi等19种杂质元素同时测定的分析方法,加标回收率在95%～115%之间,RSD在8%～19%之间,分析结果同国标方法 GB/T 15076.10《钽铌化学分析方法铌中铁、镍、铬、钛、锆、铝和锰量的测定》、GB/T 15076.11《钽铌化学分析方法铌中砷、锑、铅、锡和铋量的测定》一致。     

钽中杂质元素分析的DCA全谱直读方法研究

原子发射光谱中直流电弧光谱技术在众多粉末材料的检测中具有许多其它技术难以企及的优势,本试验无需样品分解,直接将钽及其化合物转化为氧化物,配制系列氧化钽光谱标样,通过选择采用94%光谱纯碳粉同6%氟化钠混合做载体,15 A分析电流,运用载体分馏效应,用直流电弧阳极激发,电极中实现杂质元素与基体分馏,依据时序分析和扫描峰,确定元素分析波长、元素积分时间、背景扣除点,建立Ta中Fe、Al、Si、Mn、Mg、Ni、Ti、V、Co、Pb、Bi、Sn、Zr、Sb、Cu、Ca、Cr、Nb、Mo、Y、Ga、Ba、In、Ag、As、Re、Zn、Hf、Cd、Te等30种杂质元素同时测定的分析方法,测定范围0.3⁶00μg/g,加标回收率在93%600μg/g,加标回收率在93%¹15%之间,RSD在6%115%之间,RSD在6%²0%之间。     

Characteristics and formation of corrosion product films of 70Cu-30Ni alloy in seawater

The corrosion product films of 70Cu-30Ni alloy, composed of recrystallized grains or deformed and recrystallized grains, were investigated in 3.5% NaCl and natural seawater by electrochemical techniques, SEM, EDX and AES. The recrystallized alloy displayed a steady increase in the polarization resistance while the alloy of incomplete recrystallization kept its polarization resistance at a low level as increasing the immersion time in 3.5% NaCl. The films formed on the recrystallized alloy in seawater were thin, uniform and rich in nickel. After long-term immersion, the films, still thin and protective, consisted of convex lines and smooth zones between the lines. The convex lines were richer in nickel and contained more seawater species than the zones, so this led the lines to preferentially dissolve and new lines to appear where the film grew slower. Immersed in seawater, the alloy of incomplete recrystallization showed thick, loose and porous films, of which the inner layer was denickelified and the outer layer contained a great amount of seawater species, and of which the underlying substrate was found with severe intergranular corrosion. The tube specimens of incomplete recrystallization for four-year immersion were perforated by intergranular corrosion.     

Relationship of corrosion product films and recrystallization of 70Cu‐30Ni alloy

The corrosion and microstructure of 70Cu‐30Ni alloy plates and commercial tubes were investigated by processing, electrochemical technique and seawater exposure as well as optical microscopy, SEM, EDX and AES. The alloy plate with incomplete recrystallization, consisting of deformed and recrystallized grains, demonstrates loose and porous outer layers and denickelification in the inner layers for its corrosion product films, whereas the recrystallized alloy plate forms smooth and compact corrosion product films rich in nickel after immersion in seawater for 3 and 6 months. The incompletely recrystallized alloy tube keeps an active state and the recrystallized tube has a passive zone in the anodic polarization curve in 3.5% sodium chloride. Furthermore, the former shows loose and thick corrosion product films, which are of denickelification in the inner layer and contain a significant amount of seawater species in the outer layer, and on the surface of the latter are thin uniform and compact corrosion product films containing a Ni enrichment zone which becomes richer in Ni and wider with increasing immersion time. It is found that intergranular corrosion proceeds along the boundaries of deformed and recrystallized grains, and it is ascribed to electrochemical cells built for the reason of potential difference between the two kinds of grains.     

Banding formation and eutectic lamellar growth in directional solidified Ni50Al20Fe30 alloy

Banding formation and eutectic lamellar growth in a directionally solidified Ni₅₀Al₂₀Fe₃₀ alloy were investigated. It was found that the banding area consists of two layers. The first layer is a γ layer, while the subsequent one is a γ layer. The composition of various phases around the banding area changes with the solidification process. The banding is formed by two steps process and caused by factors such as the fractions during the sample growth process. It was found that the band was found at relatively low growth rate. Therefore. this study indicates that increasing the growth rate is an effective method to eliminate the band formation. Eutectic lamellae nucleate and grow again after the banding formation. During the initial transition lamellar growth, the relationship between the square lamellar spacing, γ₂, and the distance from, the banding, d, can be described by the following equation: γ₂ = K [1-exp(A.d)] where K and A are constant.     

Seawater corrosion of 70Cu‐30Ni alloy of incomplete recrystallization of intermittent and full immersion

The corrosion of 70Cu‐30Ni alloy of incomplete recrystallization was investigated by electrochemical technique, intermittent and full immersion in natural seawater, SEM and AES. Exposed to seawater for a short time, 70Cu‐30Ni alloy formed uniform and compact corrosion product films, which were rich in nickel, oxygen and seawater species for intermittent immersion; while the alloy fully immersed displayed loose and thick films, which were of denickelification and intergranular corrosion occurred to the underlying substrate. It was found that some regular crystals situated at the intersection of boundaries or the outer layer of the film and the crystals are ascribed to the reduction of cuprous ions to compensate the deficiency of oxygen for the cathodic process. Intergranular corrosion was observed in the underlying substrate for intermittent immersion after a long‐term exposure. Intermittent immersion can, to some degree, slow down the corrosion but not prevent the alloy of incomplete recrystallization from intergranular corrosion. Consequently, the corrosion mechanism of 70Cu‐30Ni alloy is proposed to be determined by its microstructure, independent of exposure conditions.     

Cu-30Ni合金机械冲击表面纳米化组织和性能(英文)

采用大应力塑性变形(机械冲击)技术对Cu-30Ni合金表面进行纳米化处理。利用原子力显微镜技术、纳米压痕试样、显微硬度测量、电化学分析和电子功函数等手段分别测试原始样品、大应力塑性变形纳米化处理样品的晶粒尺寸、力学性能、腐蚀性能。结果表明,与原始样品相比,大应力塑性变形纳米化处理样品的表面晶粒尺寸达到40nm;力学性能显著改善。电化学测试表明,表面纳米化提高了合金的耐腐蚀性能,耐腐蚀性能变化与电子功函数变化一致。机械冲击工艺技术能够使Cu-30Ni合金表面纳米化,从而提高了表面力学性能和耐腐蚀性能。     

Simultaneous determination of some trace metal impurities in high-purity sodium tungstate using coprecipitation and inductively coupled plasma atomic emission spectrometry

A method based on the combination of coprecipitation with inductively coupled plasma atomic emission spectrometry (ICP-AES) was developed for the determination of impurities in high-purity sodium tungstate. Six elements(Co,Cu,Fe,Mn,Ni,and Pb) were coprecipitated by lanthanum hydroxide so as to be concentrated and separated from the tungsten matrix. Effects of some factors on the recoveries of the analytes and on the residual amount of sodium tungstate were investigated, and the optimum conditions for the coprecipitation were proposed. Matrix-matching calibration curve method was used for the analysis. It is shown that the elements mentioned above can be quantitatively recovered. The detection limits for Co, Cu, Fe, Mn, Ni, and Pb are 0.07, 0.4, 0.2, 0.1, 0.6, and 1.3 μg.g^-1, respectively. The recoveries vary from 92.5% to 108%, and the relative standard deviations (RSDs) are in the range of 3.1%-5.5%.     

Nuclear microprobe methods for investigation of the corrosion of zircaloy-2 and an Fe44Ni17Cr alloy (PE-16)

Nuclear microprobe analysis has been established as a suitable technique for investigation of the oxidative corrosion of Zircaloy-2 and PE-16. The determination of oxygen spatial distributions by the reaction O(d, p)¹⁷O has been examined in detail. Suitable calibration procedures have been found for the measurement of oxygen in the concentration range 0.01–35%. A means of correcting for interference by surface oxide films has been introduced. The extent of interference by nitrogen and boron has been established. In the examination of PE-16, the reaction ¹²C(d, p)¹³C was used to measure carbon and deuteron-generated X-rays to measure Cr and Ti.     

Electrochemical frequency modulation and inductively coupled plasma atomic emission spectroscopy methods for monitoring corrosion rates and inhibition of low alloy steel corrosion in HCl solutions and a test for validity of the Tafel extrapolation method

The inhibition effect of glycine (Gly) towards the corrosion of low alloy steel ASTM A213 grade T22 boiler steel was studied in aerated stagnant 0.50 M HCl solutions in the temperature range 20-60 °C using potentiodynamic polarization (Tafel polarization and linear polarization) and impedance techniques, complemented with scanning electron microscope (SEM) and energy dispersive X-ray (EDX). Electrochemical frequency modulation (EFM), a non-destructive corrosion measurement technique that can directly give values of corrosion current without prior knowledge of Tafel constants, is also presented here. Experimental corrosion rates determined by the Tafel extrapolation method are compared with corrosion rates obtained by electrochemical, namely EFM technique, and chemical (i.e., non-electrochemical) method for steel in HCl. The chemical method of confirmation of the corrosion rates involved determination of the dissolved cation, using ICP-AES (inductively coupled plasma atomic emission spectrometry) method of analysis. Corrosion rates (in mm y⁻¹) obtained from the electrochemical (Tafel extrapolation and EFM) and the chemical method, ICP, are in a good agreement. Polarization studies have shown that Gly is a good “green”, mixed-type inhibitor with cathodic predominance. The inhibition process was attributed to the formation of an adsorbed film on the metal surface that protects the metal against corrosive agents. Scanning electron microscopy (SEM) and energy dispersion X-ray (EDX) examinations of the electrode surface confirmed the existence of such an adsorbed film. The inhibition efficiency increases with increase in Gly concentration, while it decreases with solution temperature. Temkin isotherm is successfully applied to describe the adsorption process. Thermodynamic functions for the adsorption process were determined.     

Microstructural analysis of thermally induced and deformation induced martensitic transformations in Fe–12.5 wt.% Mn–5.5 wt.% Si–9 wt.% Cr–3.5 wt.% Ni alloy

Martensitic transformations induced by thermally and compression deformation at room temperature in Fe–12.5 wt.% Mn–5.5 wt.% Si–9 wt.% Cr–3.5 wt.% Ni alloy were studied in detail by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). From microstructural observations, it was seen that heat treated samples exhibited regular overlapping of stacking faults and ɛ martensite plates were formed parallel to each other. Also, TEM investigations showed that the orientation relationship between γ (fcc) and ɛ (hcp) phases corresponds to Shoji–Nishiyama type. With applied low plastic deformation rate, only ɛ martensite occurred in austenite grain. As a consequence, 4 and 25% plastic deformation at room temperature caused ɛ martensite formation in austenite phase and the new ɛ (hcp) and α′ (bcc) martensite formation in martensite phases, respectively. Orientation relationship between ɛ and α′ phases was found by the electron diffraction analysis.