ZrCr2 Laves相金属间化合物缺陷结构及缺陷软化效应

研究了ZrCr2 Laves相金属间化合物的点缺陷结构及其力学性质.结果表明:当ZrCr2 Laves相成分偏离化学计量比时,ZrCr2中存在着反位置(组分)缺陷.与其他结构的金属间化合物不同,ZrCr2的显微硬度值在化学计量比处取得最大值,而断裂韧性则在化学计量比处最小,点缺陷的存在对ZrCr2起着软化作用,并随着成分偏离化学计量比,ZrCr2的脆性度逐渐降低.对ZrCr2 Laves相金属化合物中的缺陷结构与其力学性能之间的关系进行了初步讨论.     

在大气-氨混合气氛中Pt、Pd和Ni的腐蚀

研究了在大气+氨混合气体(氨浓度11.8％)、压力0.1 MPa和温度为820～850℃环境中Pt、Pd和Ni金属的腐蚀,采用SEM、TEM和XPS观测和分析了试样腐蚀形貌特征和表面化学状态.所研究的3种金属显示了完全不同的腐蚀行为.讨论了Pt和Pd金属的腐蚀机制,腐蚀特性与金属及其氧化物的挥发、再沉积、氧吸附和晶面稳...     

腐蚀与防腐科学技术史话(2)

三、腐蚀理论的发展金属腐蚀有电化学腐蚀和化学腐蚀之分.原先金属氧化被认为是一种化学腐蚀.今天金属氧化有着电化学的性质.金属的腐蚀主要的是电化学腐蚀,因此使得电化学腐蚀理论的内容远比金属氧化理论丰富.     

金属催化化学沉积反应的电化学本质研究

以次磷酸盐酸性化学沉积镍体系为对象,研究了基体对化学沉积反应具有催化活性的电化学本质。首先利用稳定电位的测量明确化学沉积镍反应中次磷酸盐氧化的决定性作用,并发现次磷酸盐的氧化反应也具有特征反应电位。基于先前研究得到的次磷酸盐阳极氧化机制,提出对化学沉积镍反应具有催化活性的金属需符合的条件是,在化学镀液中金属的电位高于次磷酸盐的氧化还原电位的同时,必须低于该金属在此特定镀液中的零电荷电位值。并选取5种具有代表性的金属进行了实验验证     

脱除重油中有害金属杂质新技术

用化学药剂在一定条件下进行反应后用水萃取，并用 电脱水的方法脱除金属.研究了注药剂量、反应温度和反应时间等因素对脱除率的影响.     

金属玻璃中的非晶多形态转变

由于独特的无方向性金属键"无序"密堆而成的原子结构,金属玻璃能够兼具传统玻璃和晶态金属2者的特性,拥有一系列优异的物理、化学和机械性能,被认为具有广阔的应用前景;同时金属玻璃也是研究非平衡无序体系基础科学问题的一个特殊模型,因此获得了广泛的关注.材料相变的研究对于深入理解其原子结构,并实现结构和性能的调控有重要意义.根...     

影响空心玻璃微珠化学镀镍均匀性的因素

对外形规整的玻璃微珠进行化学镀镍,通过扫描电子显微镜观察,研究了影响粉末化学镀镍层形貌和均匀性的因素.结果表明:适量的稳定剂和较低的镀覆温度有利于形成致密的镀层,并能减少粉末中游离金属的量;pH值过低使镀层的致密度下降,过高导致镀液不稳定,产生游离金属.气体搅拌和机械搅拌可明显改善镀层均匀性,气体搅拌的效果优于机械搅拌.     

化学热处理在工业中的应用

化学热处理是表面处理中最有实用前途的方法。在用金属或盐熔融物以及气体介质来实现化学热处理的同时,近年来在国内外已出现了使用粉末材料饱和介质的稳定趋势。俄罗斯工学院研究出用金属热还原法可以直接得到饱和粉末介质。这样,一方面极大地增加了使用粉末介质化学热处理的可能性,另一方面也大大地减少了费用。化学热处理工艺在金属热还原方面的应     

乙酰丙酮铂族金属有机配合物的合成现状及用途

结合昆明贵金属研究所化学与药物研究室中进行的乙酰丙酮铂族金属有机配合物的合成工作,简要介绍了乙酰丙酮铂族金属有机配合物合成现状,并概述了乙酰丙酮铂族金属有机配合物的用途.     

物理气相沉积制备金属玻璃薄膜及其力学性能的样品尺寸效应

金属玻璃薄膜是在金属玻璃的基础上发展出来的一种新型薄膜材料,一方面继承无序原子排列结构所赋予的优异物理、化学和机械性能,另一方面有可能通过调整物理气相沉积工艺,构筑界面,制备纳米结构金属玻璃薄膜,克服块体金属玻璃的本征脆性.近年来,金属玻璃薄膜在各个领域快速发展,引起广泛的关注,已经成为新的研究热点.本文主要通过回顾最...     

金属光电化学阴极保护材料及其防腐功能化实现研究进展

与传统的腐蚀保护方法相比,光电化学阴极保护是一种节能、环保、经济的腐蚀防护技术.该技术的关键特征是,利用光电化学阴极保护材料在光照条件下产生光生电子,而光生电子以电势差作为驱动力转移到金属上,并富集在金属表面,导致金属的电位负移,从而实现对金属的强制保护.总结了近年来国内外光电化学阴极保护材料的制备方法与性能特点,针对目前TiO2薄膜材料存在的问题,阐述了通过形貌调控、元素掺杂、半导体复合、异质结构成、材料耦合等方式,提升光电化学阴极保护性能的策略和技术.概括了非TiO2类光电化学阴极保护纳米材料的性能及应用,主要有ZnO、SrTiO3、In2O3、g-C3N4、铋基金属氧化物等半导体材料.明确了近年来光电化学阴极保护材料防腐功能化实现的途径和方法,包括光阳极法和直接涂敷法,并比较了二者之间的优缺点.最后,提出了金属光电化学阴极保护材料及防腐功能化研究的发展趋势及存在的问题.     

A photoelectrochemical investigation of conversion coatings on Mg substrates

The structure, morphology and composition of conversion coatings grown in stannate bath on pure Mg were studied using potential–time, polarization curves, X-ray diffraction, scanning electron microscopy and photocurrent spectroscopy. The coating is manly constituted by crystalline magnesium–tin hydroxide, whose morphology and distribution depends on the conversion bath composition and temperature. The photoelectrochemical investigation allowed to estimate the band gap value of MgSn(OH)₆ and flat band potential. A sketch of the metal/passive film/electrolyte junction formed during conversion on the metal substrate is reported to account for the overall photoelectrochemical behaviour.     

Influence of surface treatment on the photoelectrochemical behaviour of Y-Ba-Cu-O thin films

Y-Ba-Cu-O films with different surface treatments have been studied by photoelectrochemical and XPS measurements. The influence of etching by bromine in ethanol of these films has been followed by means of the electrochemical oxidation of ferrocene in an aprotic electrolyte. From the dependence of dark and photocurrent on etching time it is concluded that Y-Ba-Cu-O thin films on LaAlO₃ are covered by a 1, 1nm thick nonstoichiometric surface layer. The cathodic polarization of Y-Ba-Cu-O at -0,9 V vs. Ag/AgCl in acetonitrile/0,1 M lithium perchlorate leads to the formation of a lithium-containing, oxygen-enriched surface layer. The photoelectrochemical response of the reduced films is similar to that of cuprous oxide and passive layers on copper.     

光电化学微区成象系统的建立

利用Dilor微区拉曼系统的现有设备建立了光电化学微区成象系统,并给出了钝化膜测量结果作为示例。     

Effect of ZnO on the corrosion of zinc,Q235 carbon steel and 304 stainless steel under white light illumination

This paper discusses the effects of the coupling of ZnO–Zn, Q235 carbon steel, and 304 stainless steel on their corrosion in 3.5% NaCl under white light illumination. In the presence of Na₂S, ZnO provided photoelectrochemical cathodic protection for the coupled metals. In the absence of Na₂S, ZnO could only provide photoelectrochemical cathodic protection for 304 stainless steel. Under white light illumination, the open circuit potential of ZnO photoelectrode shifted in the negative direction. ZnO provided photoelectrochemical cathodic protection to the metals only when the open circuit potential of ZnO photoelectrode was more negative than that of the metals.     

纳米TiO2-SnO2复合薄膜的光生阴极保护作用及机理研究

用溶胶-凝胶法和旋转涂膜技术在导电玻璃(ITO)表面构筑纳米TiO2膜和纳米TiO2-SnO2复合膜,应用AFM、XRD对膜的形貌及晶体结构进行表征.用光电化学和腐蚀电化学相结合技术,通过测试时间-电位曲线和交流阻抗谱研究光生阴极保护状态下316L不锈钢电极在0.5 mol/L NaCl溶液中的微观界面电荷分布及电子传递规律,探讨光生阴极保护的作用机理.结果表明以TiO2-SnO2复合膜作为光生阳极时,在紫外光照下,316L不锈钢电极可处在阴极保护状态,并且在切断光源后,光生电极电位仍可在较长的一段时间内维持在-0.2 V左右,仍具有一定的阴极保护作用.     

Scanning photoelectrochemical analysis of hydrogen permeation on ASTM A516 grade60 steel welded joints in a H2S containing solution

Hydrogen permeation through a welded joint of an ASTM A516 grade60 steel immersed in a H₂S solution was investigated using the scanning photoelectrochemical microscopy, an in situ technique providing images of the spatial distribution of hydrogen diffusion in real time and with good resolution. The paper presents images of hydrogen spatial distribution in the material including the base metal and heat-affected zone. Electrochemical impedance measurements were also performed in order to complement the information obtained.     

Preparation of CuS/BiVO_4 thin film and its efficacious photoelectrochemical performance in hydrogen generation

To drive photoelectrochemical water splitting on porous BiVO_4 photoanode, we herein prepared a carnationlike CuS powder by hydrothermal method and then loaded it onto BiVO_4 photoelectrode. Expectedly, the CuS/BiVO_4 composite not only presents a higher photocurrent response value at 1.23 V versus RHE(reversible hydrogen electrode) than pure BiVO_4 electrode under visible light irradiation, but also exhibits an excellent photoelectrochemical hydrogen production activity in comparison with either the BiVO_4 or the CuS. The high ameliorated performance of CuS/BiVO_4 composite may be due to the strong absorption of visible light and an effective abatement in combination of carriers. These results demonstrate an effective potential approach to design and construct efficient photoelectrochemical(PEC) systems.     

Inhibition behavior for copper corrosion by photoelectrochemical methods

wavelengthofmono chromatelightwas 4 2 0nm .3　RESULTSANDDISCUSSION3.1　ApplicationofphotoelectrochemicalmethodtoevaluatetheeffectsofinhibitorsforcoppercorrosionThestructuresoftheinhibitorsforcoppercorro sionshownintextareasfollows:Theinhibitioneffectsofdifferentinhibitorsforcoppercorrosioncanbeevaluatedby photoelec trochemicalmethod .AsshowninRef .[12 ],onanegativepotentialscan ,thepotentialcorrespondingtothecathodicphotocurrentJph=0isdefinedasΦV,atwhichCu2 Oontheelectrodesurfaceisc…     

Progress in organic photocatalysts

Organic materials have advantages of diversity,ease of functionality, self-assembly, etc. The varied mechanistic pathways also make it conceivable to design an appropriate photocatalyst for an identical reaction. From this perspective, organic photocatalysts find wide applications in homogeneous, heterogeneous photocatalysis and photoelectrochemical(PEC) solar cells. In this review, the form of the employed organic photocatalysts ranging from molecules, supported molecules, to nanostructures or thinfilm aggregates will be firstly discussed. Rational design strategies relating to each form are also provided, aiming to enhance the photoenergy conversion efficiency. Finally,the ongoing directions for future improvement of organic materials in high-quality optoelectronic devices are also proposed.