TA15钛合金与铝合金和结构钢接触腐蚀与防护研究

通过测定TA15钛合金与铝合金和结构钢组成的电偶对的电偶电流的方法,研究了TA15钛合金在使用中与铝合金和结构钢接触时产生电偶腐蚀的敏感性.结果表明:TA15钛合金与铝合金和30CrMnSiA钢接触时会产生严重的电偶腐蚀,必须进行防护处理方可使用;与30CrMnSiNi2A钢接触产生的电偶腐蚀比较轻微.对铝合金和结构钢进行表面处理可以降低电偶腐蚀敏感性,表面处理后喷涂底漆可进一步降低电偶腐蚀敏感性.     

表面处理对TC21钛合金与铝合金和钢电偶腐蚀行为的影响

通过测定TC21钛合金与铝合金和钢电偶电流的方法,研究了TC21钛合金与铝合金和钢在使用接触时发生电偶腐蚀的敏感性.结果表明:TC21钛合金与铝合金和钢形成的电偶对极易发生电偶腐蚀,不能直接接触使用;对钛合金和铝合金分别进行阳极氧化处理可以在一定程度降低电偶腐蚀敏感性.TC21钛合金与钢形成的电偶对,电偶腐蚀行为与钢的成分有很大关系,对钛合金进行阳极氧化处理,对钢进行镀镉或镀镉-钛处理可以提高表面抗腐蚀性能,降低电偶腐蚀敏感性.当TC21钛合金与铝合金和钢接触使用时,必须采取有效的防护措施.     

TC4-DT钛合金与异种材料接触腐蚀与防护研究

通过测定TC4-DT钛合金与铝合金、钢及其阳极氧化或电镀后组成的电偶对的电偶电流的方法,研究了TC4-DT钛合金与上述异种材料之间发生电偶腐蚀的敏感性。结果表明:TC4-DT钛合金与铝合金、钢接触时极易发生电偶腐蚀,不能直接接触使用,必须采取有效的防护措施。对钛合金和铝合金进行阳极氧化处理,可降低电偶腐蚀敏感性;对钛合金进行阳极氧化处理,同时对钢进行电镀镉-钛处理可以在一定程度上降低电偶腐蚀敏感性。     

30CrMnSiNi2A钢与TC18钛合金表面处理前后的接触腐蚀性能

为了弄清30CrMnSiNi2A钢与TC18钛合金表面处理前后的接触腐蚀性能,对2种材料作了不同的表面处理,研究了其偶接电偶腐蚀的敏感性和表面防护效果;对低腐蚀敏感性的偶对不同的连接状态作了模拟海洋大气的盐雾加速腐蚀,测量了30CrMnSiNi2A钢的疲劳寿命,总结了优良的防护措施。结果表明：30CrMnSiNi2A钢与TC18钛合金直接接触腐蚀严重,电偶腐蚀敏感性为D级;30CrMnSiNi2A钢磷化与TC18钛合金阳极氧化后的偶对腐蚀敏感性降低至B级;30CrMnSiNi2A钢磷化涂漆后与TC18阳极氧化偶对的腐蚀敏感性仍为B级,但其电偶电流进一步降低,30CrMnSiNi2A钢（磷化后涂漆）与TC18（阳极化）之间无论是否胶结连接形成偶对时,盐雾腐蚀对30CrMnSiNi2A钢的疲劳寿命没有显著影响。30CrMnSiNi2A钢表面磷化后涂漆是防止接触腐蚀的有效措施。     

化学转化工艺对TC4钛合金表面性能及电偶腐蚀性能的影响

研究了不同化学转化工艺对钛合金表面膜形貌、膜成分、漆层结合力、与铝合金电偶腐蚀的影响。采用波音公司钛合金表面处理工艺(BAC5861)和中国航发北京航空材料研究院研制的RT5-1和RN5-1工艺在钛合金表面制备转化膜,用电偶腐蚀测试仪评价钛合金与铝合金的电偶腐蚀程度,交叉划格法评价漆层结合力。BAC5861处理的钛合金表面转化膜由Na3TiOF5组成。经BAC5861、RT5-1和RN5-1处理的钛合金表面与环氧树脂漆的结合力等级分别为9,10和6级,与未处理铝合金的电偶腐蚀敏感度分别为D,D,C级。结果表明,RT5-1和BAC5861工艺能明显提高钛合金基体与漆层的结合力,RN5-1工艺能有效降低钛合金与铝合金的电偶腐蚀敏感性,综合防电偶腐蚀和漆层结合力性能,RT5-1工艺优于RN5-1工艺和BAC5861工艺。     

钛合金与钢的电偶腐蚀行为研究

研究了TA28、Ti6321钛合金以及921A、907A船体结构钢在海水环境中的腐蚀特性及电化学行为,对两种钛合金与船体钢之间多面积比条件下的电偶腐蚀行为进行了试验。结果表明,当钛合金与钢直接接触时,钛合金与钢制船体间存在轻微的电偶腐蚀,采用电绝缘措施可以有效控制钛合金对钢制船体的电偶腐蚀。     

不同表面处理工艺对Ti-6A1-4V钛合金漆层结合力和电偶腐蚀性能影响

对比研究了经不同表面处理工艺(脉冲阳极氧化、直流阳极氧化、酸洗钝化)处理后的钛合金表面的漆层结合力及其与经铬酸阳极氧化处理的2024铝合金组成的电偶对的电偶腐蚀性能。结果表明:脉冲阳极氧化处理的钛合金表面呈明显的多孔结构,有效地提升了基体与漆层的结合力,同时钛合金表面的阳极氧化膜层还可有效降低与其对接的铝合金材料的电偶腐蚀倾向。在综合性能方面这种新型的脉冲阳极氧化工艺优于传统直流阳极氧化和酸洗钝化工艺。     

7050铝合金在海洋大气中的接触腐蚀防护研究

通过在海南开展的7050铝合金为期1年的户外大气暴露试验,并利用单侧容限因数法、概率统计T检验、形貌观察和EDX等手段研究了不同表面状态、连接状态的7050铝合金在海洋大气环境中的腐蚀特征和防护措施。研究表明:表面阳极化处理的7050铝合金的腐蚀是以点蚀萌生为主,特别是在与TC18钛合金连接处腐蚀比较集中;从T检验的结果得知,无论7050铝合金涂漆与否、装配与否,海洋大气腐蚀对疲劳寿命都有显著影响;涂漆和胶结装配可在一定程度上降低大气腐蚀和电偶腐蚀对7050铝合金的影响。     

人工海水中铝合金与复合材料T700电偶的腐蚀性能

采用失重法、腐蚀电化学试验方法、电偶腐蚀试验方法,研究了铝合金(Al6061)在人工海水中的耐腐蚀性能和电化学特性及其与环氧碳纤维复合材料T700偶接后的电偶腐蚀敏感性.结果表明,Al6061在人工海水中有一定的电化学腐蚀钝化性;Al6061与T700偶接后,电偶腐蚀使Al6061的腐蚀速度明显加快,人工海水中通入空气使电偶腐蚀程度增大;在T700表面涂敷环氧树脂涂层,能有效控制T700与Al6061之间的电偶腐蚀.     

钛合金紧固件的腐蚀及其防护技术

通过分析钛合金结构件的腐蚀性能及产生腐蚀的几种可能情形,详细探讨了钛合金紧固件腐蚀的原因.着重阐述了钛合金紧固件的腐蚀控制技术和控制思路,提出了钛合金紧固件缝隙腐蚀、电偶腐蚀、氢脆、钛合金紧固件之间及其与偶对金属之间的腐蚀控制方法.对钛合金紧固件常用的防护处理方法进行了较为全面的介绍,并就各种防护处理技术的性能情况进行了对比.     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。     

Synthesis and luminescent properties of alkali-metal and ammonium fluorosulfatozirconates and fluorosulfatohafnates

We have synthesized a variety of alkali-metal and ammonium fluorosulfatometallates (titanates, zirconates, and hafnates). The alkali fluorosulfatozirconates and fluorosulfatohafnates have been shown to exhibit efficient roentgenoluminescence (RL) in the UV through visible spectral region, with a maximum at 390–440 nm. Their RL spectra depend significantly on their composition (cation, anion, and water content), coordination of KF and K₂SO₄, and relative amounts of fluorine and SO₄ groups. We have examined the effect of heat treatment on the RL of these compounds. The rubidium and cesium fluorosulfatozirconates Rb₃Zr₂F₉SO₄ · 2H₂O, Cs₂ZrF₂(SO₄)₂ · 2H₂O, Cs₈Zr₄F₂(SO₄)₁₁ · 16H₂O, and Cs₂ZrF₄SO₄ offer the most efficient RL.     

Heat and Mass Transfer and Modeling and Prediction of Environmental Catastrophes

Basic definitions and concepts of the physicomathematical theory of natural catastrophes are given. Possibilities of mathematical modeling of natural and technogenic catastrophes are discussed in the context of the theory of heat and mass transfer and the mechanics of reacting media. The importance of taking into account conjugate heat and mass exchange in modeling catastrophes is emphasized. A formula for evaluating the probability of a collisional catastrophe is given.     

Multi-ferroic and magnetoelectric materials and interfaces

The existence of multiple ferroic orders in the same material and the coupling between them have been known for decades. However, these phenomena have mostly remained the theoretical domain owing to the fact that in single-phase materials such couplings are rare and weak. This situation has changed dramatically recently for at least two reasons: first, advances in materials fabrication have made it possible to manufacture these materials in structures of lower dimensionality, such as thin films or wires, or in compound structures such as laminates and epitaxial-layered heterostructures. In these designed materials, new degrees of freedom are accessible in which the coupling between ferroic orders can be greatly enhanced. Second, the miniaturization trend in conventional electronics is approaching the limits beyond which the reduction of the electronic element is becoming more and more difficult. One way to continue the current trends in computer power and storage increase, without further size reduction, is to use multi-functional materials that would enable new device capabilities. Here, we review the field of multi-ferroic (MF) and magnetoelectric (ME) materials, putting the emphasis on electronic effects at ME interfaces and MF tunnel junctions.     

CellML and associated tools and techniques

We have, in the last few years, witnessed the development and availability of an ever increasing number of computer models that describe complex biological structures and processes. The multi-scale and multi-physics nature of these models makes their development particularly challenging, not only from a biological or biophysical viewpoint but also from a mathematical and computational perspective. In addition, the issue of sharing and reusing such models has proved to be particularly problematic, with the published models often lacking information that is required to accurately reproduce the published results. The International Union of Physiological Sciences Physiome Project was launched in 1997 with the aim of tackling the aforementioned issues by providing a framework for the modelling of the human body. As part of this initiative, the specifications of the CellML mark-up language were released in 2001. Now, more than 7 years later, the time has come to assess the situation, in particular with regard to the tools and techniques that are now available to the modelling community. Thus, after introducing CellML, we review and discuss existing editors, validators, online repository, code generators and simulation environments, as well as the CellML Application Program Interface. We also address possible future directions including the need for additional mark-up languages.     

热交换器的分类及优缺点分析

热交换器是将不同温度介质之间的热量通过热传导的形式,由高温介质传递给低温介质,使介质达到生产所需温度的工艺设备,也可作为一种节能设备使用.通过对不同热交换器的结构分析,总结不同热交换器的优缺点、适用环境,为生产工艺设计人员及设备制造单位在选择可降低能耗、提高效率的设备上提供参考.     

The shape and stability of wall-bound and wall-edge-bound drops and bubbles

The behavior of wall-bound drops and bubbles is fundamental to many natural and industrial processes. Key characteristics of such capillary systems include interface shape and stability for a variety of gravity levels and orientations. Significant solutions are in hand for axisymmetric pendent drops for a variety of uniform boundary conditions along the contact line with gravity acting normal to a planar wall. The special case of a wall-bound drop or bubble that is also pinned at an edge (i.e. a ‘wall-edge-bound’ drop) is considered here where numerical solutions are obtained for interface shape and stability as functions of drop volume, contact angle, fluid properties, and uniform gravity vector. For a semi-infinite zero-thickness planar wall (plate), a critical contact angle is identified below which wall-edge-bound drops are always stable. The critical contact angle is computed as a function of the gravity vector. The numerical procedure, which makes no account for contact angle hysteresis, predicts that such wall-edge-bound drops are unconditionally unstable for any gravity field with a component that is tangent to the wall while inwardly normal to the edge. Select experiments are conducted that support the conclusions drawn from the numerical results.