喷气燃料中腐蚀性物质及其腐蚀性研究

分析了喷气燃料中导致银片腐蚀的两种物质活性硫和微生物，讨论了它们的来源.考察了硫化氢、元素硫、硫醇、硫醚、多硫化物等单独存在时对喷气燃料银片腐蚀的影响;同时研究了元素硫与其它硫化物以不同浓度混合时对喷气燃料银片腐蚀的影响.结果表明,硫化氢、元素硫是导致气燃料银片腐蚀不合格的主要原因.当与其它硫化物共存时,其它硫化物只起着协同的作用.     

臭氧气氛下LED灯光对银质文物模拟材料腐蚀变色的影响

目的研究臭氧与LED灯光共同作用于银质文物模拟材料的腐蚀行为和规律。方法采用石英晶体微天平(QCM)反应性监测及SEM-EDS等方法,研究了暴露于臭氧和LED灯下的银质文物模拟材料的腐蚀行为及其表面特征。结果暴露于LED灯或臭氧条件下的石英晶振片频率均有所下降,而暴露于LED灯加臭氧复合条件下的石英晶振片频率下降速率更快且最终下降值更多。此外,升高LED灯色温、增大臭氧浓度或提高环境温度,均会使石英晶振片频率下降速率更快且最终下降值更大。在臭氧质量浓度为5μg/L环境中,与无光照条件相比,LED光照下的银片表面的腐蚀产物及氧元素含量较多,并且LED灯的色温越高,其光照下的银片表面生成的腐蚀产物越多,但不同品牌的LED灯下的银片表面腐蚀产物生成量及氧元素含量均相近。结论臭氧与LED灯光均会加速银的腐蚀,两者共同作用时,会使银腐蚀更严重。升高LED灯色温、增加臭氧浓度或提升环境温度也同样会加速银的腐蚀,但不同品牌LED灯对银腐蚀的影响却相差无几。     

喷气燃料银片腐蚀抑制剂的研究

用X-射线光电子能谱仪(XPS)分析了腐蚀银片表面的腐蚀产物，结果表明：活性硫化物是造成喷气燃料银片腐蚀不合格的主要原因．考查了添加剂的抗腐蚀性能和热稳定性以及添加剂对喷气燃料热氧化安定性、磨擦学性能和水分离指数的影响．同时对添加剂的抗腐蚀作用机理进行了研究，DMTD衍生物添加剂在油相中可捕集活性硫，生成非腐蚀性硫化物，抑制银片腐蚀。     

喷气燃料银片腐蚀原因及快速检测技术比较

通过酸、碱、水、汞洗及硝酸银试验,以及卤素、氮化物分析和腐蚀产物分析,表明,喷气燃料对银片腐蚀的原因主要是微量的元素硫和多硫化合物.针对喷气燃料银片腐蚀试验时间过长的难题,研究比较了喷气燃料银片腐蚀电解池法、升温法和微波法的各自特点,提出了能够缩短化验时间、提高腐蚀速度的用微波加热促进银片腐蚀的快速检测方法.     

金属粉末腐蚀法对硫醇类硫化物腐蚀性的研究

选取正丁硫醇、异丁硫醇、正己硫醇和叔辛硫醇为模型硫化物，采用高压釜法研究了以上硫化物在200 ℃～350 ℃时对铜粉、铁粉的腐蚀性.研究发现，硫醇对两种金属粉末的腐蚀性与反应温度以及该硫醇自身的结构有关.温度越高，硫醇的腐蚀性越强；硫醇越容易分解，其腐蚀性也越强.      

Fe(OH)3的高温硫腐蚀产物氧化自燃性影响因素研究

 研究了Fe(OH)3在240℃～360℃高温条件下与元素硫的反应和硫化产物在95℃空气中的氧化反应，研究了硫化温度、硫化时间、氧化温度及水分对产物氧化自燃性的影响；同时采用X射线衍射仪鉴定硫化产物组成.结果表明，Fe(OH)3高温硫腐蚀产物主要是FeS2，该腐蚀产物在氧化温度95℃以上时具有较高氧化自燃性；硫化温度及氧化温度越高，硫化时间越长，有水存在时硫腐蚀产物的氧化自燃性越大，越容易氧化放热，引起油品自燃.     

喷气燃料银片腐蚀机理及快速试验方法探讨

喷气燃料中的微生物在适宜条件下生长并生活性硫化物,导致燃料具有腐蚀性。浸入这种燃料中的银片与活性硫化物相互作用,因发生电化学反应而被腐蚀。腐蚀反应速度与温度、Ｈ＾＋浓度等有关,改变试验条件,可使银片腐蚀试验时间缩短。     

还原性气氛中HCl和H2S导致Fe-Cr合金在700℃的加速失效

研究了Fe-8Cr,Fe-12Cr和Fe-18Cr合金在700℃含氯和两种硫含量还原性气氛中的腐蚀行为.气氛中H2S含量增加导致合金发生加速腐蚀,尤其造成Fe-18Cr合金表面氧化铬膜退化.合金的加速腐蚀与膜中生成的硫化物和氯化物密切相关.合金的腐蚀速率随其Cr含量的升高而降低.通过计算气氛中平衡时的氯势、氧势、硫势预测了合金与气氛可能发生的反应,并解释了腐蚀机制.     

环烷酸与有机硫对Cr5Mo钢高温腐蚀的交互作用研究

以环烷酸、十二硫醇及白油组成的合成油模拟含酸含硫原油,采用旋转高压釜动态失重实验和微观分析手段,研究280℃下不同硫含量和环烷酸对Cr5Mo低合金钢腐蚀行为的交互影响.研究表明,当油中硫醇(以硫计算)含量＜2 mass%时,硫化物含量上升会迅速增加环烷酸的腐蚀性;而当油中硫含量＞3 mass%后,由于保护性Fe7S8/...     

辉银矿在硫脲体系中浸出银的热力学分析

对辉银矿在硫脲体系中浸出银进行热力学分析,建立硫化银在酸性硫脲体系中的溶解腐蚀电化学机理模型－原电池反应模型。推导出其氧化溶解过程,主要分两步,第一步是硫化银在酸性铁离子的作用下溶解。第二步是分解后银离子的络合。计算了反应过程中形成原电池的电动势Ｅ、反应吉布斯自由能△Ｇ等。对浸出反应过程ＰＨ值对硫脲浸出体系的影响也进行了分析讨论,该研究为硫脲法从辉银矿中浸出银的实际生产工艺研究提供相应的理论基础。     

银币变色机理研究进展

银币的锈斑、变色问题是世界性难题,至今没有清晰的成因解释。本文综述了银币变色状况和变色的机理研究进展。重点评述了腐蚀介质对银变色的影响,包括氧、硫化氢、单质硫和二氧化硫的影响;简要介绍了环境湿度、温度、光照等环境因素对银变色的影响;对银币的大气腐蚀产物进行了分析,并展望了研究的发展方向。     

熔断器用银带变色初步分析

纯银熔体材料极易变色,采用扫描电镜(SEM)、X射线光电子能谱(XPS)和X射线衍射(XRD)等手段对银带变色状况和变色的机理进行了初步分析。结果表明,大气条件下退火会在银带表面形成一层白雾,其主要为Ag_2O;晶界处生成的一些不连续的黑色点状相,其主要成分为Ag、C和O;银带在大气条件长时间放置时,其表面将失去金属光泽,变成灰色,局部地区有黑斑散布,且斑点的分布离散,无明显的生长特点;银带加工过程中极易在其表面残留的C、Cu、Fe、Na、Mg等元素并非引起银币变色的主要因素;银带易与空气中的硫化氢、二氧化硫等发生反应,对银带产生腐蚀,致使银带变色,其腐蚀产物主要有Ag_2S、Ag_2SO_3、Ag_2O。     

电解萃取研究稀土元素对耐候钢中夹杂物的影响

为了研究稀土元素对钢中夹杂物的改性影响,以未添加稀土元素的Q235和添加了稀土元素的Q235RE两种耐候钢为研究对象,采用非水溶液电解萃取和物理磁选分离的方法提取出钢中的夹杂物,结合X射线衍射仪、扫描电镜和能谱仪分别对其类型、三维形貌进行研究。研究结果表明：未添加稀土元素的Q235钢中的夹杂物类型主要是硫化锰和铝、硅的复合氧化夹杂,且尺寸较大,呈现不规则多角状的镁铝氧化物、氧硫复合夹杂物尺寸可达40 μm,长条状硫化锰夹杂尺寸可达50 μm;稀土耐候钢Q235RE中夹杂物的类型主要是氧硫稀土复合夹杂物,夹杂物尺寸明显变小,长条状的硫化物被规则的球状的稀土硫化物及稀土氧硫复合夹杂物所取代,不规则多角状的氧化夹杂物尺寸小于15 μm,尺寸减小了约60%。     

Corrosion process of silver in environments containing 0.1 ppm H2S and 1.2 ppm NO2

The effects of sub‐ppm levels of nitrogen dioxide and hydrogen sulfide, and the adsorbed water on the corrosion of silver were studied in order to get a better understanding of the atmospheric corrosion process. An in situ mass balance was taken to monitor the kinetic behavior and the surface and the corrosion film were analyzed by X‐ray photoelectron spectroscopy (XPS). In H₂S environments, the tarnish film consisted of silver sulfide, and the corrosion rate depended upon oxygen as well as relative humidity. Silver was oxidized by only oxygen and the corrosion behavior conformed to a type of a parabolic law. In NO₂ environments, the corrosion film consisted of nitrate and oxide, and the corrosion rate depended upon oxygen as well as relative humidity. Compared to hydrogen sulfide, the formation of silver nitrate being strong hydroscopic reduced the effect of humidity on corrosion rate. In H₂S + NO₂ environment, the corrosion process was independent of both oxygen and humidity, and the kinetic behavior conformed to a linear law. The difference of corrosion process between H₂S or NO₂ environments and H₂S + NO₂ environments is thought to be due to the role of nitrogen dioxide as an ionic conductor and the presence of strong oxidizing species such as elemental sulfur which can be produced from the following reaction: H₂S + 2NO₂ → S + 2HNO₂. In addition, the role of adsorbed water affecting atmospheric corrosion process was mentioned based on the amount of adsorbed water from the three types of exposure environments.     

某含银高硫铜矿的综合回收试验

某含银高硫铜矿含铜0.76%、硫24.35%及银34.92 g/t，有价矿物种类多、矿石性质复杂，采用抑硫优先浮选铜-活化浮选硫的原则工艺流程进行试验，配合石灰作为硫化铁矿物抑制剂以及筛选出丁基黄药+酯-105作为硫化铜矿物的组合捕收剂，强化了银在铜精矿中的富集。在选定工艺条件下，可获得铜品位21.60%、银品位602.84 g/t的铜精矿(铜和银回收率分别为89.30%和54.39%)，硫品位45.60%、银21.55 g/t的硫精矿(硫和银回收率分别为89.79%和29.59%)，实现了铜、硫和银的综合回收利用。     

Sulfurierte Fettsäurederivate als Inhibitoren der Stahlkorrosion in Elementarschwefel,Schwefelwasserstoff und Chloride enthaltenden Systemen

Sulfurated fatty-acid derivatives as inhibitors of steel-corrosion in systems containing elementary sulfur, hydrogen sulfide and chloride It was shown experimentally in agents containing elementary sulfur, hydrogen sulfide, and chloride, that the corrosion of steel can be strongly prevented through the interaction of the following factors: (a) the presence of a polysulfidic organic compound with intramolecular sulfur-chains of at least three sulfur atoms, (b) the presence of an unsaturated organic coumpound, and (c) the presence of a nitrogen-containing compound. These nitrogen-compounds activated elementary sulfur (S₈) or long-chained polysulfides to nucleophilic and/or radical fragments by splitting the ring arrangement or the polysulfidic chain, respectively. The fragments seem to be able to react with multiple carbon bonds and metal-sulfur bonds and develop surface coating protective films.     

Silver sulfide leaching with a copper-thiosulfate solution in the absence of ammonia

Leaching from silver sulfide using a copper-thiosulfate solution in the absence of ammonia was investigated.It is found that silver sulfide could be effectively dissolved in the copper-thiosulfate system without ammonia.The effects of thiosulfate concentration,copper-to-thiosulfate ratio,agitation vigorousness,pH values,and dissolved gases on the leaching of silver sulfide with the copper-thiosulfate solution were studied.A maximum extraction of 95.1% was achieved with the 0.12 mol/L thiosulfate and the 0.048 mol/L copper sulfate.It is shown that copper-to-thiosulfate ratio is an important factor in silver sulfide dissolution and oxygen is not needed to leach silver sulfide,which leads to the instability of the leaching system at high copper-to-thiosulfate ratio.On the other hand,the silver extraction is not affected by the pulp pH values.     

Mechanism of the simultaneous formation of oxide and sulfide at the scale surface during the oxidation of a pure metal in mixed atmospheres

During the reaction of a pure metal with complex atmospheres containing both oxygen and sulfur, the formation of sulfide mixed with oxide is often observed at high temperature, contradicting thermodynamic predictions. The mechanism proposed so far to explain the formation of a duplex scale at the scale surface assumes a change in composition of the gas phase in a boundary layer next to the scale-gas interface and a reaction of the metal with the molecules of the two elements. This model is shown to be unable to explain the observed amounts of the less stable phase and the reaction rates when sulfur dioxide is the prevailing reacting species and is substituted by the assumption of a direct reaction with the SO₂ molecules. The thermodynamic equivalence of the two approaches is also pointed out.