不同pH氯化钠溶液对P110S油套管钢腐蚀磨损交互作用的影响

采用失重法和电化学方法研究了P110S油套管钢在不同pH氯化钠溶液中的腐蚀磨损行为,分析了试样表面的磨损产物。结果表明:试验钢在pH为3的氯化钠溶液中的腐蚀磨损速率最大,而在pH为7氯化钠溶液中的最小,在不同pH氯化钠溶液中,试验钢的腐蚀与磨损呈正交互作用;腐蚀磨损后试样的自腐蚀电位在pH为11的氯化钠溶液中最低,在pH为3,7的氯化钠溶液中相差不大,溶液pH对腐蚀磨损前试样的自腐蚀电位影响不大;随着氯化钠溶液pH的增加,试样表面磨损变形程度增大,腐蚀产物中氧、铁原子比减小。     

中子吸收用B4C/6061Al复合材料在硼酸水溶液中的腐蚀行为

对B_4C/6061Al复合材料分别进行酸洗、阳极化和喷丸处理,研究了其在硼酸水溶液(90℃)中的均匀腐蚀、缝隙腐蚀和包覆腐蚀行为。结果表明:酸洗、阳极化、喷丸处理试样腐蚀不同时间后的质量、厚度、密度均变化不大;阳极化和喷丸处理试样均匀腐蚀后未呈现明显腐蚀现象,酸洗处理复合材料表面颜色随腐蚀时间延长而加深;缝隙腐蚀后,不同表面处理试样非模拟缝隙腐蚀区表面状态良好,而模拟缝隙腐蚀区的腐蚀程度较为严重;包覆腐蚀后,不同表面处理试样均发生局部腐蚀,生成了絮状的铝氧化物,阳极化处理试样的阳极化膜局部脱落。     

外加电势对304不锈钢在乙酸溶液中腐蚀磨损与重金属迁移行为的影响

探究不同外加电位条件下304不锈钢在体积分数为3%的乙酸溶液中的腐蚀磨损行为及重金属元素的迁移规律;对摩擦过程中不锈钢在3%的乙酸溶液中的电位进行极化扫描,根据得出的极化曲线在阴极和阳极区选定5个电位,考察在不同电位下304不锈钢摩擦因数及腐蚀电流随滑动时间的变化规律,并计算相应的磨损体积;通过磨痕形貌的观察,推测腐蚀磨损机制,并探讨腐蚀磨损过程中304不锈钢中重金属元素的迁移规律。实验结果表明:在阴极区,不锈钢仅受到纯机械磨损作用,随着表面的钝化膜不断去除,摩擦因数逐渐降低,磨损率相对较低;而在阳极区,不锈钢受到磨损与腐蚀的共同作用,摩擦因数逐渐升高,磨损量和极化电流不断增大,在外加电势达到1. 0 V时,不锈钢的磨损体积是OCP (-0.4 V)时的3倍,磨损机制转变为腐蚀磨损、磨粒磨损为主的混合作用机制;同时Cr和Ni 2种重金属元素的迁移量分别达到114、58μg/L。     

CO2和H2S对FV520B不锈钢在NaCl溶液中电化学腐蚀行为的影响

采用动电位极化和电化学阻抗谱研究了FV520B不锈钢在3.5%(质量分数,下同)NaCl溶液以及在分别通入CO_2、H_2S、CO_2+H_2S气体的3.5%NaCl溶液中的电化学腐蚀行为。结果表明:在3.5%NaCl溶液中通入CO_2或H_2S时,试验钢的开路电位负移,极化电阻减小,耐腐蚀性能变差;试验钢在4种腐蚀介质中的极化曲线均呈阳极溶解特征,在3.5%NaCl和通入CO_2的3.5%NaCl溶液中,腐蚀受阳极过程控制,在通入H_2S的3.5%NaCl溶液中,腐蚀受阴极过程控制,而在同时通入CO_2和H_2S的3.5%NaCl溶液中,腐蚀受阴极和阳极过程共同控制。     

TC4表面等离子沉积Al2 O3/MoS2涂层及性能分析

利用阴极等离子电解沉积技术在Ti6Al4V表面制备了Al_2O_3/MoS_2减磨耐蚀复合涂层。利用XRD、SEM、DES等检测手段分析了脉冲电压对复合涂层的形貌、物相组成及涂层摩擦学/腐蚀性能的影响。结果表明,随着电压的升高,涂层中α-Al_2O_3硬质相的质量分数增加,但涂层表面粗糙度和孔径增大,导致MoS2的质量分数先增加然后下降。在干滑擦磨损试验中,300 V以下的试样摩擦系数和磨损率最低,过高电压不利于耐磨性能的提高。腐蚀测试表明涂层样品比未处理的样品具有更好的耐腐蚀性。     

高强管线钢在高pH环境中的慢应变拉伸试验研究

通过对国产X80管线钢在高pH环境下慢应变速率拉伸试验（SSRT）研究，分析了国产X80管线钢在0．5mol／L Na2CO3＋1mol／L NaHCO3溶液中的应力腐蚀破裂（SCC）敏感性，并对其破裂断口进行SEM观察和分析。外加电位时，X80管线钢在高pH溶液中SSRT试验结果表明，随着外加电位的负向增大，X80管线钢的断裂时间tf,延伸率δ和断面收缩率RA明显降低，而裂纹扩展速率CGR增加，SCC敏感性增加。在阴极电位条件下断口呈准解理断裂，断口处有明显的应力腐蚀破裂发生，在自腐蚀电位和阳极电位条件下，X80钢试样断口主要是韧性断裂，SCC敏感性很低。     

腐蚀/疲劳交替作用下2A12-T4铝合金的损伤特性

对2A12-T4铝合金进行腐蚀/疲劳交替试验,探讨了其在腐蚀/疲劳交替作用下的损伤特性。结果表明:腐蚀和疲劳的耦合作用加剧了疲劳寿命的下降,腐蚀坑在垂直于疲劳加载方向上形成表面小裂纹;在腐蚀/疲劳交替作用下,试样断口表面会产生多个疲劳源;腐蚀/疲劳交替试验更接近飞机结构真实的使用坏境。     

磁场作用下45钢/45钢稳定摩擦的磨损机制

为研究不同强度磁场作用下45#钢自配副的磨损机制及磁场强度与磨损率的关系,在不同强度磁场作用下进行45钢自配副的销、盘干摩擦试验,分析销试样的磨损性能及其磨损面的形貌、化学成分。结果表明:随着磁场强度增加,销试样磨损率经历快速减小、缓慢减小和基本稳定3个连续变化阶段,使其由严重磨损转变为轻微磨损的临界磁场强度约为17. 4×10~3A/m;无磁场作用时,销试样磨损面存在犁沟,45钢/45钢的磨损类型为磨粒磨损;随着磁场强度的增加,销试样磨损面发生氧化并生成了Fe_2O_3,摩擦过程中氧化物剥落形成凹坑,45钢/45钢的磨损类型主要为氧化磨损;磁场增加使销试样磨损面更加光滑。可以得出:一定强度的磁场使45钢自配副摩擦过程由磨粒磨损转变为氧化磨损,而氧化磨损类型对应45钢自配副的轻微磨损。     

漏磁检测剩余磁场对油气管道直流杂散电流腐蚀行为的影响

为探究管体磁化产生的磁场对油气管道直流杂散电流腐蚀行为的影响,采用自行设计试验装置模拟管道真实漏磁场,以恒电位阳极极化、电化学阻抗谱、表面分析技术及失重法研究了库尔勒土壤模拟液中磁化及未磁化的L360管线钢试样在0.5 V恒定阳极极化电位下的极化腐蚀电流、腐蚀失重、腐蚀产物和腐蚀形貌的差异。试验结果表明,磁化管体的磁场使干扰电位强度为0.5 V的直流杂散电流腐蚀速率增加21%,但对腐蚀形貌影响不明显。磁场作用机理分析表明,磁场产生的洛伦兹力驱动反应界面附近腐蚀介质旋转运动,从而增大反应物的扩散速率,减小反应界面铁离子浓度及界面扩散层厚度,从而增大腐蚀速率;磁场梯度力作用下,腐蚀坑内聚集更高浓度的Fe²⁺使腐蚀受到一定程度抑制。磁场使管线钢直流杂散电流腐蚀速率大幅提升,应提高开展过漏磁内检测的油气管道直流杂散电流评价标准。     

不锈钢阳极氧化

一、工艺参数: 介质:20～30%硫酸 0.1%钼酸钠;电流密度:10～20毫安/厘米~2;处理时间:10～20分钟;处理温度:室温;阳极:不锈钢;阴极:铅板。二、处理效果: 1.阳极氧化处理后的不锈钢,其显著的特点是大大地提高了它的耐蚀性。例如1Cr18Ni9Ti钢在沸腾的5%硫酸中是不耐蚀的,腐蚀速率大于10毫米/年。我们将该钢种试样进行阳极氧化处理后,在同样的条件下经过805小时试验后仍未发生腐蚀,试样表面仍光亮如新。图1表示阳极氧化处理后的1Cr18Ni9Ti钢和未经阳极氧化处理的1Cr18Ni12Mo2钢在各种浓度的硫酸中的耐蚀性。图2表示阳极氧化和未经阳极氧化的1Cr18Ni9Ti钢在硫酸中的腐蚀速率。     

On the synergistic effects of abrasion and corrosion during wear

The interactive effects of abrasion and corrosion were studied as a function of abrasive load, corrosion time and the frequency of abrasive and corrosive treatments. The initial rate of corrosion is independent of abrasive load but the percentage contribution to wear of corrosion decreases with increasing abrasive load. It has also been found that increasing the frequency of exposure to abrasion and corrosion increases the wear loss for a constant total amount of abrasion and corrosion. These effects are discussed in terms of the nature of the work-hardened surface layer and the chemical activity of this layer.     

单相硼化物的制备及摩擦磨损性能研究

为了深入研究渗硼层中硼化物的性能,采用真空感应熔炼法制备单相硼化物材料。观察分析制备的硼化物微观组织,测试其力学性能。采用MMU-5G型销-盘式摩擦磨损试验机,在干摩擦条件下,研究了不同载荷下单相硼化物的摩擦学性能,观察其磨损表面形貌特征,探讨其磨损方式。结果表明：制备的硼化物为单一相,试样纯度高,试样的平均显微硬度为HV2065,平均断裂韧性值为1.68 MPa·m1/2;硼化物的断口处没有宏观的塑性变形,断口齐平光亮,表现为脆性断裂特征;干摩擦条件下随着载荷从10 N增加到30 N,硼化物的摩擦因数先降低后增加,20 N载荷时达到最小值,而其磨损量随着载荷的增加不断上升;随着载荷从10 N增加到30 N,磨损表面的粗糙度先逐渐上升后急剧上升; 10~20 N载荷下,硼化物的磨损以磨粒磨损为主,而25~30 N载荷下,硼化物的主要磨损方式从磨粒磨损转变为脆性破损。     

摩擦速度对Ti-6Al-4V合金腐蚀磨损的影响

采用腐蚀摩擦磨损试验机,进行了Ti合金/Al2O3摩擦副在林格溶液介质中的腐蚀磨损试验。试验在改变摩擦速度时对材料的耐腐蚀性能及钝化膜的再生能力进行了探讨。结果表明:摩擦破坏了Ti合金表面的钝化膜使电流密度上升。电流密度随摩擦速度的增大而增大。但是,钝化膜再生能力随摩擦速度的增大而减小。摩擦速度影响到磨损形态,速度小时主要以磨粒磨损形态为主,随着速度的增大磨损形态将过渡为腐蚀磨损和粘着磨损。     

干摩擦工况下Si3N4/PTFE配副材料摩擦磨损特性与转移膜形成分析

为使全陶瓷轴承在干摩擦工况下可靠运转,选用四氟乙烯(PTFE)材质的保持架为全陶瓷轴承提供润滑.利用Rtec销/盘摩擦磨损试验机,以PTFE盘与氮化硅(Si3 N4)销为摩擦副,研究Si3 N4/PTFE在不同载荷和转速条件下的摩擦磨损性能,通过SEM对Si3 N4表面的转移膜形貌进行观察,分析转移膜形成原因.结果表明...     

Effects of dissolved oxygen in saline on corrosive wear of steel

Wear behavior in a corrosive electrolyte where the corrosion reaction is controlled by the diffusion of oxygen cannot be explained only by the removal of corrosion products. The thickness of the oxide layer which varies with test conditions greatly affects the wear rate as well as the corrosion rate. In saline containing O₂ of 1 p.p.m. surface activation was confirmed. Adhesive wear or fatigue wear was found to have a predominant influence on wear behavior. Lubrication by a small amount of oxidation product can be expected to be beneficial. In O₂-saturated saline damage caused by corrosion fatigue is important owing to the intensely corrosive environment. Under O₂-saturated conditions the wear rate is constant under a load P < 3 4 kg, whilst w increases with increasing P above 3 4 kg, which may be considered to be due to the change of contact conditions. Under conditions of O₂-1 p.p.m. wear rate decreases slightly with increase of load because of the more effective lubrication by corrosion products.     

Corrosion–erosion wear behaviors of 13Cr24Mn0.44N stainless steel in saline–sand slurry

The corrosion–erosion wear behaviors of austenitic stainless steels, 316L and 13Cr24Mn0.44N, were investigated in water–sand slurry and saline–sand slurry, respectively. The corrosion–erosion wear mass-loss was measured to evaluate the influence of medium and materials. The worn surface and corrosion–erosion wear mechanism were analyzed using a scanning electron microscopy and a non-contact optical profilometer. Results show that the corrosion–erosion wear mass-loss of 13Cr24Mn0.44N is lower than that of 316L in both the slurries. The relative wear resistance increases with the increasing of the impingement velocity and arrives at maximum of 1.6. The dominant wear mechanism of 13Cr24Mn0.44N is abrasive wear in the water–sand slurry, whereas it becomes abrasive wear associated with little corrosive pitting in the saline–sand slurry. As the impingement velocity increased all the synergism ratios exhibit a tendency of increase, among which the synergism ratio of 13Cr24Mn0.44N is always lower than that of 316L at any given velocity. The results indicate that 13Cr24Mn0.44N possesses a predominant anti-corrosion–erosion wear property.     

Wear study of Ni–WC composite coating modified with CeO2

In the present investigation, Ni–WC composite powder was modified with the addition of CeO₂ in order to form a new composition of Ni–WC–CeO₂. The Ni–WC and Ni–WC–CeO₂ compositions were used for coating deposition by high-velocity oxy-fuel (HVOF) spraying process so as to study the effect of CeO₂ addition on microstructure, distribution of various elements, hardness, formation of new phases, and abrasive wear behavior. Further, the effect of load, abrasive size, sliding distance, and temperature on abrasive wear behavior of these HVOF-sprayed coatings was investigated by response surface methodology. To investigate the abrasive wear behavior of HVOF-sprayed coatings four factors such as load, abrasive size (size in micrometers), sliding distance (meters), and temperature (°C) with three levels of each factor were investigated. Analysis of variance was carried out to determine the significant factors and interactions. Investigation showed that the load, abrasive size, and sliding distance were the main significant factors while load and abrasive size, load and sliding distance, abrasive size and sliding distance were the main significant interactions. Thus an abrasive wear model was developed in terms of main factors and their significant interactions. The validity of the model was evaluated by conducting experiments under different wear conditions. A comparison of modeled and experimental results showed 4–9% error. The abrasive wear resistance of coatings increases with the addition of CeO₂. This is due to increase in hardness with the addition of CeO₂ in Ni–WC coatings.     

New Experimental Rig to Investigate Abrasive–Corrosive Characteristics of Metals in Aqueous Media

A new tribometer to investigate a conjoint effect of three-body abrasion and corrosion has been developed. In this design, a flat wear sample is loaded against a rotating cylindrical disc counterface and the abrasive slurry is delivered to the contact interface. Capabilities of the newly developed tribometer have been assessed through conducting abrasion–corrosion tests involving simultaneous electrochemical measurements. In this work, the stability of the passive layer on stainless steel under three-body abrasive wear in a near neutral electrolyte was investigated using potentiodynamic polarization tests. 316L Stainless Steel wear samples were abraded by coarse garnet particles in an aerated sodium sulphate electrolyte. The effects of load and speed on the polarization curves and passivity of 316L steel were determined. It was found that under abrasion–corrosion conditions 316L steel became more thermodynamically active and the passive corrosion rate has increased. Increasing the contact load resulted in a small increase in the passive corrosion current, while increasing the rotating speed had the opposite effect of decreasing the current. Linear polarization resistance method was used to analyse corrosion current changes with time during abrasion–corrosion testing. The existence of three distinct stages was explained by the third-body effect on the corrosion potential and current. First stage was revealed by continuous decrease of corrosion potential. Then, the potential reached a plateau for the second and third stages. In the first and second stages, particle constraint in the contact zone plays the major role and a linear rise in corrosion current with time has been recorded. After a certain amount of surface roughening, no further increase in particles entrapment is expected. Therefore, in the third stage steady-state corrosion current values are anticipated. The rig developed can also be used to simulate two-body abrasion–corrosion. The capabilities of the new rig have been compared against other experimental set-ups used in studies of combined abrasion–corrosion behaviour.     

25CrNi2MoV钢的微动磨损性能

采用微动摩擦磨损试验机在干摩擦条件下对新型高速重载传动轴用25CrNi2MoV钢进行微动磨损试验,研究了不同载荷(50~200N)和频率(15~30Hz)下该钢的微动磨损性能。结果表明:在频率为20Hz条件下,当载荷由50N增至200N时,25CrNi2MoV钢的平均摩擦因数由0.766减至0.661,磨损体积由19.65×10^-3 mm^3增至75.83×10^-3 mm^3;在载荷为30N条件下,当频率由15Hz增至30Hz时,平均摩擦因数由0.790增至0.905,磨损体积由11.43×10^-3 mm^3增至23.88×10^-3 mm^3;在不同试验参数下,25CrNi2MoV钢磨损表面均出现了氧化和犁沟现象,磨损机制包含氧化磨损和磨粒磨损;在频率为20Hz条件下,载荷为50,100N时,25CrNi2MoV钢的磨损机制以黏着磨损为主,载荷为150,200N时,主要磨损机制为疲劳磨损;在载荷为30N条件下,频率为15~25Hz时,磨损机制以磨粒磨损为主,当频率增至30Hz时,磨损机制以疲劳磨损为主。     

不同摩擦副条件下Ti-6Al-4V合金的微磨粒磨损行为

采用TE66微磨粒磨损实验机对医用Ti-6Al-4V钛合金在不同摩擦副条件下的微磨粒磨损行为进行研究,考察滑行距离、载荷对其微磨粒磨损的影响,通过观察磨斑形貌,分析其磨损机制。研究结果表明:Ti-6Al-4V合金的磨损量随滑移距离和载荷增加而增加,磨损率则相反,并且硬度较高的Si3N4陶瓷球对合金造成的磨损量和磨损率均低于ZrO2陶瓷球;在不同摩擦副条件下,随着滑行距离和载荷的增加,Ti-6Al-4V合金的磨损机制均由三体磨损转变为二三体混合磨损,所不同的是与Si3N4陶瓷球对摩时合金的混合磨损区域要少于与ZrO2陶瓷球对摩时。