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1.
唐方苗  徐晖  陈雯  杨榕杰  杜荣归  林昌健 《功能材料》2011,42(2):291-293,297
应用极化曲线法和电化学阻抗技术,结合扫描电子显微镜方法,测试钢筋在模拟混凝土孔隙液中的钝化与去钝化行为,以及溶液pH值对钢筋电化学腐蚀行为的影响作用.结果表明,钢筋在pH值为12.50的模拟液中处于钝态,随着溶液pH值的降低,钢筋的耐蚀性下降.钢筋表面去钝化发生腐蚀的临界PH值在11.12-11.05范围内.  相似文献   

2.
采用Factsage热力学软件计算和实验相结合的方法,借助金相显微镜、扫描电镜、透射电镜等检测技术,研究了900℃时效条件下超级奥氏体不锈钢904L热轧板的组织变化情况。结果表明:904L不锈钢在1080℃×40min固溶处理为单一奥氏体组织;900℃时效处理过程中,析出相优先在晶界上形成,随着时效时间延长,析出相数量逐渐增加,尺寸不断增大,最终在晶界上形成网状分布;TEM和EDS表征确定为富Cr、Mo和低Ni的σ析出相,形貌以条状和块状分布为主;热力学计算结果表明904L不锈钢在平衡状态下主要析出相为σ相,与实验结果吻合。  相似文献   

3.
姜昕蕙  卢立新  李伟哲 《包装工程》2022,43(19):255-261
目的 通过电化学方法探究气相防锈包装过程中温度和包装内缓蚀气压对气相防锈效果的影响,为实际工况中获得较长的气相防锈有效寿命期提供数据参考。方法 以10#钢和铸铁为金属试样作为工作电极,通过交流阻抗谱和动极化曲线对不同温度和不同缓蚀气压下试样缓蚀过程进行研究,并分析其电化学参数变化规律,对缓蚀效果进行评价和比较。结果 交流阻抗谱结果表明,温度升高和缓蚀气压下降时,金属试样表面阻抗值减小,且在高温低频区出现Warburg阻抗,腐蚀机理发生改变。动极化曲线结果表明,随着温度升高和缓蚀气压下降,金属试样的腐蚀电流减小,腐蚀电压负移。结论 温度升高及包装内的缓蚀气压下降均会造成金属气相防锈效果下降,且升温后缓蚀剂对缓蚀气压的变化更敏感,为延长气相防锈包装的有效寿命期应关注高温工况,并确保气相防锈包装内缓蚀气压稳定。  相似文献   

4.
目前,对AISI 316奥氏体不锈钢单一面心结构γΝ相改性层耐磨抗蚀性能的报道差异较大,有些甚至相互矛盾。采用等离子体源渗氮技术,于450℃,6 h改性AISI 316奥氏体不锈钢,获得了厚度约为17μm、峰值氮浓度20%(原子分数)、最大显微硬度1 510 HV0.1 N、单一面心结构的γΝ相改性层。分别采用WTM-2E球盘式磨损仪和PARSTAT2273电化学工作站,研究了干摩擦条件下γN相/Si_3N_4陶瓷球的摩擦磨损行为和在3.5%NaCl溶液中的电化学腐蚀行为,揭示了γN相改性层的耐磨抗蚀机理。结果表明:γΝ相改性层的磨损机制由原不锈钢的黏着磨损转变为氧化磨损,摩擦系数由0.88降低至0.65,磨损体积由0.13 mm~3降低到9.50×10-3mm~3,耐磨性能显著提高;γΝ相改性层阳极极化曲线未发生点蚀击穿过程,容抗弧直径增大,相位角平台变宽;采用等效电路Rs-(Rct//CPE)拟合的电荷转移电阻Rct由原不锈钢的1.006×105Ω·cm~2增至1.377×106Ω·cm~2,计算的双电层电容Cdl由88.4m F/cm~2降低至77.8 m F/cm~2,抗蚀性能明显得到了改善。  相似文献   

5.
3Cr低合金钢在含饱和CO_2的NaCl溶液中的腐蚀电化学行为   总被引:3,自引:0,他引:3  
研究了含饱和CO2的NaCl溶液pH值对3Cr低合金钢腐蚀及其电化学行为的影响。结果表明: 当NaCl溶液的pH值较低(2, 3.9)时, 腐蚀产物膜为单层结构, 呈龟裂状; 当pH值较高(6.5)时, 腐蚀产物具有三层结构, 外层腐蚀产物为颗粒状, 内层仍呈龟裂状。NaCl溶液的pH值对3Cr低合金钢的腐蚀电化学行为也有显著影响。 NaCl溶液的pH值升高能改变电极过程中的主要阴极反应, 使腐蚀电位逐渐负移, 且电荷转移电阻的增大使腐蚀电流密度减小。  相似文献   

6.
刘强  李波  陈希章  刘靖  郭辉  袁勇 《功能材料》2012,43(5):673-676
制备了一种Cr-Co-Ni-Mn含钴奥氏体不锈钢。与304不锈钢比较,研究了其抗空蚀性能,用TEM观察了空蚀试样的组织结构,并测定了该钢种的强度,利用时效处理研究其组织稳定性。结果表明Cr-Co-Ni-Mn含钴奥氏体不锈钢屈服强度、抗拉强度比常用的304不锈钢高,奥氏体组织稳定,空蚀孕育期长,耐空蚀效果好。TEM观察到试样空蚀作用层有ε马氏体组织,这些形变组织有利于吸收应变能,提高材料耐空蚀能力。综合该钢的性能,在耐空蚀领域有潜在的应用前景。  相似文献   

7.
目的 研究含铜奥氏体不锈钢在室温及低温下的拉伸、成形性能。了解杯突试验背景下,含铜奥氏体不锈钢微观组织演变规律。方法 在室温及液氮环境−140 ℃温度下,对含铜奥氏体不锈钢进行拉伸、埃里克森(Erichsen)杯突试验。结合试验结果、扫描电镜及透射电镜表征,分析了室温及低温环境对含铜奥氏体不锈钢各项性能的影响。结果 含铜奥氏体不锈钢在−140 ℃时的极限抗拉强度提升约49.7%,屈服强度提升约35.5%,延伸率降低约27.3%。在室温下,拉伸断裂方式为韧性断裂。在低温下,拉伸断裂方式转变为脆韧混合断裂。在杯突试验中,突值从室温的12.78 mm增加到−140 ℃低温的13.45 mm,增加了0.67 mm。结论 通过EBSD分析内部微观组织结构可知,在杯突试验过程中,应力的不断集中及应变的变化,促使位错产生滑移、孪晶,并使奥氏体发生马氏体相变。越靠近断裂裂纹区域,应力集中越明显,奥氏体转变为马氏体越明显,马氏体含量越多。孪晶诱导塑性(TWIP)及相变诱导塑性(TRIP)提高了不锈钢的强度和塑性。  相似文献   

8.
通过钢的成分的设计,研制了一种用于制造锅炉汽包和压力容器的奥氏体粗晶粒钢,这种钢经一定热处理后,可获得高强度高韧性的使用要求。  相似文献   

9.
The cyclic fatigue life of stable austenitic 20Cr-16Ni-6Mn-0.14N steel in two melts, obtained by different techniques, was studied in a wide range of stress amplitudes, in vacuum, at 293 and 11 K. The influence of grain size on the cyclic yield stress was formulated at both temperatures. The effects of a vacuum and low temperatures on the fatigue characteristics and the crack growth micromechanism were also investigated.  相似文献   

10.
利用自行设计的高温凝固相转变测定实验装置,研究了304奥氏体不锈钢在不同冷却速度下的高温凝固相转变过程,得到了凝固过程中液相( L)到高温铁素体(δ)到奥氏体(γ)的相变温度。在此基础上分析了304奥氏体不锈钢在不同冷却速度下的高温凝固相转变规律,从而建立了304奥氏体不锈钢的低冷速凝固相转变规律曲线—SPT(Solidification phase transforma?tion)曲线。结果表明:对试样进行液氮酒精淬火有效地保留了试样高温时各相的状态。可以清楚的显示在不同冷速下的不同温度淬火时液相和固相的各相成份比例及在不同淬火温度下各成份体积比例的变化。通过研究体积比例变化,可以得到304奥氏体不锈钢在不同冷速下的液相线、固相线及各种反应开始和结束的转变温度(即SPT曲线)。由SPT曲线也可以看出,随着冷却速度的增大,相转变模式会发生变化,相图会向左移动,各相变反应的温度区间减小。  相似文献   

11.
S35140钢是一种基于25Ni-20Cr的奥氏体耐热钢,为了获得高强度,通常会提高碳含量,但碳含量较高不利于高温时效稳定性和长期耐腐蚀性能.本文在S35140钢的基础上,大幅度降低碳含量,并通过调控N和Nb等微合金元素含量,以及加入Ti元素,促使析出新的强化相,弥补减少碳含量所导致的强度降低.同时引入一定量的Al元素...  相似文献   

12.
    
The effect of C,Mn and heat-treatment onwork-hardening of austenitic Mn steel and thework-hardening mechanism have been investigatedunder non-severe impact loading condition.Theresults show that the ability of work-hardening in-creases with the increase of C and aging tempera-ture but decreases with Mn.The work-hardeningwith high austenitic stability results mainly fromdislocations,and that with low austenitic stabilityresults mainly from combined effects of strain-in-duced martensite and high density of dislocationsunder non-severe impact loading conditions.Thewear resistance of medium manganese steel (Mn7)is 1.64-2.46 times that of Hadfield steel (Mnl3).  相似文献   

13.
Key Technique of Austenitic Stainless Steel on-line Solution Treatment   总被引:1,自引:0,他引:1  
Generally the methods of solution treatment of austenitic stainless steel are bifurcated on-line solution and off-line solution . For a founded enterprise, it is necessary to find out how to get across alterations and search a measure of on -line solution disposal with less investment and higher efficiency. By studying and analysingin laboratory, several key points and the methods settle them are presented, which offers a new route to realize austenitic stainless steel on-line solution. By reducing the cost greatly, it makes the enterprise larger benefits.  相似文献   

14.
  总被引:1,自引:0,他引:1       下载免费PDF全文
A number of studies have been reported on the use of nanocrystalline plasma electrolytic nitrocarburising technology for surface hardening of stainless steels for higher corrosion resistance resulted from this technique. However, very few studies have focused on the optimization of the nanocrystalline plasma electrolytic nitrocarburising process parameters. In this study, a design of experiment (DOE) technique, the Taguchi method, has been used to optimize the nanocrystalline plasma electrolytic nitrocarburising not only for surface hardening but also for the corrosion protection of 316L austenitic stainless steel by controlling the coating processes factors. The experimental design consisted of four factors (Urea concentration, electrical conductivity of electrolyte, voltage and duration of process), each containing three levels. Potentiodynamic polarization measurements were carried out to determine the corrosion resistance of the coated samples. The results were analyzed with related software. An analysis of the mean of signal-to-noise (S/N) ratio indicated that the corrosion resistance of nanocrystalline plasma electrolytic nitrocarburised 316L stainless steel was influenced significantly by the levels in the Taguchi orthogonal array. The optimized coating parameters for corrosion resistance are 1150 g/L for urea concentration, 360 mS/cm for electrical conductivity of electrolyte, 260 V for applied voltage, 6 min for treatment time. The percentage of contribution for each factor was determined by the analysis of variance (ANOVA). The results showed that the applied voltage is the most significant factor affecting the corrosion resistance of the coatings.  相似文献   

15.
火电厂烟气脱硫系统的设备腐蚀问题比较严重,选材较为关键.为此,选用304不锈钢和2205双相不锈钢,考察了其在烟气脱硫模拟介质(死亡绿液)中不同温度和不同浸泡时间的腐蚀行为.结果表明:304不锈钢在死亡绿液中随温度变化腐蚀性很敏感,易发生点蚀,不宜用作烟气脱硫装置及其零部件;2205双相不锈钢在烟气脱硫模拟介质中不同温度和时间范围内都有良好的耐蚀性,可用作烟气脱硫装置及其零部件的材料.  相似文献   

16.
35钢在城市交通工程中应用越来越多,酸雨对其腐蚀严重,过去对其研究不多。为此,配制了模拟酸雨溶液,研究了35钢在模拟酸雨溶液中的腐蚀行为,探讨了酸雨酸度和浸泡时间对35钢腐蚀行为的影响。采用极化曲线、电化学交流阻抗(EIS)及扫描电镜(SEM)方法对35钢的腐蚀进行了测试分析。结果表明:随着模拟酸雨溶液pH值的降低,35钢的腐蚀电流逐渐增大,腐蚀速率增大,腐蚀电位负移;随着浸泡周期的延长,阻抗谱中锈层阻抗增大,腐蚀速率降低,表面生成的腐蚀锈层对基体起到一定的保护作用。SEM和EDS分析表明,35钢在低pH值的酸雨中腐蚀严重,表面蚀坑密集且深,腐蚀产物粗大疏松,致密性差,为硫酸盐,而pH值升高时腐蚀相对较轻,蚀坑较小。  相似文献   

17.
混凝土中钢筋腐蚀速率的现场无损检测技术   总被引:6,自引:0,他引:6  
在对国内外所使用的检测方法及仪器进行广泛调研的基础上,对腐蚀电位法、交流阻抗法、电流阶跃法及线性极化法进行了比较,得出线性极化法是最简易行适合现场测试条件的钢筋腐蚀的无损检测技术。并在此基础上提出线性极化法的设计方案,针对线性极化法在现场应用中可能存在问题,提出了相应的解决办法。  相似文献   

18.
为了解决我国能源需求量增加与环境污染加剧的现状,高参数的超超临界火力发电厂及高效先进核电机组亟待被研发,而其高温高压强腐蚀的严苛的服役环境给高温结构材料带来了严峻的挑战。新型含铝奥氏体不锈钢(Alumina Forming Austenitic Steel, AFA钢)因其优异的抗氧化性能和高温力学性能,有望成为超超临界火力发电厂以及超临界水冷堆等发电站的关键部件候选材料。时效处理及热力耦合过程中AFA钢基体组织和沉淀相会发生复杂的演变,对其高温力学性能产生影响。本文总结了成分设计、时效温度以及时效时间对AFA钢沉淀相析出行为的影响,阐述了AFA钢在热力耦合过程中基体组织的变化、沉淀相的演变及蠕变断裂的原因,并对AFA钢沉淀相析出的优化及蠕变性能的提升给出了建议和展望。  相似文献   

19.
The paper discusses the effects of the components of the electrode impedance for a primary contact sensor in a solution as regards measurement of the resistivity, and a method is proposed for determining the constant and estimating the values of the components. __________ Translated from Izmeritel’naya Tekhnika, No. 3, pp. 61–63, March, 2008.  相似文献   

20.
Abstract

The adverse effects of nickel ions being released into the human body have prompted the development of high-nitrogen nickel-free austenitic stainless steels for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel in medical stainless steels, the advantages of nitrogen in stainless steels, and emphatically, the development of high-nitrogen nickel-free stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength and good plasticity, better corrosion and wear resistances, and superior biocompatibility compared to the currently used 316L stainless steel, the newly developed high-nitrogen nickel-free stainless steel is a reliable substitute for the conventional medical stainless steels.  相似文献   

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