Z. Sun
,
S.L. Zheng
,
Y. Zhang
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
金属学报(英文版)
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.
关键词:
chromite
,
null
,
null
,
null
Hengzhi FU
,
Xingguo GENG
材料科学技术（英）
The present paper aims to the characterization of high rate direction solidification on AI-Mn and AI-Cu alloys. It is indicated that the relevant cooling rate of high rate directional solidification is defined within 10(0)～10(3) K/s that is located in the region between near-equilibrium slow growth rate and rapid solidification rate beyond equilibrium condition, and at the meantime there occurred a series of turning effect of interface stability and morphologies. With the increase of growth velocity the interface with planar front evolved to cells and dendrites at the stage of near-equilibrium and with further increase of growth rate they transformed reversely from dendrites to cell structure and then to absolute stability of planar interface. An explanation based on effective constitutional supercooling about the evolution of interface morphologies with the change of growth rate was proposed.
关键词:
J.H. Xie
,
Y.S. Wu
,
J.Q. He
,
X.Z.Yang and R.Z. Zhu (Department of Surface Science & Corrosion Engineering
,
University of Science and Technology Beijing
,
Beijing 100083
,
China)
金属学报(英文版)
This paper investigates the corrosion fatigue (CF) crack initiation behavior of 316L stainless steel in Hank's solution which simulates bodylike fluid. The CF experiments were conducted under the conditions of electrochemically accelerated, free immersion and pre-polarized pitting potential. The results showed that 316L stainless steel was susceptible to pitting corrosion in Hank's solution. Intergranular corrosion occurred obviously at the bottom of pits where the CF cracks initiated by the combined action of alternating stress and corrosive medium for the notch effect of stress concentrated in the grain boundaries.The CF crack propagation is both intergranular and transgranular.
关键词:
: aritificial joints
,
null
,
null
,
null
,
null
,
null
蒋秀
,
张艳玲
,
屈定荣
,
刘小辉
腐蚀科学与防护技术
doi:10.11903/1002.6495.2013.221
以某酸性气田集输管道工况为研究背景,通过实验模拟研究L360抗硫钢在S沉积环境的3.5％NaCl(质量分数)溶液中的腐蚀行为,结果表明:S的沉积导致L360钢发生了均匀腐蚀和小孔腐蚀;S使L360钢的均匀腐蚀速率增加约50倍;金属的腐蚀行为与S沉积厚度有关,但当S厚度超过临界厚度后,金属的腐蚀速率不再随S的厚度增加而变化;在3.5％NaCl溶液中,含S与不含S条件下L360钢的腐蚀行为明显不同,由于存在明显的腐蚀电位差,S沉积导致了电偶腐蚀的发生.
关键词:
S
,
腐蚀
,
电偶腐蚀
杨瑞成
,
毕海娟
,
牛绍蕊
,
靳塞特
,
申鹏
材料保护
过去，用电化学和浸泡方法综合研究409L，410S热轧不锈钢的腐蚀性能不够。通过电化学和浸泡试验研究了409L和410S2种热轧不锈钢在80％H2SO4，10％HCl，20％NaOH，6％FeCl3及混合酸（3．2％HCl＋3．8％HNO3）中的耐蚀性能，并与奥氏体不锈钢304作对比。结果表明：3种钢的耐腐蚀能力为304〉409L〉410S。409L比410S耐蚀性好的主要原因：409L含碳量低于410S，碳化物析出极少，且409L基本为单相等轴晶粒，组织比410S均匀；410S中还含30％左右的马氏体，产生大阴极（铁素体）、小阳极（马氏体）的腐蚀微电池，加速了其腐蚀。
关键词:
腐蚀行为
,
耐蚀性
,
腐蚀溶液
,
热轧不锈钢
,
极化曲线
林海
,
许杰
,
范白涛
,
张羽臣
,
王桂萍
,
霍宏博
,
殷启帅
表面技术
doi:10.16490/j.cnki.issn.1001-3660.2016.05.014
目的：研究L80钢在CO2/H2S环境中的力学特性。方法利用微机控制慢应变速率拉伸试验机，对特定腐蚀条件下的L80钢试样进行拉伸实验，分析各因素对L80钢力学特性的影响变化规律。结果在CO2/H2S环境中，随着含水率的增加，L80钢的屈服强度、抗拉强度、延伸率均下降，L80钢拉伸曲线出现劣化。随预拉应力的增大，L80钢的屈服强度变化不明显，而抗拉强度和延伸率降低，当预拉应力超过0.8σs时，L80钢的腐蚀速率显著增加，表现出较强的应力腐蚀敏感性；随着H2S分压的增加， L80钢的力学性能发生劣化，表现出氢脆敏感性，而受CO2分压的影响不明显；温度升高导致L80钢的拉伸曲线出现了轻度劣化，延伸率和屈服区宽度小幅降低，但抗拉强度变化不大。结论 L80钢在CO2/H2S环境中的力学特性受温度、CO2分压影响程度小。含水率和预拉应力的增大降低了L80钢的力学韧性，预拉应力的存在使L80腐蚀速率加快，缩短了耐腐蚀寿命。L80钢的力学性能对于H2S分压较对CO2分压更为敏感，试样的断裂是机械拉力和应力腐蚀共同作用的结果。
关键词:
L80钢
,
CO2腐蚀
,
H2S腐蚀
,
力学特性
,
腐蚀速率
,
应力腐蚀
武文鑫
,
刘美英
,
何晓旭
,
何云飞
材料开发与应用
选用TX-100/环己烷/正己醇/水反相微乳体系,以AgNO3为Ag源、Na2S·9H2O为S源、L-半胱氨酸为结构导向剂,室温下制备了高晶化度、直径为10-50nm的Ag2S纳米晶,并考察了影响其粒径大小的因素.紫外-可见吸收光谱表明,Ag2S纳米晶在290 nm处呈现强吸收,与体相Ag2S(1 240 nm)相比,其吸收边发生了明显的蓝移.通过调控微乳体系中ω0(水与表面活性剂物质的量比)、Ag+与L-半胱氨酸的物质的量比、反应物浓度等可以实现对产物尺寸和形貌的调控.
关键词:
Ag2S
,
纳米晶
,
反相微乳
,
L-半胱氨酸
赵景茂
,
魏辉荣
,
张娇娇
,
熊金平
,
唐聿明
,
左禹
腐蚀科学与防护技术
运用BP人工神经网络技术建立了预测L360钢在H2S/CO2环境中腐蚀的模型,神经网络拓扑结构为5-4-1, 网络模型训练成功以后,应用它预测L360钢在H2S/CO2中的腐蚀速度. 结果表明,人工神经网络模型预测的结果与实验数据相当符合, 误差在14%以内.由此可见,BP神经网络模型可以作为预测H2S/CO2环境致集输管线腐蚀速率的工具.
关键词:
L360钢
,
H2S/CO2 corrosion
,
BP artifical neural network
,
corrosion rate
林海
,
许杰
,
幸雪松
,
范白涛
,
杨进
,
王晓鹏
表面技术
doi:10.16490/j.cnki.issn.1001-3660.2016.05.013
目的：研究L80油管在CO2/H2S环境中的腐蚀行为。方法利用扫描电镜（SEM）、EDAX能谱分析L80油管内壁腐蚀产物形貌特征和化学组成，采用高温高压反应釜，以实际油水分离的水样为腐蚀介质进行模拟实验，研究原油含水率、CO2/H2S 分压和温度对 L80油管腐蚀速率的影响规律。结果在CO2/H2S环境中，L80油管内壁呈现明显的局部腐蚀特征，部分表面点蚀坑深度超过100μm，形成FeS、FeCO3等腐蚀产物。随着含水率的增加，L80油管腐蚀速率逐渐增大，含水率为30%时的腐蚀速率为0.0377 mm/a，含水率为100%时的腐蚀速率为0.0952 mm/a。CO2分压不变时，随着 H2S分压的增加，L80钢的腐蚀速率增大，H2S分压为0.04 MPa时的腐蚀速率为0.0377 mm/a，H2S分压为0.3 MPa时的腐蚀速率为0.0952 mm/a；H2S分压不变时，随着CO2分压的增大，L80钢腐蚀速率变化不明显且腐蚀速率较小。随着温度的升高，腐蚀速率先以较大幅度增大，再以较小幅度减小，从40℃增加至100℃时，腐蚀速率由0.0083 mm/a升至0.1264 mm/a，100℃左右时的腐蚀速率最大，120℃对应的腐蚀速率为0.106 mm/a。结论 L80油管在CO2/H2S环境中以均匀腐蚀和局部点蚀为主。L80油管腐蚀速率对H2S分压比CO2分压更敏感，CO2分压增大促使具有良好保护性的FeCO3保护膜的形成，降低了腐蚀速率。温度升高至一定范围，导致碳酸盐等难溶性盐溶解度降低，并覆盖在钢表面形成保护层，从而使腐蚀速率下降。
关键词:
L80油管钢
,
CO2/H2S腐蚀
,
腐蚀产物
,
腐蚀速率
,
腐蚀形貌
,
影响因素
