XPS法研究高温弱酸性介质中化学镀Ni—Cu—P非晶态合金的腐蚀行为

利用ＸＰＳ法研究了化学镀Ｎｉ－Ｃｕ－Ｐ非晶态合金在１４０℃、ＰＨ＝５．０、ＣＯ２饮和Ｎａ２ＳＯ４溶液中片于不同电位下的表面膜组成。结果表明,处于不同电位下的Ｎｉ－Ｃｕ－Ｐ合金表面膜中皆有富Ｐ和富Ｃｕ现象发生,是膜中Ｎｉ选择性溶解的结果。Ｈ２ＰＯ２＾－和ＨＰＯ３＾２－吸附层的存在是合金发生钝化的原因。     

含H2S的强酸性溶液中Cl^—对铁腐蚀的影响

应用化学动电位扫描和交流阻抗法研究了Ｈ２Ｓ的Ｈ２ＳＯ４溶液中Ｃｌ＾－对腐蚀的影响。结果表明，在含Ｈ２Ｓ的０．５ｍｏｌ／ＬＨ２ＳＯ４溶液中，Ｃｌ＾－１能同时抑制铁腐蚀的阴，阳极反应，且Ｃｌ＾－的抑制作用存在浓度极值现象，极值点为１ｍｏｏ／Ｌ；     

碳钢在CO2-H2S体系中的腐蚀规律研究

采用氢扩散法,交流阻抗法和电子针分析研究碳钢在弱酸条件下的ａＣｌ溶液中通入ＣＯ２,以及加入微量Ｈ２Ｓ的腐蚀过程和渗氢量之间的关系,Ｃ烃及Ｈ２Ｓ的浓度在不同ＰＨ值对这个过程的影响,研究其腐蚀机理。实验表明,ＰＨ值在４～６．５之间的,ＣＯ２以及Ｈ２Ｓ对腐蚀过程和渗氢过程有着明显的加速作用,并且,随着ＰＨ值的降低,Ｃ烽Ｈ２Ｓ对渗氢量的增加有明显的促进作用。     

奥氏体不锈钢SUS316及SUS316L在含Cl^—的饱和H2S水溶液中 …

采用Ｕ型弯曲试样研究了固液及敏化奥氏体不锈钢ＳＵＳ３１６和ＳＵＳ３１６Ｌ在四种不同的含Ｃｌ＾－的饱和Ｈ２Ｓ水溶液中的应力腐蚀开裂（ＳＣＣ）行为。研究结果表明Ｃｌ＾－的加入和ＰＨ值的降低会增大实验钢处的应力腐蚀敏感性,而微量的Ｎａ２ＣＯ３则可降低其ＳＣＣ敏感性。     

磁场和缓蚀剂对Fe／0.5mol.L^—1H2SO4等体系极化行为的影响

测定了Ｆｅ／Ｈ２ＳＯ４，Ｆｅ／Ｈ２ＳＯ４＋Ｎａ２ＳＯ４，Ｆｅ／ＨＳＯ４＋Ｆｅ２（ＳＯ４）３和Ｆｅ／Ｈ２ＳＯ４＋ＮａＣｌ种体系在磁场或／和缓蚀剂作用下的极化曲线，指出腐蚀的主要控制是阴极过程，Ｈ２ＳＯ４中加入少量Ｎａ２ＳＯ４不影响其结果，但加入Ｆｅ２（ＳＯ４）３，ＮａＣｌ会因Ｆｅ＾３＋，Ｃｌ＾－的作用而影响结果，分析了磁场、缓蚀剂、Ｃｌ＾－和Ｆｅ＾３＋单一和联合对Ｆｅ／Ｈ２ＳＯ４阴极和阳极极化行为的     

Bi^3＋—Cl^——H2O系热力学平衡

运用同时平衡原理和质量平衡原理对Ｂｉ＾３－Ｃｌ－Ｈ２Ｏ体系进行热力学分析和计算，在此基础上绘制了Ｂｉ＾３＋－Ｃｌ－Ｈ２Ｏ体系在２５℃下的各种涫淀物的平衡浓度对数－ＰＨ图，分析确定了各大相沉淀物稳定存在的ＰＨ。结果表明，溶液中铋离子和硝酸根离子的浓度及溶液的ＰＨ值是影响各固相稳定存在的重要参数。由热力学图得出，可以直接从溶液中沉淀的Ｂｉ２Ｏ３，要得到高纯工的ＢｉＯＣｌ必须严格控制溶液的ＰＨ范围。     

J55套管在甘油田油层水中的腐蚀现象研究

通过对Ｊ５５套管在某油田层水中的腐蚀现象的研究,发现在此环境中,试样的平均腐蚀速率为０．１２８ｍｍ／ａ,试样表面存在轻微局部腐蚀现象,腐蚀产物主要由ＦｅＳ、ＣａＣｏ３和ＮａＣｌ组成。对试验前后油层水的成分分析发现,Ｈ２Ｓ、ＣＯ３＾２－、ＨＣＯ３在试验过程中被大量消耗,说明在这种环境中,套管腐蚀是ＣＯ２腐蚀、Ｈ２Ｓ腐蚀、细菌腐蚀、垢下腐蚀共同作用的结果。     

MoO3—MoO2—H2O—H2系平衡及400—700℃Mo—O系相图

使用自行设计的受控气氛热重装置研究了ＭｏＯ３－ＭｏＯ２－Ｈ２Ｏ－Ｈ２系平衡，在ＰＨ２Ｏ／ＰＨ２从０．４１２至０．６０９，温度从４００至５３４℃范围内直接测定了反应：ＭｏＯ３＋Ｈ２＝ＭｏＯ２＋Ｈ２Ｏ（ｇ）的平衡常数与温度间的关系为１ｇＫｐ＝０．７０２－７３９．８／Ｔ。获得２９８．１５Ｋ下ＭｏＯ３标准生成焓及绝对熵分别为：－８４５．７５ｋＪ·ｍｏｌｅ＾－１及７８．１６Ｊ·Ｋ＾－１·ｍｏｌｅ＾－１．实验     

锌在NaCl盐雾中的腐蚀规律

本文研究了锌在连续和间歇氯化钠条件下的腐蚀规律，其腐蚀规律均符合△Ｗ＝Ｋｔ＾ｎ。腐蚀主要产物为Ｚｎ５（ＯＨ）８Ｃｌ２，其次为ＺｎＯ。Ｃｌ＾－浓度变化对锌腐蚀失重有显著的影响。     

有,无磁场下缓蚀剂对Fe／0.05mol.L^—1HCl极化行为的影响

研究指出，Ｆｅ／０．０５ｍｏｌ．Ｌ＾－１ＨＣｌ体系中引入不同的缓蚀剂有可能产生不同的阴极过程和阳极过程。磁场一般不影响Ｆｅ的阳极溶解过程。但在成膜过程中会增大阳极电流密度。磁场也不影响阴极过程中Ｏ２扩散，Ｓｎ＾２＋还原，Ｓｎ＾２＋扩散，镀Ｓｎ层上氢还原等反应，但会影响Ｆｅ上氢还原反应。动态分析了缓蚀剂和磁场同时存在下，阴极析氢过程中磁场效应与缓蚀剂的交互作用，给出此时覆盖度与磁场作用系数的关系式。     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

Microstructure and Mechanical Properties of X80 Pipeline Steel Joints by Friction Stir Welding Under Various Cooling Conditions

X80 pipeline steel plates were friction stir welded(FSW) under air, water, liquid CO_2 + water, and liquid CO_2 cooling conditions, producing defect-free welds. The microstructural evolution and mechanical properties of these FSW joints were studied. Coarse granular bainite was observed in the nugget zone(NZ) under air cooling, and lath bainite and lath martensite increased signifi cantly as the cooling medium temperature reduced. In particular, under the liquid CO_2 cooling condition, a dual phase structure of lath martensite and fi ne ferrite appeared in the NZ. Compared to the case under air cooling, a strong shear texture was identifi ed in the NZs under other rapid cooling conditions, because the partial deformation at elevated temperature was retained through higher cooling rates. Under liquid CO_2 cooling, the highest transverse tensile strength and elongation of the joint reached 92% and 82% of those of the basal metal(BM), respectively, due to the weak tempering softening. A maximum impact energy of up to 93% of that of the BM was obtained in the NZ under liquid CO_2 cooling, which was attributed to the operation of the dual phase of lath martensite and fi ne ferrite.     

INDUSTRY NEWS

China Securities News reported on March 21, 2014： Guangdong Hongtu Wuhan Die Casting Co., Ltd. （Wuhan Hongtu）, a wholly owned subsidiary of Guangdong Hongtu Technology （Holdings） Co., Ltd., held a groundbreaking ceremony recently. With the registered capital of 50 million Yuan, Wuhan Hongtu has a total land area of 100,000 square meters and a plant construction area of 72,000 square meters. It is expected to have a production capacity of about 30,000 tonnes of aluminum castings annually after it is put into production.     

Microstructure,Mechanical Properties and Corrosion Behavior of Extruded Mg–Zn–Ag Alloys with Single-Phase Structure

Mg–Zn–Ag alloys have been extensively studied in recent years for potential biodegradable implants due to their unique mechanical properties,biodegradability and biocompatibility.In the present study,Mg–3Zn-x Ag(wt%,x=0.2,0.5 and0.8)alloys with single-phase crystal structure were prepared by backward extrusion at 340°C.The addition of Ag element into Mg–3Zn slightly influences the ultimate tensile strength and microstructure,but the elongation firstly increases from12%to 19.8%and then decreases from 19.8%to 9.9%with the increment of Ag concentration.The tensile yield strength,ultimate tensile strength and elongation of Mg–3Zn–0.2Ag alloy reach up to 142,234 MPa and 19.8%,respectively,which are the best mechanical performance of Mg–Zn–Ag alloys in the present work.The extruded Mg–3Zn–0.2Ag alloy also possesses the best corrosion behavior with the corresponding corrosion rate of 3.2 mm/year in immersion test,which could be explained by the single-phase and uniformly distributed grain structure,and the fewer twinning.     

Growth Morphologies of a Binary Alloy with Low Anisotropy in Directional Solidification

Two new classes of growth morphologies, called doublons and seaweed, were simulated using a phase-field method. The evolution of doublon and seaweed morphologies was obtained in directional solidification. The influence of orientation and velocity on the growth morphology was investigated. It was indicated that doublons preferred growing with its crystallographic axis aligned with the heat flow direction. Seaweed, on the other hand, could be obtained by tilting the crystalline axis to 45°. Stable doublons could only exist in a range of velocity regime. Beyond this regime the patterns formed would be unstable. The simulation results agreed with the reported experimental results qualitatively.