G3镍基合金钝化膜的耐蚀性研究

利用极化曲线和电容测量法(Mott-Schottky曲线),研究了G3镍基合金油管材料在室温空气中以及130℃和205℃同时含H2S和Cl-的腐蚀介质中浸泡720 h所形成的3种钝化膜的电化学行为和半导体性质.结果表明:在室温空气中和130℃腐蚀介质中形成的钝化膜都具有良好的耐蚀性,而在205℃腐蚀介质中形成的钝化膜耐蚀性下降;前者具有双极性n-p型半导体特征,而后者为n型半导体,且由于掺杂浓度增加,耐蚀性能下降.     

Effect of Chloride on Semiconducting Properties of Passive Films Formed on Supermartensitic Stainless Steel in NaHCO3 Solution

 The effects of chloride ion on the electrochemical behavior and the semiconducting properties of the passive film on supermartensitic stainless steel in 0. 5 mol/L NaHCO3 solution were investigated using potentiodynamic polarization, the potentiostatic current transients and Mott-Schottky analysis. The results indicated that chloride ion narrowed passivation region and improved pitting susceptibility. The steady state current densities were independent of film-formed potentials, which was in good agreement with the assumption of the point defect model (PDM). The capacitance results showed the fact that the passive films had a multilayer character. The defect density decreased with increasing passive film formation potential. The chloride ion induced changes of the acceptor densities and donor densities of the passive films.     

氢对不锈钢钝化膜纳米力学性能的影响

利用电化学实验方法和纳米力学探针技术,通过测量载荷-位移关系曲线,研究了氢对不锈钢钝化膜纳米力学性能的影响。结果表明:随氢含量的增加,不锈钢钝化膜的临界破裂载荷降低,位移偏移量减小,氢导致钝化膜的径向抗拉强度(应力)和弹性模量降低,钝化膜随氢含量的增加而逐渐软化。

     

镍基合金粉末等离子弧堆焊层的性能研究

采用等离子弧堆焊技术,在Q235钢表面堆焊镍基合金粉末,通过工艺试验、硬度试验、磨损试验和显微组织观察分析,研究了等离子弧堆焊层的常规性能。试验结果表明:镍基合金粉末堆焊层硬度和耐磨性较基体有显著提高。     

Corrosion Resistance and Semiconducting Properties of Passive Films Formed on 00Cr13Ni5Mo2 Supermartensitic Stainless Steel in Cl- Environment

The semiconducting properties of passive films grown on 00Crl3Ni5Mo2 supermartensitic stainless steel were investigated in comparison with conventional 2Cr13 martensitic stainless steel. Cyclic vohammetry and electro- chemical impedance spectroscopy （EIS） were used for the studies. 00Crl3NiSMo2 steel exhibited a good corrosion resistance performance, attributing to its passive capability. The results of Mott-Schottky analysis demonstrated n- type semiconductors for the passive films with doping densities of about 1020- 1021 cm -3, and the thickness of space- charge layers was also calculated. The experimental results confirmed that Mo plays an important role in improving the corrosion resistance of 00Crl3Ni5Mo2 steel due to its impact on the doping density.     

气/液比对喷射成形超高强铝合金显微组织及性能的影响研究

采用喷射成形技术制备了Al11Zn2．8Mg1．8Cu超高强铝合金，研究了G／M比对材料显微组织及室温机械性能的影响。结果表明：喷射成形沉积坯件微观组织均匀、细小，晶粒基本为球形或类球形，T相和S相数量大幅度减小（与铸造相比）；随着G／M比的增大，喷射成形沉积坯件的晶粒尺寸逐渐减小，低熔点共晶相的数量也逐渐减少，但收得率逐渐降低。研究结果表明理想的G／M值为4．5～5．0kg／kg，此时晶粒度为15～25μm，致密度可达到94％～96％，收得率可以达到60％～65％，极限抗拉强度为800～830MPa，同时延伸率在9％以上。     

微量Mg、Ag对Al—Cu—Li系合金组织和性能的影响

研究了以Al-1.0Li-4.0Cu合金为基础，加入微量元素镁或银的合金薄板材料在180℃下时效不同时间的显微组织特征和室温拉伸性能，实验结果表明；单独加入镁或单独加入银都使基础合金获得较大的强化效果，但镁的单独作用比银要大；Mg和Ag共同加入则产生最大的强化效应，这说明Mg和Ag之间有强烈的相互作用。     

热暴露对铸造TiAl合金表面完整性及拉伸性能的影响

分析了热暴露温度、时间对TiAl合金表面完整性及室温拉伸性能的影响。结果表明,热暴露温度为700℃时,热暴露后试样表面残余压应力有所降低,温度升高至750和800℃时,试样表面残余压应力变化不大。经750和800℃热暴露后,试样表面生成厚度均匀的多重表面层;观察热暴露后试样断口可以观察到沿表面层和基体界面的连续裂纹和表...     

几种含铌低弹性模量钛合金组织与性能研究

通过对含Nb钛合金进行成分优选，设计出4种具有较低弹性模量的新型Ti-Nb-X系钛合金，并对4种新型钛合金的组织与性能进行了研究。研究结果表明，4种新成分钛合金的弹性模量均低于80GPa，符合设计要求。4种合金的组织均匀，组织类型为等轴组织。个别晶粒中存在一定的孪晶与合金加工变形过程有关。此类合金在医学外科植入物、眼镜架用材、运动器材等领域有推广价值。     

热处理对Ti—6242S合金显微组织和性能的影响

研究了简单退火、双重退火、固溶时效和形变热处理对Ti-6242S合金显微组织和性能的影响,选择出双重退火热处理工艺,即在900－980℃,1h,空冷＋593℃,8h,空冷处理的棒材,显微组织为等轴α β转,并且有最佳的综合性能。     

稀土多晶Ni-Mn-Ga合金磁性能的研究

研究了多晶Ni50Mn29Ga21-xTbx合金系列的居里温度和饱和磁化强度.结果表明,适当地添加稀土Tb在明显提高材料力学性能的同时,保持了材料的原有居里温度和饱和磁化强度基本不变.微区成份能谱分析表明,稀土Tb在材料中主要存在于晶界.晶界上的Tb对材料的磁性能没有贡献,同时对晶粒内部Mn原子局域磁矩及其交换作用也没有明显的影响.     

锆基块体非晶合金力学性能的研究进展

锆基块体非晶合金具有优良的非晶形成能力,可在很小的冷却速率条件下获得.锆基非晶合金具有高强度、超塑性、高弹性、高硬度、高耐磨性和高耐腐蚀性能等,有着广阔的应用前景.总结了锆基非晶合金的形成机制,着重对锆基非晶合金的力学性能、耐腐性能等进行了综述.     

原子状态对Fe—Al合金结构及性能的影响

从结晶学等效性的角度系统论述了应用经验电子理论确定的富铁区Ｆｅ－Ａｌ合金中不同原子的状态，分析了原子状态对合金结构及各种性能的影响，得出Ｆｅ－Ａｌ合金相结构及性能的变化都来源于原子状态变化的结论。     

Crystalline Behavior and Magnetic Properties of Nd60Fe30-x Al10Cox（x = 0,5,10） Bulk Amorphous Alloys

Crystalline behavior and magnetic properties of Nd60Fe30-xAl10Cox( x = 0, 5, 10) bulk amorphous alloys were investigated by differential scanning calorimeter (DSC), X-ray diffraction (XRD) and the vibrating sample magnetometer (VSM). Neither glass transition nor supercooled liquid region before crystallization was observed for the as-cast Nd60Fe30-xAl10Cox ( x = 0,5,10) bulk amorphous alloys. The glass forming ability can be improved significantly by the addition of Co. The as-cast Nd60Fe30-xAl10Cox (x = 0,5,10) alloys show hard magnetic behavior. With the addition of Co content, intrinsic coercivity (iHc) increases while the saturation magnetization(σs) and remanence (σr) decrease. The Curie temperature for the as-cast Nd60Fe30-xAl10Cox alloys increases from 451 K for x =0 to 468 K for x = 10. Some pre-cipitation of crystalline phases does not affect the hard magnetic properties of Nd60Fe30-xAl10Cox(x = 0,5,10) alloys, while the hard magnetic behavior disappears quickly after the alloys being completely crystallized.     

Influence of Bath Composition on Magnetic Properties of Electrodeposited Co-Pt-W Thin Films

Effect of bath composition （[Co^2＋]/[-Pt^Ⅳ ] and [-WO4^2- ], [cit^-]） and pH on the magnetic properties of electrodeposited Co-Pt-W thin films has been investigated. Electrodeposited Co-Pt-W thin films exhibited strong perpendicular magnetic anisotropy when the ratio of [-Co^2＋ ] to [-Pt^Ⅳ ] was 10 ; cathode current efficiency and perpendicular magnetic anisotropy showed little variations when [WO4^2- ] was lower than 0. 1 mol/L, but perpendicular magnetic anisotropy had strengthened when [WO4^2-] was over 0. 1 mol/L, which could be explained by the fact that the hydrogen evolution could produce pores as magnetic domain pinnings; citrate as complexing reagent can promote the polarization of [Co^2＋] and [Pt^Ⅳ]. As a result, the equilibrium electrode potentials of cobalt and platinum moved to negative direction, which led to the co-deposition of Co, Pt, and W. It was also found out that the as-deposited Co- Pt-W hard magnetic thin films were very homogeneous, smooth, and had the maximum coercivity for the bath pH 8. 5 and the concentration of citrate 0. 26 mol/L.     

Erosion and Corrosion of Mild Steel and Stainless Steel in Sodium Carbonate／Bicarbonate Solution Bearing Alumina Particle

With a rotating cylinder electrode apparatus, the polarization behaviors of the mildsteel and the stainless steel 0Crl8Ni9 in NaHCO3 (0.5M) NazCO3 (0.5M) solution with andwithout erodent particles were investigated and compared. The results show that the rotationspeed of cylinder hardly affects the polarization behavior of sample in solution without particlesbut exerts a great influence on that with particles. Increasing rotation speed, the free corrosionpotential shifts to positive direction and the oxygen limiting current density increases. Both themild steel and stainless steel 0Crl8Ni9 experience a significant increase of the mass loss by in-creasing erosion, and erosive wear was dominated by severe micro-plowing. The insufficientmechanical strength of both materials leads to a low resistance to particle removal. Increasingperipheral velocities of the rotating cylinder enhances the corrosion rate of the mild steel. Thestainless steel 0Crl8Ni9, due to a high erosive wear, also suffers from similar erosion-corrosiondamage, despite that its corrosion resistance is much higher than that of the mild steel.     

Study on ESR Properties of a-Si_(1-x)Gd_x Films

ESR studies have been undertaken for various chemical composition of electron beam evapo-rated a-Si_(1-x)Gd_x films with 0相似文献   

Hot Working Characteristics of Corrosion-Resistant Alloys G3 and 825

  The G3 and 825 alloys, with excellent combination of mechanical properties and corrosion resistance, can be used in hot, and acid environments. Thermal simulation tests were conducted on the alloys G3 and 825 in the THERMECMASTOR Z simulator, at temperature between 1030 and 1300 ℃, with strain rate from 1 to 50 s-1 and strain ε=08. The variations of flow stress with deformation temperature and strain rate were presented. Change of alloy structure with hot deformation and effect of strain rate on alloy dynamic recrystallization have been studied through microstructure observation by OM, SEM and TEM. Moreover, hot plasticity characteristics of alloy were analyzed by temperature reduction of area curves. The results showed that available hot working temperature for G3, G3 Z and 825 was 1100 to 1240 ℃, 1130 to 1220 ℃ and 1050 to 1240 ℃, respectively. The reliable information on hot working in the alloy pilot production in steelwork is given.     

镍钛形状记忆合金薄膜的相变温度和力学性能

利用直流磁控溅射法溅射沉积了NiTi形状记忆合金薄膜，对NiTi形状记忆合金薄膜进行晶化热处理以使其获得形状记忆效应。研究了550℃晶化热处理1h后Ti-48.2%Ni薄膜的相变温度和力学性能，研究结果表明，NiTi薄膜550℃晶化热处理1h后，升温过程中发生M→A的相变，而降温过程中则先发生A→R相变，再发生R→M的相变，薄膜的断裂强度随测试温度的升高而增大，残余应变随温度的升高而减小，当温度大于Af点时，表现为超弹性。     

化学计量比对AB5型贮氢合金相结构及电化学性能的影响

对低钴稀土系贮氢合金Ml(Ni0.78Co0.08Al0.06Mn0.08)x(4.8≤x≤5.4)的相结构及电化学性能进行了研究.结果表明在4.8≤x≤5.2的合金中除CaCu5型结构的主相之外,还出现LaNi3第二相,而且合金中第二相(LaNi3)的析出量随着x值的增大而减少,化学计量比x=5.4的合金则有富镍相析出,B侧合金化使低钴贮氢合金形成单相AB5型合金的化学计量比由x=5.0增大至5.2～5.4之间.四种不同化学计量比合金的活化性能都较好,合金的最大放电容量随化学计量比x的增大而增加,过化学计量比(x=5.4)合金具有最大的放电容量,最优的放电电压特性及最佳的循环稳定性,且其高倍率放电性能也较好.