糖苷对碱性溶液中钢筋表面钝化膜性能的影响

利用动电位极化和表面形貌观察技术,结合电容-电位曲线测量和Mott-Schottky分析,探讨了糖苷化合物对钢筋在含3.5%NaCl的Ca(OH)₂饱和溶液中的缓蚀行为和表面钝化膜性能的影响。结果表明,糖苷阻锈剂的加入可有效减缓钢筋的腐蚀,促进钢筋表面的钝化,提高钢筋耐Cl^-侵蚀能力;阻锈剂虽未改变钢筋表面钝化膜的半导体性能,但钝化膜内载流子密度却显著下降;钝化膜致密性分析表明,随糖苷浓度增大,钢筋表面钝化膜稳定性和致密性逐渐增强,耐蚀性提高。     

原位STM研究钢筋在模拟混凝土孔溶液中腐蚀和缓蚀动态行为

应用STM原位观察在不同氯离子浓度和pH值以及加入缓蚀剂前后的模拟混凝土孔溶液中的钢筋表面微观形貌．在pH=12．40的混凝土模拟孔溶液中，钢筋表面趋向均一，钝化膜的薄弱部分得到强化；在含3．5％NaCl，pH=10．40的混凝土模拟孔溶液中由于局部腐蚀的发生，可观察到不规则的沉积物的形成、生长；LD-2型复合缓蚀剂能消除腐蚀活性，促使表面微观缺陷消亡，增加钝化膜的耐蚀能力．研究结果说明，STM可在纳米尺度上观察表面形貌变化，可成为原位研究钢筋在模拟混凝土孔溶液中腐蚀和缓蚀的动态行为的重要手段．     

用XPS研究钢筋钝化膜和C1~-对钝化膜的影响

采用光电子能谱(XPS)研究钢筋钝化膜的组成与结构,以及氯离子对钝化膜的影响。结果表明,在本实验条件下钢筋钝化膜为双层结构,外层以γ-FeOOH为主,内层主要为FeO;氯离子对胶的破坏过程可能是先在钝化膜表面吸附,然后穿透到膜中,在铁/氧化物界面即膜的内层形成FeCl_2,而使钝化膜局部溶解;复合缓蚀剂的加入使钢筋钝化膜表面γ-FeOOH的含量增大,膜中夹杂一定深度的有机铵盐,硅酸盐只在表面沉积。     

硅烷无铬钝化膜的耐腐蚀性能及成分探究

目的探究无铬钝化膜的微观形貌和成膜机理。方法通过电化学实验评价钝化膜的耐腐蚀性能;通过扫描电镜观察钝化膜的微观形貌,探究其与耐腐蚀性之间的关系;通过XRD,EDS,XPS分析钝化膜的成分及组成。结果电化学实验表明,镀锌板经钝化处理后,钝化膜抑制锌层的阳极反应,有效降低腐蚀速率。SEM分析发现,钝化膜表面的平整度与其耐蚀性能无直接关系。XRD不能用于分析该工艺钝化膜的元素及组成。EDS和XPS分析结果表明,钝化膜主要含有Zn,C,O,N,Si等元素。结论有机大分子构成钝化膜的主要骨架,Si O2和硅酸盐等吸附于立体骨架结构中,形成一层致密的钝化膜,起到抑制锌层阳极反应的作用。     

化学钝化对S280超高强度不锈钢综合性能的影响

采用电化学极化方法,测试了不同工艺参数条件下钝化膜的电化学特性;采用AFM、XPS分别对钝化膜微观形貌和成分进行了表征;同时检测了钝化试样的耐蚀性、氢脆性和疲劳性能。结果表明,S280不锈钢钝化膜结构致密,主要成分是各种金属氧化物、氢氧化物或羟基氧化物,并且检测到不同类型金属间氧化物的存在。钝化后的S280不锈钢耐蚀性大幅度提高,满足氢脆要求,疲劳性能轻微降低。     

钼酸钠对钢筋在氯离子混凝土模拟液中腐蚀行为的影响

利用动电位极化曲线、交流阻抗技术及Mott-Schottky曲线等方法,研究了钼酸钠对钢筋在5%NaCl混凝土模拟液中的电化学腐蚀行为和表面钝化膜性能的影响.结果表明:随钼酸钠浓度增大,缓蚀效率逐渐增加,对钢筋的腐蚀有较好地抑制作用,药剂在钢筋表面的吸附可有效屏蔽氯离子的侵蚀作用;Mott-Schottky结果表明,在-0.5~0.1 VSCE范围内,混凝土模拟液中钢筋表面钝化膜Cs-c2-E曲线呈正线性相关,表明钢筋表面钝化膜为n型半导体,且随钼酸钠浓度增大,钢筋钝化膜载流子密度逐渐减小,钝化膜稳定性增强,耐蚀性逐步提高;钝化膜致密性分析表明,随钼酸钠浓度增大,钝化膜致密性增加,抗氯离子腐蚀能力增强.     

热镀锌板钝化膜裂纹成因及控制研究

针对某冷轧厂钝化镀锌板耐盐雾腐蚀能力较差的问题,对钝化膜表面形貌及微观结构进行了研究,发现其表面存在不同类型的裂纹。通过对带钢进行不同张力下弹性应变模拟,合理控制带钢张力与钝化后烘干温度,消除了裂纹,镀锌板的耐蚀性显著提高。     

热镀锌板表面无机组分与有机硅烷复合钝化膜

以硅烷偶联剂KH560和KH602复配出有机硅烷钝化组分,再加入双氧水改性的TiOSO4和Na3VO4无机组分,配制出无机组分-有机硅烷复合钝化液。通过电化学Tafel极化曲线、交流阻抗谱(EIS)和中性盐雾试验,对比了未钝化镀锌板、添加和未添加无机组分钝化的镀锌板的耐蚀性;通过附着力测试,评价了两种钝化膜层的附着性能;通过扫描电子显微镜,对比了三种试样表面的微观形貌。结果表明:加入无机组分能有效改善钝化膜的耐蚀性,提高膜层表面结构的致密性,从而形成耐蚀性好、附着力强、表面均匀、结构致密的复合钝化膜。     

自润滑型无铬钝化膜微观组织及有限元分析设计

通过星点设计响应面法优化自润滑型无铬钝化液配方。采用辊涂法在热镀锌钢板表面制备自润滑型无铬钝化膜。使用3D表面形貌轮廓仪和扫描电镜研究了膜层的微观组织;引入支架与填充剂结构参数λ;利用有限元分析方法,分析模型摩擦过程中的温度场、应力场变化;选用薄膜热电偶和激光干涉仪验证有限元等效模型的适用性。结果表明,自润滑型无铬钝化膜为多孔结构且填充剂能改善膜层表面的粗糙度,λ=0.25时膜层的摩擦磨损性能最优。此外,有限元分析结果与实验结果有较好的吻合度,可为金属表面自润滑型多孔膜层的研究提供参考。     

混凝土溶液中氯离子对建筑用钢筋钝性的影响

研究了混凝土溶液中氯离子对建筑用钢筋钝性的影响。结果表明,在-0.2~0.2 V的电位区间内钢筋表面生成一种钝化膜,该钝化膜的施主浓度随氯离子浓度的升高而减小。钢筋表面产生的钝化膜深层施主浓度随预钝化电位浓度的升高而增加,而浅层施主浓度正好相反。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

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.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.