共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
3.
4.
锌离子是锌系磷化液中必须的成份,含量太低(低于5g/L),磷化膜形成困难,但含量太高时,可形成粗大的结晶、更大的厚度,对涂装又是不利的。为改善磷化膜性能,在锌系磷化液中通常还要加入Ni~(2+)、Mn~(2+)、Co~(2+)等。本文就Zn~(2+)、Co~(2+)含量对磷化膜的形成及其性能(厚度、结晶尺寸及状态和防护性)作一讨论。 1 试验方法 (1)Zn~(2+)、Co~(2+)对磷化过程的影响是采用测钢试片(作阴极,阳极为不锈钢片)电位变化进行考察的。 相似文献
5.
长期处于户外的输电杆塔容易遭受锈蚀而受损,传统的涂料涂覆处理无法起到同时除锈和防腐的作用,因此亟须探索一种适合输电杆塔的绿色磷化处理工艺。基于电化学与响应面分析法,以磷酸与氧化锌为基础磷化液,研究植酸、复合钝化剂BM1、硝酸锰三种促进剂的浓度对锌系磷化膜成膜质量的影响,以硫酸铜点滴时间评判其耐蚀性。采用扫描电子显微镜观察添加不同促进剂的磷化液所形成磷化膜的表面形貌。通过响应面分析法对磷化液的成膜耐腐蚀效果进行优化,得到硫酸铜点滴时间的二次响应方程。各因素影响次序为硝酸锌>复合钝化剂(BM1)>植酸>硝酸锰,通过优化获得硫酸铜点滴时间为101 s的磷化液配方,即氧化锌15 g/L、磷酸100 g/L、复合钝化剂BM1 1.7 g/L、植酸11.7 mL/L、硝酸锌52.4 g/L、硝酸锰5.9 g/L、OP-10乳化剂适量。通过响应面优化参数得到的磷化液配方在具有除锈功能的同时能有效提高Q235低碳钢的耐腐蚀性能,可为磷化液新配方的性能预测和浓度优化提供方法与理论指导。 相似文献
6.
目的优化镁合金锌系磷酸盐化学转化膜的制备工艺。方法制备锌系磷酸盐化学转化膜,采用点滴实验、电化学测试对化学转化膜进行耐蚀性评价,并通过激光共聚焦显微镜、扫描电子显微镜(SEM)和X射线衍射仪(XRD)对膜层进行表征,研究主盐、温度和添加剂对镁合金锌系磷酸盐化学转化膜的影响。结果转化溶液中氧化锌、磷酸、氟化钠、酒石酸钠的浓度对转化膜的耐蚀性和膜厚具有较大影响,在一定浓度范围内,转化膜的耐蚀性随浓度的增加而增大。转化膜耐蚀性随温度的升高先增加后下降,50℃时点滴时间达到59 s,膜层相对致密,缝隙较小。选取的添加剂中,EDTA能明显提高膜层的耐蚀性,膜层均匀致密,加入0.3 g/L EDTA的转化膜的腐蚀电位比未加添加剂的转化膜正移0.05 V,点滴时间提高到68 s。镁合金锌系磷酸盐转化膜主要成分为Zn_3(PO_4)_2+Zn_2Mg(PO_4)_2+AlPO_4+Al_(12)Mg_(17)。转化膜的电化学阻抗半径大,自腐蚀电流密度低(2.594×10~(-6) A/cm~2),腐蚀电位正移较明显,耐蚀性更好。转化膜粗糙度小(2.396μm),平整光滑。结论镁合金锌系磷酸盐转化最优配方及工艺为:氧化锌2.0 g/L,磷酸12 g/L,氟化钠1.0 g/L,酒石酸钠4.0 g/L,EDTA 0.3 g/L,转化温度50℃,转化时间20 min。转化溶液加入EDTA后,能够明显提高转化膜的耐蚀性。 相似文献
7.
邝钜炽 《腐蚀科学与防护技术》2006,18(2):126-128
探讨了在硝酸盐-锌系磷化过程中稀土化合物、溶液酸碱度、时间对磷化膜外观、膜重和耐蚀性的影响.结果表明,把少量稀土化合物(REC)添加到磷化液中可显著提高磷化膜的耐蚀性和磷化速度,其较佳的投加量为30 mg/L~55 mg/L.
相似文献
8.
9.
提高耐蚀性的锌系磷化工艺探讨 总被引:4,自引:0,他引:4
用正交实验确定了一组锌系磷化液的最佳工艺参数.并着重讨论了在磷化液中加入促进剂、催化剂以及NO_2~-、金属离子,使得金属磷化膜的耐蚀性质得以提高.CuSO_4点滴试验时间可达200s以上. 相似文献
10.
冷轧A3钢薄板的稀土复合锌系低温磷化 总被引:1,自引:1,他引:0
为配制出成膜质量更佳的涂装用磷化液,从锌系磷化膜形成机理出发,分析了改善其低温成膜效果的可能途径;通过高效促进剂和磷化工艺参数的优选,开发出一种实用性强的钢铁工件涂漆前处理--含稀土复合促进剂的低温锌系磷化新工艺.研究表明:家电外壳广泛采用的冷轧A3钢薄板经此LZP快速磷化液处理后,所得防锈涂装底层实用效果良好.在含1.0~2.0g/L 稀土促进剂的磷化液中,A3钢薄板经40℃、3~4min喷淋处理后可获得厚约3μm的磷化膜,其结晶细小致密、与基体结合力强、抗蚀性好.磷化后经在线涂漆,对应漆膜抗冲击性、耐蚀性和附着性能良好. 相似文献
11.
Deng-Kui Zhang Guo-Qing Wang Ai-Ping Wu Ji-Guo Shan Yue Zhao Tian-Yi Zhao Dan-Yang Meng Jian-Ling Song Zhong-Ping Zhang 《金属学报(英文版)》2019,32(6):684-694
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. 相似文献
12.
After nearly two years'tense construction the first phase of industrialized base of Shenyang Research Institute of Foundry 《中国铸造》2008,5(1):63-64
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. 相似文献
13.
Z. Sun S.L. Zheng Y. Zhang 《金属学报(英文版)》2007,20(3):187-192
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. 相似文献
14.
R. González-Martínez 《金属学报(英文版)》2007,20(4):235-240
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. 相似文献
15.
The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C). 相似文献
16.
This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before. 相似文献
17.
Chao Yang He-Fei Huang Massey de los Reyes Long Yan Xing-Tai Zhou Tian Xia De-Liang Zhang 《金属学报(英文版)》2015,28(7):809
Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties. 相似文献
18.
Lei Li Bo Xu Wei-Ping Tong Hui Zhang Chun-Yan Ban Li-Zi He Zhi-Hao Zhao Yu-Bo Zuo Qing-Feng Zhu Jian-Zhong Cui 《金属学报(英文版)》2015,28(6):725
A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed. 相似文献
19.
The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel. 相似文献
20.
综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。 相似文献