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251.
本文用自制的划痕试验机研究了影响Ni-P合金镀层结合力的因素,分析了划痕试验时锭层开裂、剥离的情况,观察了镀后加热温度、基体硬度等对划痕形貌的影响规律,并用B-W公式计算了试样的结合力。结果表明,镀后加热温度越高,镀层厚度越厚,基体硬度越高,结合力越大。 相似文献
252.
Y. -S. Choi J. -G. Kim Y. -S. Kim J. -Y. Huh 《International Journal of Automotive Technology》2008,9(5):625-631
This project evaluated the corrosion damage over a five-year period of organic coated steels in automotive chassis parts during
P/G and field tests using electrochemical impedance spectroscopy (EIS) in a 3.5 wt.% NaCl solution. EIS can provide both quantitative
kinetic and mechanistic information about the performance of organic coating/metal systems. The difference in coating performance
between the P/G and field test specimens was assessed in relation to the impedance parameters. In particular, it was found
that the coating resistance and charge transfer resistance could be used to estimate the difference in corrosion damage between
the P/G and field test specimens. The coating performance of the P/G and field test specimens was visually evaluated using
SEM. The mechanism of corrosion occurring in the P/G test was similar to that taking place in the field test. The field test
environment was about ten times as corrosive as the P/G environment in terms of the electrochemical impedance parameters and
surface analysis. 相似文献
253.
介绍了埋地燃气管道外防腐层老化状况评价标准,以沥青外防腐层为例,通过应用马尔可夫链理论,阐述了基于逆阵的外防腐层老化状况预测的方法,从而为确定整条管线外防腐层老化状况分布提供了理论依据。 相似文献
254.
Microstructure of hot-dip galvanized Zn-Al-Mg alloy coating 总被引:1,自引:0,他引:1
The microstructure of hot-dip galvanized Zn-11%Al-3%Mg-0.2%Si alloy coating was studied in this article. X-ray diffraction analysis revealed the coating is composed by Zn, Al and MgZn2 phase. Optical microscope (OM) and scanning electron microscope (SEM) observations showed the coating is occupied by snowflake-like dendrite, double hexagonal organization and eutectic. The coating backbone was the dendrite considered to be a phase of hexagonal close-packed (HCP) structure judging form its morphology according to the crystal growth way in the coating. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) researches on the dendrite suggested that an intermediate Zn-Al phase was formed at high temperature, then decomposed into a type of Zn-Al granular eutectoid after cooling down to room temperature, while the eutectoid Zn and Al had a certain crystallographic relationship. The coating solidification process and the grain crystal structure were discussed. 相似文献
255.
Four kinds of ZrC coatings with nearly the same thickness have been successfully prepared on graphite substrate by chemical vapor deposition (CVD) through controlling the ratio of inlet reacting gases. From backscattered electron images, it can be inferred that ZrCIII coating has the best tightness of all coatings. Meanwhile, line energy spectrum curve shows that zirconium and carbon elements distribute uniformly along the normal direction of the ZrCIII coating. As for varied microstructures, the coatings show different mechanical properties and residue stress. The strength and elastic modulus of ZrCIII coating were up to 89.57 and 1 192.5GPa, respectively. Those make it near the level of diamond. Value of residue tensile stress of ZrC+C composite coating was only 7.729MPa and that of ZrCIII coatings was 349.632 MPa. The strong combination of small-size grains in ZrCIII coating plays a decisive role to the best mechanical properties. However, strong misfit of lattice between ZrCIII coating and substrate can induce high residue stress. 相似文献
256.
陶瓷/金属梯度热障涂层动态设计软件的研制 总被引:4,自引:1,他引:3
结合热障涂层和功能梯度材料的概念,研究陶瓷/金属梯度热障涂层动态设计软件的结构与功能及其实现过程。通过具体的例子,对多层圆筒模型的温度场的解析解、差分解及有限元解的仿真结果进行了比较及分析。 相似文献
257.
徐全伟 《交通部上海船舶运输科学研究所学报》2000,23(2):144-148
涂装工艺是决定涂层质量的主要因素,本文根据设备现状和生产实践,对工件的表面处理,粉末涂料的选择,涂装生产工艺的制备等方面进行了一些要求,对涂层剥离的各种原因进行了分析,以期获得更为合理的工艺规范。 相似文献
258.
259.
该文主要从两种桥梁所采用的基材及养护上提出一些新的品种和新的养护措施,来提高桥梁的耐久性和使用寿命。这也是对当前提高新的经济增长点、扩大内需、增加投入、环保节能以获得长期效应的建议和措施。 相似文献
260.