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71.
以黄海海域为研究区,通过动电位极化曲线法获取了出海实测的EH36钢材在2017年8月及12月黄海43个站位的初期腐蚀速率的数据,并以地统计学方法对数据进行分析,探索研究区内EH36钢材的腐蚀速率的空间分布及其变异特征,绘制初期腐蚀速率预测图。结果表明:初期腐蚀速率的分布状况在夏季、冬季呈现不同的特征,夏季分布呈现近岸低、远岸高,中心高、周围低的特点,冬季分布呈现中心及东南部分低、周围高的特征。同时,统计分析表明, EH36钢在黄海的平均初期腐蚀速率,夏季为0.11 mm/a,冬季为0.25 mm/a,并且在夏季和冬季里, EH36钢在黄海初期腐蚀速率分布的空间变异特征明显,空间自相关性强,其中8月的块金值/基台值为0.062,12月的块金值/基台值为0.138,变程在100 km左右。 相似文献
72.
用电化学方法测量了Mg_2B_2O_5晶须增强AZ91D镁基复合材料在3.5%NaCl溶液中的开路电位、动电位极化曲线和交流阻抗,研究了晶须体积分数对镁合金基体耐腐蚀性能的影响,并利用SEM和XRD表征了腐蚀后复合材料表面的微观形貌和相组成。结果表明,随着Mg_2B_2O_5晶须体积分数的增加,AZ91D镁基复合材料的耐腐蚀性逐渐提高。当硼酸镁晶须的体积分数为35%时,材料的自腐蚀电位提高0.2V以上,自腐蚀流密度降低了1个数量级;SEM测试表明,复合材料表面生成了一层晶须增韧的腐蚀钝化膜,对基体起到保护作用。 相似文献
73.
The features of fracturing and dissolving of Yunnan marble in distilled water near the critical temperature have been studied
experimentally. The results indicate that the mechanical parameters of the samples (fracture strength, Young’s Modulus, shear
fracture energy and fracture toughness) drop with the temperature of the environment water, near the critical temperature
(380°C), these parameters have sudden changes (drop), then keep stable values roughly. The contents of some chemical materials
in the water, PH value and conductivity at every experiment temperature have been analysed and measured. At 380°C, there all
exist sudden changes. According to the results, it is pointed out that the sudden changes are related to strong stress corrosion
of water near its critical temperature to the rock and the exist and its migration of the water solution near the critical
temperature in the crust have important significance to the earthquake source process, the formation cause of the low-focal
depth earthquakes in the crust.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,14, 156–163, 1992.
This work was sponsored by the Chinese Joint Seismological Science Foundation. 相似文献
74.
Yozo Kudo Osam Sano Naokuni Murashige Yoshiaki Mizuta Koji Nakagawa 《Pure and Applied Geophysics》1992,138(4):641-656
The double-torsion test using Aji granite was carried out to investigate the interaction between stress-induced crack path and mineral grains. Crack velocities were controlled at range 10–7 m/s to 10–1 m/s. After the stressed specimens were dyed, we checked the crack path by thin section analysis, using an optical microscope. The stress-induced crack path was divided into two types, transgranular and intergranular cracks, and each path was subdivided with respect to mineral grains. In spite of the extensive range of crack velocities, the ratios between the transgranular and intergranular crack lengths did not change. The crack paths were all jagged, and often showed detour around the grain boundary when faced with obstacles like hard grains or preexisting cracks. That is to say, quartz grain played an important role as an obstacle. Feldspar grain could change the crack path because of its cleavage plane. Biolite grain had a serious effect on the path even if its constitution ratio is very small. Fractal dimensions of the crack paths were calculated by three methods, as indicators of surface roughness. The fractal dimensions were shown in a slight trend with the change of crack velocity. This trend can be explained from the point of limited cracking rate in stress corrosion. 相似文献
75.
钻井液的性质及性能参数对于南极科学钻探有着重要的影响。钻井液除了必须要具备合适的粘度和密度,以满足冷却钻头、平衡孔壁压力、携带冰屑、清洁孔底的要求外,钻井液的性质如导电性、导热性及其腐蚀性对于保证钻具的正常工作、输送孔内信息也有着重要的影响。根据目前已经在南极使用的钻井液类型,分别对6种介质(国产硅油-3cst、KF96硅油-2cst、丁酸乙酯、丁酸丁酯、丁酸戊酯、丙酸丙酯)在不同温度下的电导率、导热系数和对密封件的腐蚀性进行了试验测试,选出了适合南极应用的钻井液类型及在钻具中使用的密封件材质,可供极地钻探选择钻井液类型及钻具设计提供重要的参考。 相似文献
76.
78.
- Offshore platforms are always subjected to wave action which is random variable amplitude cyclic loading. In order to simulate the stressing condition at the 'hot spot' of the tubular joints and the marine environment, random variable amplitude fatigue tests have been carried out on welded plate joints in sea water. The tests have been conducted under the conditions of loading frequency of 0.2 Hz, stress ratio of -1, seawater temperature of about 20℃ and cathodic protection with the potential about -850 mV, SCE. The test results have been compared with the seawater corrosion fatigue life under constant amplitude loading. Miner's linear cumulative damage summation rule has been used to predict the corrosion fatigue life under variable amplitude loading. The predicted life is in good agreement with the test data. 相似文献
79.
LF4铝合金在海水中的腐蚀性能研究 总被引:1,自引:0,他引:1
对艇用铝材LF4及其它多种管系金属材料进行静态和动态条件下的自然电位、自然腐蚀率、电化学性能、电偶腐蚀行为等进行多方面的腐蚀试验,得出这些材料在静态和动态海水中的腐蚀性能指标以及变化规律。随着海水流速的增加,LF4铝合金耐蚀性迅速降低。LF4在天然海水中有钝化的趋势,但是钝化膜不完整易破坏。在与其它常用管系金属材料组成的电偶对中,LF4均作为阳极受到加速腐蚀。 相似文献
80.
1. IntroductionConcrete is widely used for nearshore and offshore marine structures and bridges (Song et al.,2000; Wang and Song, 2004). Experience has shown that the durability of marine concrete structuresis generally good; however, some cases of serious deterioration also exist due to the lack of durability(Metha and Gerwick, 1982). Under marine conditions, concrete, especially concrete in the splashand tidal zone, is attacked, resulting in corrosion of reinforcing bars. Corrosion of rein… 相似文献