共查询到20条相似文献,搜索用时 69 毫秒
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介绍了测定环氧富锌底漆不挥发分中金属锌含量的方法,探讨了影响实验结果的主要因素,并对现行富锌底漆标准规定的测定方法条件进行了一些调整,以便得到满意的实验结果。 相似文献
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Sujit S. Laddha Pandurang S. Salunkhe Deepashri D. Nage 《Journal of Failure Analysis and Prevention》2016,16(4):527-532
A variety of materials are used in the Oil & Gas industry ranging from carbon steel, stainless steel to nickel alloys, etc. including non-metallic materials as well. Amongst these, carbon steel is the industry favorite because of many of its desirable attributes like machinability, weldability, availability, and cost. Wide use of carbon steel in the industry is also due to the presence of required properties for the specific application. In spite of carbon steel’s wide uses, poor workmanship, improper heat treatment, or negligent manufacturing processes can reduce its service life and also can lead to unexpected failures. One such failure case involves carbon steel plate meant for construction of a tank that failed by cracking immediately after the welding operation. A detailed investigation was carried out by means of visual examination, metallographic and chemical analysis, SEM, and EDAX analysis. Microstructure revealed banded pearlitic structure along with a number of inclusions, a few of which were elongated. In conclusion, stresses due to weld joint restraint, elongated inclusions, and high transverse direction stresses after welding resulted in lamellar tearing which propagated in the linear direction along the weld line. 相似文献
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本文采用非等温DSC法对环氧树脂的固化动力学进行了研究。分别通过Kissinger方法和Ozawa方法得到了树脂固化反应的活化能,均值为53.65 kJ/mol,用Ozawa公式计算得到了反应级数为0.886。 相似文献
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R. K. Eby 《Journal of research of the National Institute of Standards and Technology》1964,(3):369-372
Electron microscopy, together with wide- and small-angle x-ray diffraction studies, indicates that copolymers of tetrafluorocthylene and hexafluoropropylene are lamellar. The lamellar development is extensive; the lamellae can be broad and extend for many microns. The perfluoromethyl groups are incorporated within the lamellae as point defects. 相似文献
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采用吸附-化学沉淀法合成了磷酸铵锌/埃洛石纳米管(ZAP/HNT)复合材料,并将ZAP/HNT和Exolit? OP 1230膨胀型阻燃剂一起用于阻燃环氧树脂(EP)。采用红外光谱(FT-IR)和扫描电子显微镜(SEM)对合成的ZAP/HNT及其环氧树脂复合物(EP/ZAP/HNT)进行了表征,ZAP/HNT中ZAP的粒径约为20~50 nm,表面的-OH与环氧基发生了作用,在EP中分散均匀。热分析(TG)表明,ZAP/HNT在加热过程中脱水、脱氨,600℃时总质量损失约11.34%。790℃时, EP/ZAP/HNT的残炭量为26%,具有良好的成炭性能。用微尺度燃烧量热法(MCC)和UL-94等方法分析了复合材料的阻燃性能,与EP相比,EP/ZAP/HNT(25%)的HRR下降幅度可达到58.82%。ZAP/HNT与OP 1230具有明显的协同阻燃性能。对炭渣用能谱仪(EDS)和SEM进行了分析,P、Al、Si、Zn主要分布在残渣外层,说明燃烧中阻燃剂在气体的作用下迁移到表面,形成由焦磷酸盐、碳、Al2Si2O 相似文献
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本文通过对直缺口两个层团厚度拉伸试样的扫描电镜原位拉伸实验、相应的断裂表面观察以及有限元计算研究了全层铸状TiAl基合金组织的裂纹扩展机理.研究表明:为了扩展主裂纹,外加载荷需要增加.外加载荷的增加一方面归功于试样表面观察到的主裂纹并没有穿透整个试样厚度,另一方面因为应力场由缺口控制,只有随着外加载荷的增加,扩展的裂纹尖端才保持一定的应力.当两个层团的位向使裂纹从沿层扩展过渡到穿层扩展时,裂纹扩展阻力才提高. 相似文献