【作者】 兰孝文；

【导师】 董俊慧；

【作者基本信息】 内蒙古工业大学 ， 材料学， 2009， 硕士

【摘要】 内蒙古自治区天然碱储量丰富,利用天然碱制烧碱工业是重要的基础工业,但在天然碱制烧碱工业中存在着设备的严重腐蚀问题,不仅消耗了大量的金属材料,而且增加了生产的成本,制约了企业的发展。因此,研制、开发耐碱腐蚀新型材料具有重要的实际意义。本文设计了加稀土低、中合金铸铁材料,研究了其在天然碱苛化烧碱液中的腐蚀行为,通过静态失重法测定了两类合金铸铁材料的腐蚀速度,并对其进行耐蚀性评价。借助光学显微镜观察石墨形态并分析金相组织,并结合X射线衍射,确定合金铸铁的各相组成物类型。利用扫描电镜观察腐蚀试样表面形貌特征,分析微区成分,探讨了加稀土合金铸铁在天然碱苛化烧碱液中的耐腐蚀机理。结果表明:随着稀土含量的逐渐增加,加稀土低、中合金铸铁的基体组织得到细化,石墨形态发生了变化。但是稀土含量超过一定量时,白口组织倾向严重。在不同腐蚀条件下,加稀土低合金铸铁的RD3(0.06%RE)试样和加稀土中合金铸铁的RZ3(0.05%RE)试样表现出较好的耐碱腐蚀性能。其原因为在RD3和RZ3试样表面形成较致密的腐蚀产物,阻隔了碱液与材料的接触,对基体起到了保护作用。更多还原

【Abstract】 The reserves of natural base is abundant in Inner Mongolia, the industry which uses natural base to make sodium hydroxide is an important industry, but the corrosion problem of equipments is very serious in the process of making sodium hydroxide, not only lots of metal materials are consumed, but also the cost of production is increased, which restricts the development of basic industry. So, it is very important to develop and exploit new types of materials of corrosion resistance.In this paper, two types of alloy cast iron were designed, including low alloy cast iron of rare-earth addition and medium alloy cast iron of rare-earth addition. The corrosion behavior in the caustic soda was researched, the corrosion rate was tested by the methods of static weight-loss and the corrosion grade was evaluated. The graphite form was observed by an optical microscope, the metallurgical structure was analyzed and the matrix structure was defined by an x-ray diffraction instrument. The corrosion products were observed and the content of elements was analyzed by the SEM and the corrosion resistance mechanism of the alloy cast iron of rare-earth addition in the caustic soda was discussed.The results showed that the matrix structure of these two types of alloy cast iron was refined and the graphite form was changed with the increase of rare-earth content. At the same time, when the rare-earth content was beyond some content, the chilling tendency was serious. The caustic corrosion resistance performance of low alloy cast iron of rare-earth addition with 0.06%RE and medium alloy cast iron of rare-earth addition with 0.05%RE is better under the different corrosion conditions. Becaruse more compact corrosion products were formed on the surface of test specimen RD3 and RZ3, which seperated the materials and alkali liquor and protected the matrix.更多还原