铸铁中石墨形态和石墨结构的研究

采用扫描电子显微镜，通过深腐蚀和热腐蚀方法，研究了铸铁中各种典型石墨（片状石墨、蠕虫状石墨和球状石墨）的立体形貌和内部结构特征。对于片状石墨来说，A、C、D型均属同一种石墨形态，它们都是由分枝而又互相联系的石墨片组成，它们主要是沿着1010]方向长大。对于球状石墨来说，用纯镁、纯钇、纯铈和工业球化剂均能得到球状石墨。热腐蚀结果表明，石墨球呈年轮状结构，它是由许多角锥体组成的多面体。这说明，石墨球的外表是（0001）面，石墨球的长大是由中心沿0001]方向进行。蠕虫状石墨是介于片状和球状石墨之间的中间石墨形态。它的长大方式也介于片状和球状石墨之间。就石墨片的互相联系和彼此分枝情况来看，它与片状石墨相似，但就每个石墨片局部的长大方式来看，它又与球状石墨有某种程度的相似，即沿着0001]方向长大较充分。

The Investigation of Graphite Morphology and Structure in Cast Iron

The characteristic of the morphology and structure of the typical graphite (flake, spheroidal vermicular) in cast iron have been investigated with scanning electron microscopy (SEM). The observation on the specimens which had been treated with deep etching and thermal oxidation etching was carried out and the results were obtained as follows;1.The various classes of the flake graphite (Classes-4, B, C, D) were consisted of flakes that were branchecd and interconnected. So that they belong to the same type of graphite Growth of them occurred primarily on fhe 1010] direction, and was inhibited on the 0001] direction, it follows that fhe flake graphite was formed.2.The spheroidal graphite may be obtained in cast iron treated with commercially pure magnesium, yttrium or cerium as well as industrially nodulizing agents. The formations of the spheroidal graphite in cast iron treated with one of them was different. The surface of the spheroidal graphite obtained with magnesium is more smooth and rounded than that with yttrium and cerium. And the surface of the spheroidal graphite obtained with the industrially nodulizing agents is intermediated between the two kinds of form of the graphite.It was observed in the thermal oxidation etching specimen that there are annualring structure in the spheroidal graphite. It was shown that the surface of the spheroidal graphite was (0001) plane of the graphit crystalline. And its growth was carried on from the center of it, and was along to the 00001] direction.3. The vermicular graphite was a intermediate morphology between the flake and spheroidal They connected each other in same eutectic cello The mode of growth of the vermicular graphite was intermediate between the flake and spheroidal also.