Semi-quantitative correlation between optical anisotropy and CTE of needle-like coke grains

Anisotropic development in 9 lumps of needle-like cokes produced in the tube bomb was quantitatively evaluated to correlate it to the CTE of the coke. Distribution of anisotropic units classified according to their size and shape is not enough for quantitative correlation. Since the isochromatic unit is recognized as a vector, its length or component to the CTE axis is measured. The average of the latter values was found to be linearly correlated to the CTE value as for all cokes examined except for one from Taching VR. The last coke showed a skin-core distribution of the vectors in the lump, while other cokes showed very homogeneous development of anisotropic textures.