Date of Graduation


Document Type


Degree Type



Statler College of Engineering and Mineral Resources


Mechanical and Aerospace Engineering

Committee Chair

W. Scott Wayne.


The large polycyclic aromatic plates within coal tar pitches do not flow freely enough to organize into large anisotropic domains during pyrolytic carbonization. It was hypothesized that mechanical shear stress might accomplish that orientation. To test the hypothesis a reactor and stirring mechanism were designed and constructed to test crystalline formation behavior during carbonization. The work shows a unique method for manipulating the crystalline structure of coke. The coke was derived from a coal tar pitch with an initial softening point of 147°C. During the pyrolytic devolatilization of the pitch, a shearing stress was applied mechanically. The stress promoted oriented texture in the direction of the applied stress as observed by polarized light microscopy. Powder x-ray diffraction was performed on the green coke samples. The crystalline intensity value was determined by integration of the diffraction intensity for the 002 peak of the amorphous green coke. The crystallite width, Lc, was calculated and found to be within 12 and 19 A. The insulating nature of the coke affected the temperature control system, which altered the thermal treatment of the samples. The optical results proved that the mechanically induced stress affected the pore size, shape, and anisotropic domain size. The texture of the coke ranged from fine lenticular to fine ribbon.