Effects of Holding Time and Pressure of Hot-pressing on Sintering and Graphitization of Coke with B2O3 Addition

Abstract

Effects of holding time and pressure of hot-pressing were investigated on some properties of the coke compacts made by hot-pressing at 2000°C and 2200°C from a calcined pitch coke powder mixed with 10 wt% B2O3. The holding time was changed from 0 to 4 hr and the pressure from 70 to 400kg/cm2.Bulk density and mechanical strength of the compacts increased and also their graphitization measured from the interlayer spacing d (002) and the appearance of 112 diffraction proceeded with the increase of holding time up to 1 hr.Above 1 hr, however, they showed almost constant values. The hot-pressing pressure gave a remarkable effect on densification and strength of the compacts, but almost no effect on graphitization.The compact with the bulk density of 2.13 g/cm3, the bending strength of 490 kg/cm2 and the d (002) spacing of 3.360A was obtained under the condition of the pressure of 400 kg/cm2 at 2200°C. The hot-pressing temperature and pressure were known to be very important factors to prepare the dense and strong compact from the coke with B2O3 addition.