Effect of Hot-pressing Temperature on Sintering and Graphitization of Coke with B2O3 Addition

Abstract

Effect of hot-pressing temperature was investigated on some properties of polycrystalline coke compacts made from calcined pitch coke powder with 10% B2O3 addition at various temperatures from 1200 to 2200°C under a pressure of 200kg/cm2.Bulk density was almost constant as 1.6g/cm3 up to 1800°C, and increased rapidly to about 2.0 g/cc above 2000°C.Mechanical strength once decreased at temperature range from 1600 to 1800°C, and it increased again above 2000°C.Graphitization proceeded remarkably above 2000°C.B4C was formed at 1600°C and amount of B4C decreased with increase of temperature.The hot-pressed compacts could be classified into three types.The first is the one made below 1400°C in which coke particles adhered each other with B203 glass phase, the second is the one made between 1600 and 1800°C which consist of the mixture of coke particle and small amount of B4C exist independently, and the last is the one made above 2000°C of which boron is considered to give strong influence for sintering and graphitization of coke by its diffusion into coke structure.