Analysis of porous structure and permeability samples of graphite-containing refractory

Laboratory samples of graphite-containing refractories (crucible and muffle masses) were fabricated and the effects of their starting composition and heat-treatment conditions on apparent (p(a)) and pycnometric (real, p(r)) densities, open porosity (P-o) gas permeability (K-g), specific surface area (S-w), and pore specific volume (V)-radius size distribution were investigated. It has been found that the optimal pore structure (minimum values of P-o, V, K-g, S-w) for the crucible masses is formed at the heat-treatment temperatures (HTT) of 1350-1400 degreesC, and for the muffle masses at 1100 degreesC. The increase in HTT up to 1600 degreesC in all cases results in the increase of P-o, V, and K-g, and the decrease of the material strength.