THE EFFECT OF GREEN DENSITY AND THE ROLE OF MAGNESIUM-OXIDE ADDITIVE ON THE DENSIFICATION OF ALUMINA MEASURED BY SMALL-ANGLE NEUTRON-SCATTERING

Small-angle neutron scattering measurements were used to examine the effect of green density and the role of MgO additive on the evolution of the porous microstructure of alumina during intermediate- and final-stage sintering. It was found that the initial connectivity in the green state plays a dominant role in establishing the channel diameters during the intermediate stage of sintering, and contributes also to determining the onset density at which the final stage of sintering begins. The role of MgO as a sintering aid lies, at least in part, in prolonging the stability of intermediate-stage sintering such that the body achieves greater density before the transition to final-stage sintering after which isolated pores are formed.