By conducting experiments under pressures on the matrix of a single molten carbonate fuel cell (MCFC), as well as by performing comparative sintering experiments with and without the molten carbonate, changes in the maximum pore diameter, pore-size distribution, crystalline phase, Brunauer-Emmett-Teller (BET) surface area and surface configuration were measured. The parameters of the effectiveness of the gas barrier (Delta P > 0.1 MPa) and the porosity (40% < 8 < 70%) were taken as lifetime criteria for the matrix. By using regression equations based on the experimental results, the matrix was estimated by two aspects: maximum pore diameter and porosity for commercial requirements. Meanwhile, changes in the maximum pore diameter, pore-size distribution and porosity for estimating the sintering behavior were presented and explained theoretically. Rearrangements, slips and dissolutions of the alpha-lithium aluminate (alpha-LiAlO2) particles were observed in the matrices, which promote the alteration of the pore diameter and porosity during the sintering processes. (c) 2006 Published by Elsevier B.V.