Simulation of thermal diffusivity of Al/NaCl powder compacts in producing Al foams by the sintering and dissolution process

In the sintering and dissolution process for manufacturing Al foams, effective sintering is crucial to achieve a strong bonding between the Al particles. In order to predict the time needed for the sintering temperature to be reached throughout an Al/NaCl compact, it is necessary to characterize its thermal diffusivity. This paper determines the thermal diffusivities of a series of Al/NaCl compacts by measuring their temperature profiles during heating and comparing them with computer simulations using Matlab. The thermal diffusivities are found to be in the region of 3 × 10−7 m2/s and increase approximately linearly with increasing the weight fraction of Al in the compacts. They are much lower than those of the Al and NaCl, due to the existence of low-thermal-conductivity air in the compacts. The time needed for temperature homogenization is mainly determined by the geometry and size of the compact. The effect of Al weight fraction is less significant in comparison.