Abstract:     As for similar research had not been reported about the discussion of the soluble salt NaCl, NaNO3 and their composite in effloresces pottery, the analysis of the properties such as surface tension, concentration and equilibrium crystalline phase of salt solution and their composite were studied, as well as the destructive process and effect of the salt for the pottery was discussed with the test methods of digital microscope and automatic mercury porosimetry etc. The results indicated that the ratio of dissolution and crystallization of composite salt NaCl/NaNO3 was accelerated in pottery samples and the damage effect was serious on the condition of the ability of water absorption and desorption in composite salt NaCl/NaNO3 was much higher than that in single NaCl or NaNO3.
The mushroom shaped salt crust in composite salt was wrapped in the pottery particles tightly and the area was gradually decreased under the relative humidity cycles, the micro-cracks was expanded expressed in the continuous salt crust area was decreased and the discontinuous area was increased, which showed as the average pore size of the pottery sample was decreased and the contents of microporous was increased. In all, the process and the action of composite salt NaCl/NaNO3 or the pottery samples were studied for the sake of scientific research in next protection.