Fig. 9From: Nano-materials enhanced protectants for natural stone surfacesSchematic diagram of the water vapor permeability experiment (a), and relative mass of the cups lidded by stone slices (b–d). The nano-power concentrations used in the experiments are 1.5 mg/mL Al2O3 and 0.1 mg/mL SiO2 for Marble, 1.5 mg/mL Al2O3 and 1.0 mg/mL SiO2 for Qingshi, and 0.5 mg/mL Al2O3 and 1.0 mg/mL SiO2 for Hedishi, respectivelyBack to article page