Highly anisotropic metallized wood obtained by filling basswood channels with low-melting-point Sn-Bi alloy

Basswood and Sn-Bi alloy have several complementary properties—the former has a low density, no electromagnetic shielding, poor thermal and electrical conductivity, and low impact toughness, while the latter has exactly the opposite properties. Combining the natural porous structure of basswood with a low-melting Sn-Bi alloy can produce a composite with the merits of both materials. In this study, basswood was pretreated with 5 % ammonia water, and then the Sn-Bi alloy was filled into the cell lumens and vessels without lignin at 138 ℃ and 3000 Pa. After metallization, the density of the basswood increased from 0.5 g·cm−3 to 3.0 g·cm−3, reaching six times its initial value, which also doubled the impact toughness. The total electromagnetic interference shielding effectiveness of the metallized basswood obtained using different filling methods ranged from 45 dB to 70 dB. Heat-transfer simulations and circuit experiments were carried out to investigate the thermal and electrical conductivity of this composite, and the results demonstrated its anisotropic conductivity. These properties showed that the metallized basswood could be used as a functional or structural material in different fields.