ELECTRICAL EFFECT AND INFLUENCE FACTORS OF TOURMALINE

摘要

Tourmaline is a crystalline boron silicate mineral with special electrical and optical behaviors. In this study, electrical performances of crystalline tourmaline samples from various deposit sites in China were evaluated. The results show that the piezoelectric constants of tourmalines, in a fixed crystalline direction, depend on their mineral species and the specialty elements in the crystal. The piezoelectric constant of dravite is higher than that of elbaite. The variety of piezoelectricity is resulted from the element type in crystal structure. Dielectric properties tests show that tourmaline is a low dielectric constant material and the dielectric constant is from 4×10~(-12)pf/cm to 10×10~(-12)pf/cm. The dielectric constant along C axis is higher than that in any other directions. Under room temperature, pyroelectric property of a crystal is proportional to the dielectric properties, and negatively correlated to the ferric oxide ratio.