Property evaluation on the spontaneous polarity for nanopowders.

For the tourmaline fine powders, in view of their low polarized charge density and easily occurred neutralization, a new evaluation model on the spontaneous polarity was proposed. By adjusting the temperature and applying electric field, the polarized charge could be measured. On this basis, a portable evaluation device was designed and assembled into four parts: Voltage Input Unit, Temperature Control Unit, Sample Loading Unit, and Charge Detection Unit.

Effects of particle size on far infrared emission properties of tourmaline superfine powders.

Tourmaline superfine powders with different particle sizes were prepared by grinding, superfine ball milling, and high-speed centrifugation. The powders were characterized by scanning electron microscopy, X-ray diffraction, dynamic contact angle meter and tensiometry, and Fourier transform infrared spectrometry. The results show that tourmaline powders exhibit improved far infrared emission properties as the particle size decreases.