Effects of Particle Size on Far Infrared Emission Properties of Tourmaline Superfine Powders

摘要

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. The increased surface free energy and proportion of the polar component are considered to play an important role for their properties. The spontaneous polarization is increased, and the dipole moment of tourmaline is stimulated to a high energy level more easily for the chemical bond vibration, so that the energy is apt to emit by transition. In the range of 2000-500 cm~(-1), the emissivity values of the samples with D_(50) size of 2.67 μm and 0.2 μm are 0.973 and 0.991, respectively.