Tungsten Copper Power Properties Test (1/2)

Tungsten copper powder properties itself will directly affect the final performance of tungsten copper products so that the test of tungsten copper powder raw material becomes vital. At present, laser particle size analysis, transmission electron microscope, differential scanning calorimetry are the main test methods, next we will introduce and analyze them by theory and working principle.

Laser particle size analyzer judges the size of particles by distribution (ie, scattering spectra) by the diffraction space or scattered light particles. The method combines Fraunhofer with Mie scattering theory, when a bunch of laser irradiation wavelength λ in the small spherical particles of a certain size, the beam encounters a barrier, diffraction and scattering phenomenon will occur. Generally, when the particle size is less than 10λ, the main phenomenon is scattering, while the particle size is greater than or equal to 10λ, the main phenomenon is diffraction.

The most widely used laser particle size analyzer currently usually uses 500-700nm wavelength laser as a light source, which test particles size above 5μm is relatively accurate. For particle size of less than 5μm by Mie theory is mathematically corrected, which means that for the sub-micron or nano-scale particles have a certain measure of error. In addition, theoretical model of laser particle size analysis is based on spherical particles and mono-disperse condition, and thus for the particle shape and particle size distribution will have a greater impact on the final results of particle size analysis. The more irregular shape of particle, the wider particle size distribution, the final error will be greater. For tungsten copper composite powders, the water as a dispersant and add ethanol for grinding, after 30 minutes of ultrasonic cleaning in distilled water dispersion of particle size analysis.