Nano-tungsten powder was prepared on the basis of an industrialized production technique, using WO2.72 as the raw materials. The phase, composition, morphology, thermal stability, special surface area and pore structure of the samples were characterized by XRD, EDS, SEM, FESEM, DTA-TG, BET and pore Size Analyzer. The results show that high-quality nano-tungsten powder can be produced by reducing the hydrogen reduction temperature, slowing down the pushing boat speed, reducing the boat charging capacity and increasing hydrogen flow rate.

Nanocrystalline tungsten carbide(nano-WC) powder was prepared on the basis of the industrialized production equipment.Methods of X-ray diffraction,specific surface area,FESEM,TEM,and laser particle analyzer of dynamic light scattering were applied to test the phase,particle size and its distribution of nano-WC powder.Discussion was made for the testing principle.The results indicate the average particle size of nano-WC is 90 nm and most of the particles are spherical shape,but few are the shape of the polygon.In order to more accurately measure particle size of nano-WC powder,the sample should have good dispersion to avoid aggregation.The shape of nano-WC powder also have important influence on measurement of particle analyzer of dynamic light scattering.

Nano-WC powders were prepared through fast carbonization for 15 min at 1 050℃using nanotungsten powders and carbon black as raw materials by industrial production technology.The phase,composition, morphology and particle size of nano-WC powders were analyzed by means of XRD,EDS,SEM and FESEM.The results show that the purity of the nano-WC powders was very high.The powders had a small amount of W_2C and free carbon.The particles uniformly distributed,which were spherical,plate and polygonal.And the average particle size was 68.9 nm.

Nano-W powder was produced by industrialized production technology, and the heat treatment of samples was carried out at different temperature. The morphology, phase, content and special surface area, and pore structure of the samples were characterized using SEM, XRD, EDS and automated surface area and pore size analyzer respectively. The lattice changes of the samples after heated treatment were judged by calculating the change rate of lattice, and the growth mechanism of grain and the change of pore structure were explained by measuring its grain size and pore volume. The results indicate that the lattices of nano-W powder after heat treatment have changed into expansion from contraction. With temperature increasing, the specific surface area and pore size decreases, and particle size increases. The grain growth is very rapid at 1200 ℃, and its growth mechanism is explained according to grain boundary migration.

Nanocrystalline tungsten carbide(nano-WC) powder is prepared on the basis of the industrialized production equipment.Methods of X-ray diffraction,specific surface area,SEM,FESEM and TEM are applied to test the phase,particle size and its distribution of nano-WC powder.The results indicate the average particle size of nano-WC is about 90nm and most of the particles are spherical shape.Nano-WC powder is annealed at different temperatures for different time.The grain coarsening mechanism is studied and proved to be according with the classic LSW theory. Furthermore,temperature is an important factor to affect the grain growth of nano-WC and the grain size increases with the high temperature.

Nanocrystalline tungsten carbide(nano-WC) powder was prepared on the basis of the industrialized production equipment and were annealed at various temperature.Methods of X-ray diffraction,FSEM,TEM,specific surface area,and particle analyzer of dynamic light scattering were applied to test the phase,particle size and its distribution of nano-WC powder.The results indicated temperature was a important factor to affect the grain growth of nano-WC.The grain size increased with the high temperature.The DSC curves of nano-WC powders were measured at difierent heating rates and the activation energy for grain growth of nano-WC was calculated.Then,these experiment phenomena were analyzed and discussed.

Nano-W powder with various grain sizes are successfully produced on the basis of industrialized production technology.The content,morphology and phase of the samples are characterized by using EDS,SEM and XRD,and the lattice parameters and cell volume are worked out.The results indicate that nano-W powder have bcc crystal structure,the shrinkage of lattice has taken place.With the decrease of the grain sizes,the shrinkage rate of the lattice parameters and cell volume increases and the lattice distortion rate is inverse proportional linear relationship to the grain sizes.