The densification mechanism of an Fe-based alloy powder containing tiny oxide particles under the synergic multi-field effect of spark plasma sintering （SPS） was investigated. Metallographic microscopy and scanning ...The densification mechanism of an Fe-based alloy powder containing tiny oxide particles under the synergic multi-field effect of spark plasma sintering （SPS） was investigated. Metallographic microscopy and scanning electron microscopy were used to observe the morphology of samples sintered at different temperatures, and the temperature dislribution in an individual spherical powder particle during sintering was calculated in consideration of the influence of plasma, which was qualified and quantified through the analysis of the U-Icurve. The plasma was observed to play a substantial role in activating and heating the samples at the very early stage of sintering, whereas the joule-heat effect played a dominant role during sintering. Moreover, the plasma also facilitated the diffusion and migration of materials for neck formation.展开更多
In this study,the effects of powder mixed method,sintering temperature,and the additive amount of the conductive phase on the dielectric loss tangent and permittivity constant of AlN/Mo composite ceramics were investi...In this study,the effects of powder mixed method,sintering temperature,and the additive amount of the conductive phase on the dielectric loss tangent and permittivity constant of AlN/Mo composite ceramics were investigated.All the ceramic samples were prepared by spark plasma sintering(SPS).AlN composite ceramics with additional 10 vol%Mo sintered at 1400℃holding for 5 min exhibit the best dielectric loss tangent,which is greater than 0.23.AlN/Mo ceramics with additional 20 vol%Mo become conductive,with the resistivity of 0.05–0.06Ω·m.High-energy ball milling is better than magnetic stirring powder mixing method.In addition,the additive Mo and lower sintering temperature lead to a better property with the increase in the electromagnetic wave frequency range of 1×10^(3)–1×10^(6)Hz.展开更多
基金financially supported by the Major State Basic Research Development Program of China (Nos. 2007CB209801 and 2011CB610400)
文摘The densification mechanism of an Fe-based alloy powder containing tiny oxide particles under the synergic multi-field effect of spark plasma sintering （SPS） was investigated. Metallographic microscopy and scanning electron microscopy were used to observe the morphology of samples sintered at different temperatures, and the temperature dislribution in an individual spherical powder particle during sintering was calculated in consideration of the influence of plasma, which was qualified and quantified through the analysis of the U-Icurve. The plasma was observed to play a substantial role in activating and heating the samples at the very early stage of sintering, whereas the joule-heat effect played a dominant role during sintering. Moreover, the plasma also facilitated the diffusion and migration of materials for neck formation.
基金financially supported by the International Cooperation Project between China and Russia (No. 2010DFR50360)
文摘In this study,the effects of powder mixed method,sintering temperature,and the additive amount of the conductive phase on the dielectric loss tangent and permittivity constant of AlN/Mo composite ceramics were investigated.All the ceramic samples were prepared by spark plasma sintering(SPS).AlN composite ceramics with additional 10 vol%Mo sintered at 1400℃holding for 5 min exhibit the best dielectric loss tangent,which is greater than 0.23.AlN/Mo ceramics with additional 20 vol%Mo become conductive,with the resistivity of 0.05–0.06Ω·m.High-energy ball milling is better than magnetic stirring powder mixing method.In addition,the additive Mo and lower sintering temperature lead to a better property with the increase in the electromagnetic wave frequency range of 1×10^(3)–1×10^(6)Hz.
