Thermoelectric And Mechanical Properties Of Homogeneous Nano-composites Prepared By High Pressure Sintering

Thermoelectric materials are one kind of functional materials which can transform heat and electricity to each other,and skutterudite material is one of the thermoelectric materials,which has excellent electrical properties,including high carrier mobility and fine Seebeck coefficient.Although its thermal conductivity is higher than that of other thermoelectric materials,it can be reduced by doping,filling and nano-combination due to its special crystal structure.For these reason,at present,skutterudite material is one of the most development thermoelectric materials in the thermoelectric family.In addition,thermoelectric materials will be affected by the effect of thermal stress in the process of service,so the mechanical properties of thermoelectric materials are becoming more and more attentioned.In this paper,first,the micro compound Co₄Sb_11.5Te_0.5 was synthesized by solid phase reaction.Then,the nano-compound was gotten by high-energy boll-milling technique.At last,the homogeneous nanocomposite compounds Co₄Sb_11.5Te_0.5+x wt%nano-Co₄Sb_11.5Te_0.5?x=0,10,20,40?were obtained by high pressure sintering.In addition,the preparation process,organization structure,thermoelectric and mechanical properties of homogeneous nanocomposite compound Co₄Sb_11.5Te_0.5 were studied.The results of research indicated:1)The homogeneity nanocomposites prepared by high pressure sintering,not only have a pure phase,high density,and the nanoparticles grain of the material didn't grow up after sintering.2)All materials prepared by high pressure sintering,although have a poor electronic property at low temperature,the electronic property become better at high temperature.On the other hand,the grains of the materials were prevented to grow up because of the high pressure sintering,makes the homogeneous nano-composite compounds reflect low thermal conductivity.The thermoelectric properties of materials remarkably increased with the nanoparticle content,and at 800K,the figure of merit of the material achieved maximum 1.37 when the nanoparticle content equal to 40%,improved 58%relative to based material.3)At room temperature,with the increasing of nanoparticle content,the bending modulus and the compression modulus of the materials changed little.But the bending strength and compression strength decreased for the increased possibility of serious united and uneven distributed nanoparticles in the materia.When the nanoparticle content equal to 40%,the bending strength decreased 49%and compression strength decreased 21%relatived to the based material.