Preparation And Optimizing Fabrication Process Of Ba₈Cu₄Si₄₂ Thermoelectric Clathrate

thermoelectrical material is a kind of clathrate compounds which was considered as a promising thermoelectrical material. The ZT value of Ba8Cu4Si42 compound can reach 0.28. Meanwhile it has many obvious advantages, such as simple structure, noiseless,no pollution, easy miniaturization, and no moving components. Therefore it is friendly to environment, and has a longer working period.This paper has done lots of work on the preparation and thermoelectric properties of Ba8Cu4Si42 in detail, the method of synthesis compound also researched and optimized. At first, constituents were put into a silica tube, then sealing the quartz tube(under a vacuum circumstance). Followed by alloying and melting constituents by induction furnace and the electric arc furnace. finally,samples were manufactured after annealing,manually grinding and hot pressing. The highest ZT of samples can reach 0.134 at 600?.It is well known that sample fabrication process significantly influences the phase constitution, which then, optimizations on production methods can bring a higher ZT. Via series of experiments, we can conclude that ball milling sample has a highest ZT(0.22) at 350?, and the melt spinning sample's ZT can reached 0.21.The sample gotten via melt spinning and when the temperature is 600?, the ZT reaches the highest value, which is 0.28 while the value of sample by annealing milling grinding and hand milling are 0.23 and 0.17, respectively. When temperature is 487?,the ZT value of sample by annealing milling grinding get the highest, which is 0.25.Samples are characterized using XRD diffraction and Electron Microprobe to obtain phase constitutions and microstructures. Combined the measured thermoelectric properties, the relation between phase composition, micro structure and thermoelectric properties is established, and found the best way to Synthetic samples. Results indicate that the sample experienced annealing, ball milling and hot pressing and that experienced melt spinning, hand milling and hot pressing are of the best ZT in this system.