Abstract
In recent years, the development of techniques for the controlled preparation of functional graded materials (FGMs) has become a vigorous research field. In this study, to improve the efficiency and accuracy of sample preparations, an automated feeding system based on gravimetric principles for dry powder with three dosing feeders is designed and realized. The feeding rate and accuracy can be regulated by coordinating the protruded length L (mm) and rotational speed V (r/min) of the feeder stirrer. To demonstrate this automatic sample preparation system, the well-known thermoelectric material BixSb2−xTe3 (x = 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8) is selected and prepared by the developed system, and the composition distribution of the functional graded material is characterized. Experimental results show that the BixSb2−xTe3 (x = 0.3–0.8) functionally graded material crystalizes in the rhombohedral phase after hot-pressing sintering and annealing and the prepared sample has a good gradient composition distribution. This verifies the reliability and accuracy of the feeding system. The concept of samples with a gradient component and application of the automatic powder feeding system could considerably accelerate the research and development of new materials.
Highlights
Thermoelectricity is currently considered as a plausible means of producing ‘‘clean’’ electrical energy from virtually any type of waste heat [1]
To improve the efficiency and accuracy of sample preparations, an automated feeding system based on gravimetric principles for dry powder with three dosing feeders is designed and realized
functional graded materials (FGMs) are a useful means of improving the efficiency and usable temperature range of thermoelectrics
Summary
Thermoelectricity is currently considered as a plausible means of producing ‘‘clean’’ electrical energy from virtually any type of waste heat [1]. Functional graded materials (FGMs) have primarily been studied for fabricating thermoelectric modules for assembling and welding of p- and n- legs to enhance the thermoelectric energy conversion efficiency in thermoelectrics [2]. FGMs are a useful means of improving the efficiency and usable temperature range of thermoelectrics. An FGM can undergo a continuous change in composition with annealing and other processes. It might be used as an ideal sample to screen out the sample composition with the best thermoelectric performance. An FGM with a quasi-continuous composition distribution satisfies the sample requirement of the emerging materials genome initiative (MGI) and could lead to further research and improvements in thermoelectric conversion efficiency
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