Thermo-electric converting materials, process for producing the same, and thermo-electric converting element

Abstract

A thermo-electric converting material which can stably have high thermo-electric converting performances at about 300-600 DEG C, has high physical strength, does not weather, and has excellent durability. It has high stability and high reliability. Also provided are a process for producing the material and a thermo-electric converting element. Furthermore provided is a thermo-electric converting material obtained from raw materials including a silicon sludge, which has had no uses except for landfill disposal. thermo-electric converting materials are characterized by including, as a major component, a sinter made of magnesium silicide of a polycrystalline structure containing at least one element selected among arsenic, antimony, phosphorus, aluminum, and boron. In the production process, a silicon sludge which has undergone a purification treatment is used.

Description

technical field [0001] The present invention relates to a thermoelectric conversion material, a manufacturing method thereof, and a thermoelectric conversion element. Background technique [0002] In the past, the waste silicon residue discharged when grinding and grinding silicon ingots and silicon wafers made of high-purity silicon used in the manufacture of silicon products such as semiconductors and solar cells is very fine, with a particle size of 0.1 to 10 μm, and In addition to silicon, it also contains boron, phosphorus, tungsten, chromium, titanium, arsenic, gallium, iron, oxygen, etc., which are implanted into the wafer surface in the form of impurities by ion implantation. When adding polyaluminum chloride or aluminum sulfate as a flocculant. [0003] In addition, water can be used to improve lubricity at the time of grinding and grinding. However, since oil and the like are added to the water, many impurities represented by oil and the like are contained in the ...

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Problems solved by technology

[0032] Therefore, conventional attempts have been made to use Bi-Te-based, Co-Sb-based, Zn-Sb-based, Pb-Te-based, and Ag-Sb-Ge-Te-based thermoelectric conversion materials in fuel cells, automobiles, boilers, and incinerators. Electric conversion of waste heat sources at temperatures between 200°C and 800°C, such as blast furnaces, blast furnaces, etc. However, there is a problem that the burden on the environment increases due to the presence of hazardous substances.

[0033] In addition, among materials used in high-temperature applications, B 4 Boron-rich borides such as C, rare earth metal chalcogenides such as LaS, etc., however, B 4 Non-oxide materials based on intermetallic compounds such as C or LaS exhibit relatively high performance in a vacuum, but they have a problem of poor stability in high-temperature regions such as crystal phase decomposition at high temperatures.

[0034] On the other hand, Mg, which has a small environmental burden, has been studied 2 Si (for example, refer to Non-Patent Documents 1, 2, 3), Mg 2 Si 1-x C x (For example, non-refer to Patent Document 4), MnSi 1.75 Such as silicide (silicide) materials, but due to the high chemical reactivity of magnesium, it is very dangerous, etc., there are difficulties in manufacturing, because the manufactured material is brittle, it will be weathered, so there is a problem that it cannot withstand use, Problems such as low thermoelectric conversion performance

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