Preparation of SiC Dispersed Fe0.98Co0.02Si2 by Pressureless Sintering with Cu and Si Addition and Its Thermoelectric Performance
Preparation of SiC Dispersed Fe0.98Co0.02Si2 by Pressureless Sintering with Cu and Si Addition and Its Thermoelectric Performance
复制标题
Cu、Si常压烧结制备SiC分散Fe0.98Co0.02Si2及其热电性能
DOI：
10.2320/matertrans.42.1451
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发表时间：
2001
影响因子：
1.2
通讯作者：
K. Majima
中科院分区：
文献类型：
--
作者：
Mikio Ito;H. Nagai;Takayuki Katsura;S. Katsuyama;K. Majima
在无压烧结的条件下，添加铜和硅，不进行后续热处理以形成β相，合成了碳化硅弥散的β-FeSi2化合物。研究了添加铜和硅对样品的相变、烧结行为和热电性能的影响。在常压烧结过程中，添加铜显著促进了β相的形成，添加铜的样品主要由β相组成，残留有少量的a相和e相。添加铜是致密化的有效手段；铜-硅液相的形成导致了较高的相对密度，达到了90%以上。添加铜的常压烧结样品的热电势和热导率分别比热压样品低得多和高得多。这种差异是由大量的金属相引起的，如e相和Cu-Si相。这些样品的优值系数约为热压样品的1/3，表明Cu的加入完全破坏了碳化硅分散所获得的热电性能的提高。在含铜的样品中，Si的加入通过e+Siβ反应减少了金属e相的数量，增加了半导体→β相的数量。Si的加入显著提高了含铜样品的热电性能和热导率，从而使优值系数显著提高。添加铜和硅的样品的优值与添加碳化硅的热压样品的优值基本相同。
The SiC-dispersed β-FeSi 2 compounds were synthesized by pressureless sintering with Cu and Si addition without a subsequent heat treatment for β phase formation. The effects of Cu and Si addition on the phase transformation, sintering behavior, and thermoelectric performance of these samples were investigated. Cu addition significantly accelerated the β phase formation during the pressureless sintering, and the samples with Cu were mostly composed of the β phase with a small amount of the residual a and e phases. Cu addition was effective for densification; Cu-Si liquid phase formation resulted in a high relative density of over 90%. The thermoelectric power and thermal conductivity of the pressurelessly sintered samples with Cu addition were quite lower and higher, respectively, than those of the hot-pressed sample. The differences were caused by a larger amount of metallic phases, such as the e and Cu-Si phases. The figure of merit of these samples was about 1/3 of that of the hot-pressed sample, indicating that Cu addition completely ruined the enhancement of thermoelectric performance obtained by SiC dispersion. The addition of Si to the samples with Cu decreased the amount of the metallic e phase and increased the amount of the semiconducting β phase through the reaction e + Si → β. The thermoelectric power and thermal conductivity of the samples with Cu were markedly improved by Si addition, which resulted in a significant increase in the figure of merit. The values of the figure of merit for the samples with Cu and Si addition were almost the same as that of the hot-pressed sample with SiC dispersion.