本文選題：熱電材料　切入點：Bi2S3　出處：《湘潭大學》2015年碩士論文　論文類型：學位論文

【摘要】：熱電材料是一種能實現(xiàn)熱能和電能相互轉(zhuǎn)換的功能材料,用其制成的熱電器件,既能夠利用工業(yè)生產(chǎn)中的廢熱進行發(fā)電,同時也能用作制冷設(shè)備。熱電器件具有環(huán)境污染小、噪聲污染低、重量輕、體積小、工作性能穩(wěn)定等優(yōu)點,因此熱電材料的開發(fā)與應(yīng)用受到科研工作者們的密切關(guān)注。Bi2S3作為一種低溫熱電材料,在室溫下具有較低的熱導(dǎo)率。采用儲量豐富的S替代了最常用熱電材料Bi2Te3中昂貴的稀有元素Te,大大降低了材料的成本,對于熱電材料的研究具有重要意義。因此本論文以Bi2S3基熱電材料的制備和性能表征為主,系統(tǒng)的研究了不同第二相復(fù)合對Bi2S3熱電材料性能的影響。研究的主要內(nèi)容包括以下幾個方面:1.采用水熱法制備了Bi2S3粉末,之后采用等離子燒結(jié)(SPS)技術(shù)制備了塊體樣品,系統(tǒng)地研究了水熱合成溫度、添加劑對樣品形貌的影響,同時測試了樣品的熱電性能。實驗結(jié)果表明:水熱法合成的Bi2S3粉末都具有由條狀納米晶聚集而成的球狀形貌,180°C下合成的粉末平均晶粒尺寸比150°C的小;當表面活性劑乙二醇的添加量為12 m L時,粉末的晶粒尺寸有明顯的降低;隨著十二烷基苯磺酸添加量的增加,粉末樣品逐漸由球形向圓餅狀形貌轉(zhuǎn)變;樣品的熱電性能總體趨勢與文獻報道的相近,575 K時樣品的ZT值為0.1。2.采用水熱法結(jié)合SPS技術(shù)制備了BiCl3/Bi2S3復(fù)合塊體,系統(tǒng)地研究了BiCl3復(fù)合量對樣品熱電性能的影響。實驗結(jié)果表明SPS后樣品的晶粒尺寸有所增加;適量的BiCl3復(fù)合Bi2S3既降低了樣品的熱導(dǎo)率,又提高了樣品的電導(dǎo)率;樣品的ZT值隨著溫度的升高而升高,當BiCl3復(fù)合量為0.25%時樣品的ZT值最大,在724.3 K時達到了0.63,約為純Bi2S3樣品ZT值的3倍。3.采用水熱法結(jié)合SPS技術(shù)制備了Ag2S/Bi2S3復(fù)合粉末及其塊體樣品,系統(tǒng)地研究了Ag2S復(fù)合量對樣品形貌和熱電性能的影響。實驗結(jié)果表明隨著Ag2S復(fù)合量的增加,樣品中球形逐漸向圓餅狀結(jié)構(gòu)轉(zhuǎn)變,但仍然保持分級結(jié)構(gòu)的形貌特征;Ag2S/Bi2S3復(fù)合粉末樣品的熱導(dǎo)率都比純Bi2S3樣品的熱導(dǎo)率低,當Ag2S復(fù)合量為3%時其ZT值最高,在724.3 K時達到了0.23。4.采用水熱法結(jié)合SPS技術(shù)制備了Ag2S、BiCl3雙復(fù)合Bi2S3樣品,系統(tǒng)地研究了Ag2S、BiCl3復(fù)合量對Bi2S3樣品熱電性能的影響。實驗結(jié)果表明雙相復(fù)合樣品的電導(dǎo)率有明顯的提高,Bi2S3復(fù)合5%Ag2S和1%BiCl3樣品具有最大的ZT值,在724.3 K時達到了0.59,比5%Ag2S復(fù)合樣品的ZT值提高了近5倍。
[Abstract]:Thermoelectric material is a kind of functional material which can realize the conversion of heat energy and electric energy. The thermoelectric device made of thermoelectric device can not only generate electricity from waste heat in industrial production, but also be used as refrigeration equipment. Because of the advantages of low noise pollution, light weight, small volume and stable working performance, the development and application of thermoelectric materials have been paid close attention to by researchers. Bi2S3 is a kind of low-temperature thermoelectric material. It has low thermal conductivity at room temperature. The expensive rare element Tein in the most commonly used thermoelectric material Bi2Te3 is replaced by S with abundant reserves, which greatly reduces the cost of the material. Therefore, the preparation and characterization of thermoelectric materials based on Bi2S3 are the main topics in this thesis. The effects of different second phase compounding on the properties of Bi2S3 thermoelectric materials were systematically studied. The main contents of the study included the following aspects: 1.The Bi2S3 powder was prepared by hydrothermal method, and then bulk samples were prepared by plasma sintering. The effects of hydrothermal synthesis temperature and additives on the morphology of the samples were systematically studied. At the same time, the thermoelectric properties of the samples were tested. The experimental results showed that the average grain size of the Bi2S3 powders synthesized by hydrothermal method was smaller than that of 150 擄C with spherical morphology of 180 擄C, which was formed from the aggregation of nanocrystalline stripes. When the amount of surfactant ethylene glycol was 12 mL, the grain size of the powder decreased obviously, and with the increase of 12 alkyl benzenesulfonic acid, the morphology of powder gradually changed from spherical to round shape. The general trend of the thermoelectric properties of the samples is 0.1.2 when the samples are close to 575K reported in the literature. The BiCl3/Bi2S3 composite blocks were prepared by hydrothermal method combined with SPS technology. The effects of BiCl3 composition on the thermoelectric properties of the samples were systematically studied. The experimental results showed that the grain size of the samples increased after SPS, and the proper amount of BiCl3 composite Bi2S3 not only decreased the thermal conductivity of the samples, but also improved the conductivity of the samples. The ZT value of the sample increases with the increase of temperature. The ZT value of the sample reaches 0.63 at 724.3 K when the amount of BiCl3 compound is 0.25, which is about 3 times of the ZT value of pure Bi2S3 sample. The Ag2S/Bi2S3 composite powder and its bulk samples were prepared by hydrothermal method and SPS technique. The effects of Ag2S composition on the morphology and thermoelectric properties of the samples were systematically studied. The experimental results showed that the sphericity of the samples gradually changed to the round shape structure with the increase of the Ag2S composition. However, the thermal conductivity of Ag2S / Bi2S3 composite powder is lower than that of pure Bi2S3, and the ZT value is the highest when the Ag2S composition is 3. At 724.3 K, it reached 0.23.4.The Ag _ 2S _ 2O _ 3 BiCl _ 3 double composite Bi2S3 sample was prepared by hydrothermal method combined with SPS technique. The influence of the amount of Ag _ 2S _ 2 / BiCl _ 3 on the thermoelectric properties of Bi2S3 samples was systematically studied. The experimental results showed that the conductivity of the two-phase composite samples was significantly improved, and the maximum ZT values of the samples were obtained. At 724.3 K, the ZT value of the composite sample is 0.59, which is nearly 5 times higher than that of the 5Ag2S composite sample.
【學位授予單位】：湘潭大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ135.32

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本文編號：1578180