本文選題：YSZ粉末 + 固相合成　； 參考：《湖南大學(xué)》2015年碩士論文

【摘要】：Y2O3穩(wěn)定的ZrO2 (YSZ)陶瓷材料由于具有高熱膨脹系數(shù)、低熱導(dǎo)率以及良好的抗氧化性和熱穩(wěn)定性等優(yōu)異性能,已經(jīng)被廣泛應(yīng)用于制備熱障涂層。納米YSZ材料由于具有納米效應(yīng)而呈現(xiàn)出更多優(yōu)異的特性,如熱膨脹系數(shù)更高、韌性更好、熱導(dǎo)率更低等,因此,采用納米YSZ粉末制備熱障涂層具有一定的潛在實(shí)用價(jià)值且成為熱障涂層領(lǐng)域的研究熱點(diǎn)。本文分別采用固相合成法、共沉淀法和溶膠-凝膠法合成YSZ陶瓷粉末,研究工藝參數(shù)對(duì)粉末相穩(wěn)定性和形貌等影響。主要研究結(jié)果如下：(1)采用固相合成法制備YSZ粉末,研究發(fā)現(xiàn),煅燒溫度、煅燒時(shí)間、Y2O3摻雜量對(duì)產(chǎn)物相結(jié)構(gòu)有重要影響。經(jīng)1400～1600℃溫度范圍內(nèi)煅燒12-36h后,9YSZ粉末中同時(shí)存在單斜相和四方相,單斜相的含量隨著煅燒溫度的升高和時(shí)間的延長(zhǎng)而逐漸減少。相同的煅燒溫度和時(shí)間條件下,YSZ產(chǎn)物中單斜相含量隨Y2Os摻雜量的增加而減少。(2)采用共沉淀法制備納米YSZ粉末的過(guò)程中,pH值和乙醇用量對(duì)四方相的穩(wěn)定性影響不大,不同pH和乙醇用量制備的納米8YSZ粉末中四方相向單斜相轉(zhuǎn)變均發(fā)生在1200℃。納米YSZ粉末中四方相的穩(wěn)定性隨Y2O3摻雜量的增加而提高,樣品3YSZ、5YSZ、7YSZ和8YSZ中四方相向單斜相轉(zhuǎn)變的溫度分別為600、800、1000和1200℃。納米YSZ粉末的晶粒生長(zhǎng)趨勢(shì)一致,晶粒尺寸隨溫度的升高而逐漸增大。晶粒生長(zhǎng)可以分為兩個(gè)階段,以800℃為界。在低溫生長(zhǎng)階段,晶體生長(zhǎng)速率較小；反之,晶體生長(zhǎng)速率明顯增大。由于晶體生長(zhǎng)機(jī)制不同,納米YSZ粉末的晶粒生長(zhǎng)活化能在低溫生長(zhǎng)階段和高溫生長(zhǎng)階段有所不同,且低溫生長(zhǎng)階段的晶體生長(zhǎng)活化能明顯小于高溫生長(zhǎng)階段的生長(zhǎng)活化能。相對(duì)來(lái)講,pH值、溶劑組成和Y2O3摻雜量對(duì)低溫生長(zhǎng)階段的晶體生長(zhǎng)活化能影響較�。欢邷厣L(zhǎng)階段的生長(zhǎng)活化能隨pH值和Y2O3摻雜量的增加而增加,隨乙醇用量的增加先減小后增加。(3)以水為溶劑,醋酸與鋯離子摩爾比為1：1,采用溶膠-凝膠法合成了穩(wěn)定的四方相8YSZ納米粉末。溶劑中添加乙醇后,四方相結(jié)構(gòu)的穩(wěn)定性變差。納米8YSZ粉末經(jīng)400-1200℃溫度范圍內(nèi)熱處理2h后,晶粒尺寸隨著熱處理溫度的升高逐漸增大。晶體生長(zhǎng)可以分為兩個(gè)階段,分別為低溫生長(zhǎng)階段和高溫生長(zhǎng)階段。低溫生長(zhǎng)階段的晶體生長(zhǎng)速率明顯小于高溫生長(zhǎng)階段的晶體生長(zhǎng)速率。納米8YSZ粉末在低溫生長(zhǎng)階段和高溫生長(zhǎng)階段的晶體生長(zhǎng)活化能不同,這主要與晶體生長(zhǎng)機(jī)制發(fā)生改變有關(guān)。醋酸和乙醇用量對(duì)納米8YSZ粉末的晶體生長(zhǎng)活化能有不同的影響。在低溫生長(zhǎng)階段,晶體生長(zhǎng)活化能隨著醋酸用量的增加先減小后增加,隨乙醇用量的增加而減��；在高溫生長(zhǎng)階段,晶體生長(zhǎng)活化能隨醋酸用量的增加先增大后減小,隨乙醇用量的增加先減小后增加。
[Abstract]:Y2O3 stabilized ZrO2 YSZ ceramics have been widely used in the preparation of thermal barrier coatings due to their excellent properties such as high thermal expansion coefficient, low thermal conductivity, good oxidation resistance and thermal stability. Nanocrystalline YSZ materials exhibit more excellent properties such as higher coefficient of thermal expansion, better toughness, lower thermal conductivity and so on. The preparation of thermal barrier coatings using nanometer YSZ powder has a certain potential practical value and has become a research hotspot in the field of thermal barrier coatings. In this paper, YSZ ceramic powders were synthesized by solid state synthesis, coprecipitation and sol-gel methods, respectively. The effects of process parameters on the phase stability and morphology of the powders were studied. The main results are as follows: (1) YSZ powder was prepared by solid state synthesis. It was found that the doping amount of Y _ 2O _ 3 and calcination temperature had an important influence on the phase structure of the product. After calcined at 1 400 鈩，

本文編號(hào)：1800232