本文關(guān)鍵詞： 熱障涂層 復(fù)阻抗譜 電場(chǎng)分布 有限元　出處：《湘潭大學(xué)》2015年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：熱障涂層(Thermal Barrier Coatings,簡(jiǎn)稱(chēng)TBCs)是一種絕熱陶瓷涂層,已成功應(yīng)用在航空發(fā)動(dòng)機(jī)的渦輪葉片,以提高渦輪葉片的服役溫度和耐腐蝕性能。然而,TBCs結(jié)構(gòu)復(fù)雜,在惡劣的服役環(huán)境下會(huì)發(fā)生脫落和失效,這不但影響航空發(fā)動(dòng)機(jī)效率,而且嚴(yán)重威脅航空發(fā)動(dòng)機(jī)的安全運(yùn)行。為預(yù)防上述情況發(fā)生,復(fù)阻抗譜檢測(cè)(Impedance Spectroscopy,簡(jiǎn)稱(chēng)IS)作為一種無(wú)損檢測(cè)方法已被應(yīng)用于熱障涂層的結(jié)構(gòu)檢測(cè)和壽命預(yù)測(cè)中。盡管如此,復(fù)阻抗譜檢測(cè)在航空發(fā)動(dòng)機(jī)熱障涂層中的應(yīng)用還存在以下兩個(gè)問(wèn)題:1.對(duì)復(fù)阻抗譜結(jié)果的分析缺乏穩(wěn)定可靠的研究工具。2.實(shí)驗(yàn)中采用的非對(duì)稱(chēng)電極對(duì)復(fù)阻抗譜檢測(cè)結(jié)果的影響不明確。因此,本文引入有限元法對(duì)熱障涂層的復(fù)阻抗譜檢測(cè)進(jìn)行模擬分析,進(jìn)一步研究復(fù)阻抗譜測(cè)量環(huán)境和TBCs結(jié)構(gòu)變化對(duì)熱障涂層復(fù)阻抗譜測(cè)量結(jié)果的影響。主要研究?jī)?nèi)容及所得結(jié)果如下:1.根據(jù)有限元結(jié)果、實(shí)驗(yàn)測(cè)量結(jié)果以及復(fù)阻抗譜理論,詳細(xì)地分析測(cè)量電壓、測(cè)量溫度以及測(cè)量電極大小對(duì)TBCs復(fù)阻抗譜的影響。此外,對(duì)復(fù)阻抗譜進(jìn)行等效電路擬合,得到Y(jié)SZ和TGO的測(cè)量厚度。最后,綜合測(cè)量電壓、測(cè)量溫度以及測(cè)量電極大小的影響,確定TBCs復(fù)阻抗譜最佳的測(cè)量電壓為1 V,測(cè)量溫度為400°C,測(cè)量所用的Pt電極直徑為3~5 mm。2.根據(jù)有限元結(jié)果、實(shí)驗(yàn)結(jié)果及復(fù)阻抗譜理論,分析YSZ、TGO厚度和電導(dǎo)率對(duì)TBCs復(fù)阻抗譜檢測(cè)的影響。通過(guò)比較測(cè)量厚度與模型所設(shè)厚度,確定檢測(cè)的大致誤差,結(jié)果表明:在根據(jù)復(fù)阻抗譜計(jì)算YSZ和TGO厚度時(shí),不應(yīng)直接采用Pt電極面積作為測(cè)量區(qū)域面積,而應(yīng)選取比Pt電極面積大的值。如當(dāng)Pt電極直徑為3 mm時(shí),用于計(jì)算YSZ厚度的測(cè)量區(qū)域面積取值應(yīng)比Pt電極面積大10%,此時(shí)得到的結(jié)果測(cè)量誤差更小。同理,對(duì)于計(jì)算TGO厚度,測(cè)量區(qū)域面積取值則應(yīng)比Pt電極面積大60%。3.采用COMSOL軟件模擬TBCs復(fù)阻抗譜測(cè)量過(guò)程,同時(shí)分析不同條件下TBCs的復(fù)阻抗譜及其內(nèi)部的電場(chǎng)分布。結(jié)果表明:非對(duì)稱(chēng)電極的使用導(dǎo)致TBCs內(nèi)電場(chǎng)線發(fā)散,該發(fā)散是復(fù)阻抗譜檢測(cè)誤差存在的重要原因之一。測(cè)量溫度、測(cè)量電極大小、YSZ和TGO的厚度以及電導(dǎo)率對(duì)復(fù)阻抗譜的影響可從兩個(gè)角度解釋:(1)通過(guò)本身數(shù)值的改變影響TBCs的復(fù)阻抗譜;(2)通過(guò)改變測(cè)量區(qū)域面積影響TBCs的復(fù)阻抗譜。
[Abstract]:Thermal Barrier Coatingsis an adiabatic ceramic coating, which has been successfully used in aero-engine turbine blades to improve the service temperature and corrosion resistance of turbine blades. However, the structure of TBCs is complex. Shedding and failure will occur in harsh service conditions, which not only affect the efficiency of aero-engines, but also seriously threaten the safe operation of aero-engines. Complex Impedance Spectroscopy (ISS) has been used as a nondestructive testing method for structural testing and life prediction of thermal barrier coatings. Application of complex Impedance Spectroscopy in Aero-engine Thermal Barrier Coatings: 1. The analysis of complex impedance spectrum results is short of a stable and reliable research tool .2. the asymmetric electrode pair complex impedance spectrum detection used in the experiment. The effect of the outcome is not clear. In this paper, the finite element method is introduced to simulate the measurement of complex impedance spectrum of thermal barrier coatings. The influence of complex impedance spectrum measurement environment and structure change of TBCs on the measurement results of thermal barrier coating complex impedance spectrum is further studied. The main contents and results are as follows: 1. According to the finite element results, the experimental results and the complex impedance spectrum theory, The influence of measurement voltage, temperature and electrode size on TBCs complex impedance spectrum is analyzed in detail. In addition, the measurement thickness of YSZ and TGO is obtained by the equivalent circuit fitting of complex impedance spectrum. Finally, the comprehensive measurement voltage is obtained. The optimum measurement voltage of TBCs complex impedance spectrum is 1 V, the measurement temperature is 400 擄C, and the diameter of Pt electrode is 3 ~ 5 mm. 2. According to the finite element results, the experimental results and the complex impedance spectrum theory are used. The influence of the thickness and conductivity of YSZ TGO on the measurement of TBCs complex impedance spectrum is analyzed. By comparing the thickness between the measured thickness and the thickness set up by the model, the approximate error of the detection is determined. The results show that the thickness of YSZ and TGO is calculated according to the complex impedance spectrum. The area of Pt electrode should not be used as the measuring area directly, but the value larger than that of Pt electrode should be chosen. For example, when the diameter of Pt electrode is 3 mm, The area of the measuring area used to calculate the thickness of YSZ should be 10 times larger than the area of Pt electrode, and the measurement error of the result obtained at this time is smaller. In the same way, for calculating the thickness of TGO, The area of measurement area should be 60% larger than that of Pt electrode. The COMSOL software is used to simulate the measurement process of TBCs complex impedance spectrum. At the same time, the complex impedance spectrum of TBCs and its internal electric field distribution under different conditions are analyzed. The results show that the use of asymmetric electrode leads to the divergence of electric field line in TBCs, which is one of the important reasons for the existence of complex impedance spectrum measurement error. The influence of the thickness of YSZ and TGO and the conductivity of the electrode on the complex impedance spectrum can be explained from two angles: (1) the complex impedance spectrum of TBCs can be affected by the change of its own value. (2) the complex impedance spectrum of TBCs can be affected by changing the area of measurement area.
【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TQ174.758.16

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本文編號(hào)：1515052