本文關(guān)鍵詞：鎳基高溫合金上S型薄膜熱電偶的制備及性能研究　出處：《電子科技大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： S型薄膜熱電偶 塞貝克系數(shù) 熱電性能 鎳基高溫合金 渦輪葉片

【摘要】：在航空發(fā)動機設(shè)計驗證過程中,熱端部件(例如渦輪葉片)的表面溫度及溫度分布對部件機械強度和使用壽命影響至關(guān)重要,如何在發(fā)動機工作的惡劣環(huán)境中實現(xiàn)對其實時、精確測量成為急需解決的技術(shù)難題。相比傳統(tǒng)方法的局限性,薄膜熱電偶克服了干擾流場、會破壞機械結(jié)構(gòu)等缺點。通過薄膜沉積技術(shù)將薄膜熱電偶直接制備于被測件表面,與其一體化集成,因此具有結(jié)構(gòu)尺寸小、對測試環(huán)境基本無影響、響應(yīng)速度快、熱容量小等優(yōu)點,在表面溫度測量方面具有明顯的優(yōu)勢。由PtRh和Pt材料組成的S型薄膜熱電偶測溫范圍廣,熱電性能穩(wěn)定,是目前最具應(yīng)用前景的測溫器件之一。本文在前期工作的基礎(chǔ)上,對Pt Rh和Pt薄膜以及S型薄膜熱電偶的制備及性能展開深入研究:首先,采用磁控濺射方法在氧化鋁陶瓷基片上沉積了PtRh和Pt薄膜,系統(tǒng)研究了基片溫度、薄膜厚度、退火處理等對PtRh和Pt薄膜表面形貌、電學(xué)性能、晶體結(jié)構(gòu)的影響。結(jié)果顯示,隨著基片溫度的升高,PtRh和Pt薄膜結(jié)構(gòu)趨于致密,且在基片溫度為400℃時電阻率分別降至3.34×10-5Ω·cm和1.89×10-5Ω·cm。隨著薄膜厚度的增加兩種薄膜均保持較為穩(wěn)定的電學(xué)性能。經(jīng)過退火處理的Pt Rh和Pt薄膜致密性進一步提高,且在退火溫度高于800℃、退火時間大于60 min條件下電阻率保持為穩(wěn)定值。PtRh薄膜在大氣環(huán)境900℃時表面存在一定的銠元素氧化現(xiàn)象,高于1000℃后有所回復(fù)。其次,在氧化鋁陶瓷基片上制備了S型薄膜熱電偶,通過靜態(tài)標定研究了基片溫度、薄膜厚度、退火處理等制備工藝條件對S型薄膜熱電偶熱電性能的影響。結(jié)果顯示,基片溫度為400℃時S型薄膜熱電偶塞貝克系數(shù)中的散射系數(shù)得到明顯下降,對應(yīng)輸出熱電勢在1000℃時相比室溫提高了6.78%。薄膜厚度的增加能夠有效改善S型薄膜熱電偶輸出熱電勢的穩(wěn)定性,且塞貝克系數(shù)基本保持不變;真空800℃退火處理進一步減小了散射系數(shù),輸出熱電勢在1000℃時相比未退火提高了9.08%。在基片溫度為400℃條件,薄膜厚度為1μm,并經(jīng)過真空800℃退火處理60 min得到的S型薄膜熱電偶,在300℃至1000℃范圍內(nèi)平均塞貝克系數(shù)達到12.10μV/℃,靈敏度K值整體大于0.9,最大溫度梯度時的相對誤差為-1.85%。最后,分別在鎳基高溫合金上和渦輪葉片上制備了S型薄膜熱電偶,器件結(jié)構(gòu)由下至上分別為Ni Cr Al Y合金過渡層、熱生長Al2O3層、Al2O3絕緣層和功能層。結(jié)果顯示,在300℃至1000℃范圍鎳基高溫合金上的S型薄膜熱電偶輸出熱電勢具有良好的線性度和重復(fù)性,由于與基片熱交換率的提高略小于陶瓷基底,平均塞貝克系數(shù)為10.16μV/℃,靈敏度K值整體穩(wěn)定于0.84至0.90,最大溫度梯度時的相對誤差為-0.52%。渦輪葉片表面的S型薄膜熱電偶經(jīng)過靜態(tài)標定和冷效試驗考核,仍能夠保持熱電偶結(jié)構(gòu)完整,并且表現(xiàn)出較好的器件性能。
[Abstract]:In the process of aeroengine design verification, the influence of surface temperature and temperature distribution of hot end components (such as turbine blades) on the mechanical strength and service life of components is very important. How to realize real-time and accurate measurement of engine in bad environment is a technical problem that needs to be solved. Compared with the limitation of traditional method, thin film thermocouple overcomes the interference flow field. The thin film thermocouple is directly prepared on the surface of the tested part by thin film deposition technology and integrated with it, so it has small structure size and has no effect on the test environment. Because of its high response speed and small thermal capacity, it has obvious advantages in surface temperature measurement. The S-type thin film thermocouple composed of PtRh and Pt has a wide range of temperature measurement and stable thermoelectric performance. Based on the previous work, the preparation and performance of Pt Rh, Pt thin film and S-type thin film thermocouple are studied. PtRh and Pt thin films were deposited on alumina substrates by magnetron sputtering. The surface morphology and electrical properties of PtRh and Pt films were systematically studied by substrate temperature, film thickness and annealing treatment. The results show that the structure of PtRh and Pt films tend to be compact with the increase of substrate temperature. The resistivity decreases to 3.34 脳 10 ~ (-5) 惟 路cm and 1.89 脳 10 ~ (-5) 惟 路cm at 400 鈩，

本文編號：1366330