【摘要】：氮氧化鋁(γ-AlON)透明陶瓷是一種重要的尖晶石結(jié)構(gòu)材料,由于非化學計量比特點,γ-AlON晶體中包含大量的缺陷微結(jié)構(gòu),對材料性能產(chǎn)生顯著影響。目前,人們對γ-AlON缺陷微結(jié)構(gòu)的研究較少,對于γ-AlON材料性能的報導存在較大差異。本課題采用紫外輻照和退火處理等方法,利用光催化反應儀、熒光分光光度計和熱釋光光譜儀等檢測設(shè)備,對γ-AlON材料中的缺陷微結(jié)構(gòu)及其形成機理進行了詳細的研究,具體內(nèi)容和主要結(jié)論如下：(1)γ-AlON粉體為純凈的尖晶石結(jié)構(gòu),尺寸分布300-900 nm,平均粒經(jīng)約580nm,無團聚現(xiàn)象,禁帶寬度5.2 eV,內(nèi)含大量的鋁空位等缺陷。γ-A10N粉體在2h內(nèi),對甲基橙溶液(10mg/L)紫外降解率達到92%。分析表明：γ-AlON晶體中缺陷能級電子躍遷形成的電子-空穴對,在大量缺陷阱輔助作用下有效分離,與甲基橙分子反應并將其降解；(2)γ-AlON透明陶瓷紫外(汞燈)輻照15mmin后,樣品由無色變?yōu)樗{紫色；其透過光譜中550 nm處出現(xiàn)明顯光吸收,與輻照樣品呈現(xiàn)藍紫色相一致。樣品中鋁空位等缺陷產(chǎn)生的誘導色心,隨退火過程表現(xiàn)出一定的遷移性,250℃低溫退火即可將其“漂白”；(3)γ-AlON晶體缺陷形成機理為：[Al24O24N8]+3/202→[Al23027N5]+3[ON']+ [VA1],主要缺陷結(jié)構(gòu)為VAl"'和ON·,理論濃度1/56。VAl"'和ON·在靜電作用下形成[VAl-ON].[ON'-VAl"-ON']'和[VAl-30N]等缺陷簇,它們是樣品出現(xiàn)輻照誘導著色的根源；(4)y-A1ON透明陶瓷在紫外(371 nm)和可見光范圍(707 nm)內(nèi)均表現(xiàn)出明顯的熒光特性,起源于[VAl-ON'].[ON'-VAl一ON]'口[VAl-3ON]等缺陷能級。分析表明：γ-AlON晶體結(jié)構(gòu)穩(wěn)定,高溫退火處理只影響缺陷擴散運動,表述為：[VAl-3ON] (?)[ON-VAl-ON]'+ON'(?)[VAl-ONr+20N'(?)VAl+30N',從而引起缺陷簇的結(jié)合形式或相對濃度改變；紫外輻照對缺陷結(jié)構(gòu)無影響,不會改變熒光特性。
[Abstract]:Alumina nitride (緯-AlON) transparent ceramics is an important spinel structure material. Due to the non-stoichiometric characteristics, 緯-AlON crystal contains a large number of defective microstructures, which have a significant impact on the properties of the materials. At present, there are few studies on the microstructure of 緯-AlON defects, and there are great differences in the reports of the properties of 緯-AlON materials. In this paper, the defect microstructure and formation mechanism of 緯-AlON materials were studied by means of ultraviolet irradiation and annealing, using photocatalytic reaction apparatus, fluorescence spectrophotometer and thermoluminescence spectrometer. The specific contents and main conclusions are as follows: (1) 緯-AlON powder is pure spinel structure, the size distribution of 300-900 nm, average particle size is about 580nm, there is no agglomeration, the gap width 5.2 eV, contains a lot of aluminum vacancies and so on. 緯 -A10N powder contains a lot of aluminum vacancies within 2 hours. The UV degradation rate of p-methyl orange solution (10mg/L) was 92%. The results show that the electron-hole pair formed by the electron transition of defect level in 緯-AlON crystal is effectively separated by a large number of traps and reacted with methyl orange molecule and degraded. (2) 緯-AlON transparent ceramics irradiated by UV (mercury lamp), The sample changed from colorless to blue purple, and there was obvious light absorption at 550 nm through the spectrum, which was consistent with that of irradiated sample. The induced color center produced by the defects such as aluminum vacancy in the sample shows a certain migration with the annealing process, and it can be "bleached" after low temperature annealing at 250 鈩，

本文編號：2275318