本文選題：非傳統(tǒng)晶化 + 金紅石　； 參考：《浙江大學(xué)》2016年碩士論文

【摘要】：晶化在固體化學(xué)、生物以及材料科學(xué)中都有著根本重要性,是科學(xué)中研究最多的過程之一,同時也是具有極大實(shí)際價值。在經(jīng)典的晶體生長理論建立一百多年來,傳統(tǒng)成核和熱力學(xué)/動力學(xué)生長模型取得了巨大成功,但現(xiàn)在仍有許多晶化行為是經(jīng)典理論所無法解釋的。并且,過去的晶化研究往往只是局限于表面形貌,未能真正將晶化過程中表面形貌與內(nèi)部結(jié)構(gòu)演變相結(jié)合來研究其生長機(jī)理。近些年來,聚焦離子束微納加工技術(shù)和球差校正電鏡技術(shù)的發(fā)展為同時研究微米級顆粒內(nèi)/外結(jié)構(gòu)提供了可能。本文主要利FIB和TEM技術(shù)來研究非平衡條件下金紅石晶體的晶化過程,特別是表面/內(nèi)部結(jié)構(gòu)演變以及該過程中發(fā)生的非傳統(tǒng)晶體生長行為。FIB和TEM技術(shù)的交叉運(yùn)用使我們能夠觀察和分析內(nèi)部結(jié)構(gòu)以及缺陷的變化,結(jié)合觀察到的表面結(jié)構(gòu)演變,我們對金紅石晶體的非傳統(tǒng)生長機(jī)理有更加深入的了解。具體如下：(1)利用氫氟酸和鹽酸的協(xié)同吸附效應(yīng)通過簡便的低溫水熱方法可控制備了一種具有新型曲面的金紅石型氧化鈦單晶,揭示了該新型曲面表面結(jié)構(gòu)。結(jié)合理論計算和實(shí)驗(yàn)分析,我們發(fā)現(xiàn)封端劑以及實(shí)驗(yàn)環(huán)境對這種弧形表面的形成和轉(zhuǎn)變有著重大意義。(2)利用聚焦離子束技術(shù)以及透射電鏡技術(shù)去研究曲面金紅石TiO2晶體的內(nèi)部結(jié)構(gòu),發(fā)現(xiàn)了該金紅石晶體中存在一種新奇的競爭生長現(xiàn)象,即生長過程中同時存在兩種生長模式在三維空間上相互競爭。我們研究了其在二維平面上的生長動力學(xué)過程以及三維空間上兩種不同生長模式區(qū)域的分布,分析了這種競爭生長現(xiàn)象存在的原因,并且成功構(gòu)造了晶體內(nèi)部同樣具有該競爭生長的曲面SnO2介晶。該工作首次展示了一種晶體生長過程中同時存在平衡和非平衡兩種生長模式,并半定量地描述兩種生長模式的動力學(xué)過程。(3)引入了一種預(yù)接種的處理方法去研究一種新型的膠囊狀的金紅石TiO2介晶的生長初期的非傳統(tǒng)晶化行為,發(fā)現(xiàn)其可能是由先形成的介孔納米棒團(tuán)簇定向自組裝而成。生長初期出現(xiàn)的那納米膠囊雛形以及晶體連接過程中初級顆粒輕微取向失配現(xiàn)象強(qiáng)有力地證明了定向聚集這一生長行為的存在。
[Abstract]:Crystallization is of fundamental importance in solid chemistry, biology and material science. It is one of the most studied processes in science and has great practical value. Since the classical crystal growth theory has been established for more than 100 years, the traditional nucleation and thermodynamic / kinetic growth models have achieved great success, but there are still many crystallization behaviors that cannot be explained by the classical theory. Moreover, in the past, the study of crystallization was usually confined to the surface morphology, and the growth mechanism was not really studied by combining the surface morphology with the evolution of internal structure in the process of crystallization. In recent years, the development of focused ion beam microfabrication and spherical aberration correction electron microscopy has made it possible to study the inner / outer structure of micron particles simultaneously. In this paper, the crystallization process of rutile crystals under non-equilibrium conditions is studied by using LiFIB and TEM techniques. In particular, the surface / internal structure evolution and the cross-use of non-traditional crystal growth behavior. FIB and TEM techniques during this process enable us to observe and analyse the changes in internal structure and defects, and to combine the observed surface structure evolution. We have a better understanding of the unconventional growth mechanism of rutile crystals. The main results are as follows: (1) A rutile titanium oxide single crystal with a new surface can be controlled by using the synergistic adsorption effect of hydrofluoric acid and hydrochloric acid. The surface structure of the new surface is revealed. Combined with theoretical calculation and experimental analysis, We find that the capping agent and experimental environment are of great significance to the formation and transformation of the curved surface. (2) the internal structure of the curved rutile TiO2 crystal is studied by focusing ion beam technique and transmission electron microscopy. It is found that there is a novel competitive growth phenomenon in the rutile crystal, that is, there are two growth modes competing with each other in the three dimensional space during the growth process. In this paper, we study the dynamic process of growth in two-dimensional plane and the distribution of two different growth modes in three dimensional space, and analyze the reason why the competitive growth phenomenon exists. The surface Sno _ 2 mesocrystals with the same competitive growth in the crystal have been successfully constructed. This work shows for the first time that there are both equilibrium and non-equilibrium growth patterns in the process of crystal growth. The kinetic processes of the two growth modes were described semi-quantitatively. (3) A preinoculation method was introduced to study the unconventional crystallization behavior of a new type of capsule rutile TiO2 mesocrystalline in the early stage of growth. It is found that it may be formed by self-assembly of mesoporous nanorods. The initial appearance of the nanocapsule and the slight misalignment of the primary particles in the process of crystal joining strongly prove the existence of the growth behavior of the directional aggregation.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：O614.411;O782

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