【摘要】：本論文圍繞納米晶鈦酸鋇顆粒材料的研究展開(kāi),獨(dú)創(chuàng)了“一步溶膠法”,在低溫下制備出了晶粒尺寸小于10nm的一系列高結(jié)晶度鈦酸鋇粉體及顆粒薄膜,系統(tǒng)地對(duì)10nm以內(nèi)小尺寸鈦酸鋇的相結(jié)構(gòu)及物理性能展開(kāi)了研究,探討了鈦酸鋇維持鐵電性的極限尺寸,并成功地將其應(yīng)用在儲(chǔ)能薄膜和鎳粉包覆技術(shù),實(shí)現(xiàn)了鈦酸鋇納米晶顆粒材料的有效應(yīng)用。通過(guò)對(duì)鈦酯水解-交聯(lián)反應(yīng)速率的精準(zhǔn)控制,獨(dú)創(chuàng)了介于溶膠凝膠法和沉淀法之間的“一步溶膠法”,常壓下制備出了平均晶粒尺寸小至2.8nm的結(jié)晶型鈦酸鋇顆粒及其穩(wěn)定溶膠。該方法成功地應(yīng)用于方形鈦酸鍶納米晶及其穩(wěn)定溶膠的制備。采用該穩(wěn)定溶膠在160℃的低溫下制備出了高結(jié)晶度的鈦酸鹽顆粒薄膜。利用拉曼、同步輻射衍射、成對(duì)分布函數(shù)(PDF)和X射線光電子能譜(XPS)分析發(fā)現(xiàn)小至2.8nm的鈦酸鋇顆粒呈現(xiàn)多相共存的結(jié)構(gòu)特征,非中心對(duì)稱相含量與顆粒表面結(jié)構(gòu)密切相關(guān)。其相變過(guò)程十分彌散,分布在較寬的溫度范圍內(nèi),且非中心對(duì)稱的四方、正交相結(jié)構(gòu)在400℃的高溫下依然存在,首次證實(shí)了小至2.8nm的鈦酸鋇顆粒依然具有鐵電性。對(duì)納米晶鈦酸鋇顆粒進(jìn)行了一系列的物理性能分析表征。二次諧波產(chǎn)生(SHG)實(shí)驗(yàn)證實(shí)了這些納米晶顆粒在室溫下具有非線性極化效應(yīng),并且SHG響應(yīng)隨溫度的升高逐漸下降,呈現(xiàn)出由非中心對(duì)稱的鐵電相結(jié)構(gòu)逐漸向順電相轉(zhuǎn)變的趨勢(shì)。顆粒在外加電場(chǎng)下的極化翻轉(zhuǎn)行為和介電性能測(cè)試均進(jìn)一步證實(shí)了小至2.8nm的鈦酸鋇顆粒具有鐵電性。最后本文對(duì)這些納米晶顆粒在多方面的應(yīng)用進(jìn)行了探索。利用獲得的穩(wěn)定溶膠在≤160℃的低溫下制得了高結(jié)晶度的鈦酸鹽顆粒薄膜,薄膜呈現(xiàn)良好的介電特性和溫度穩(wěn)定性;通過(guò)多層化結(jié)構(gòu)設(shè)計(jì),具有鐵電性的8nm鈦酸鋇顆粒在有機(jī)-無(wú)機(jī)復(fù)合材料中獲得了高的電位移極化,有效地實(shí)現(xiàn)了復(fù)合薄膜的高擊穿場(chǎng)強(qiáng)(495kV/mm)和高儲(chǔ)能密度(19.37J/cm3);將納米晶鈦酸鋇材料的制備方法應(yīng)用于鎳粉表面的包覆改性,通過(guò)快速高效的一步反應(yīng)形成了致密均勻的鈦酸鋇多晶包覆層,有效延緩了納米鎳粉的燒結(jié)收縮并改善了其抗氧化性能。
[Abstract]:In this paper, a series of high crystallinity barium titanate powders and granular films with grain size smaller than 10nm were prepared at low temperature by "one-step sol method", focusing on the research of nanocrystalline barium titanate particles. The phase structure and physical properties of small size barium titanate in 10nm are systematically studied. The limiting size of barium titanate to maintain ferroelectric properties is discussed, and successfully applied to the coating technology of energy storage film and nickel powder. The effective application of nanocrystalline barium titanate material has been realized. By precisely controlling the rate of hydrolysis and crosslinking of titanium esters, a one-step sol method was created between sol-gel method and precipitation method. Crystallized barium titanate particles with average grain size as small as 2.8nm and their stable sol were prepared under atmospheric pressure. The method has been successfully applied to the preparation of cubic strontium titanate nanocrystalline and its stable sol. Titanate granular films with high crystallinity were prepared by using the stable sol at low temperature of 160 鈩，

本文編號(hào)：2330672