本文關(guān)鍵詞： MgSiO3 介電常數(shù) 品質(zhì)因子 高壓燒結(jié) 抗彎強(qiáng)度　出處：《武漢理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：本文的主要研究目的是探索高壓制備微波介電陶瓷的新方法。通過對介電陶瓷研究現(xiàn)狀的調(diào)研,提出以硅酸鎂(MgSiO3)微波介電陶瓷的快速燒結(jié)作為本文的研究內(nèi)容。實(shí)驗(yàn)以氧化鎂(MgO)和二氧化硅(SiO2)為原料、國產(chǎn)六面頂大腔體液壓機(jī)為實(shí)驗(yàn)平臺。在燒結(jié)實(shí)驗(yàn)之前,對六面頂大腔體液壓機(jī)的腔體壓力和溫度進(jìn)行了標(biāo)定,并且與已有的標(biāo)定結(jié)果進(jìn)行了對比,證實(shí)了腔體壓力和活塞直徑之間存在平方正比關(guān)系。選擇不同的燒結(jié)壓力、溫度和時間,制備了七組MgSiO3介電陶瓷。對陶瓷樣品進(jìn)行了密度、XRD、SEM、介電參數(shù)和力學(xué)特征測量,結(jié)論如下:1.在選擇合適的壓力和燒結(jié)溫度的前提下,幾分鐘之內(nèi)即可實(shí)現(xiàn)陶瓷體的燒結(jié);在高壓燒結(jié)過程中,MgSiO3可能發(fā)生結(jié)構(gòu)相變。常壓下制備的MgSiO3屬于單斜晶系,當(dāng)壓力在4GPa、燒結(jié)溫度高于1100℃時,MgSiO3轉(zhuǎn)變?yōu)檎痪?2.燒結(jié)溫度的升高和時間的延長,都可以促進(jìn)MgSiO3晶粒的生長,提高燒結(jié)壓力的作用則恰好相反。晶粒越小陶瓷體的密度和抗彎強(qiáng)度越大;3.高壓燒結(jié)的MgSiO3介電陶瓷,其介電常數(shù)最低值為6.7,達(dá)到了微波介電陶瓷的特性要求,并且燒結(jié)體具備較好的力學(xué)強(qiáng)度;4.燒結(jié)體晶粒較大、密度較高時燒結(jié)體介電常數(shù)較小,品質(zhì)因子相對較高。由于晶粒的異常生長導(dǎo)致晶粒分布不均勻,晶粒間結(jié)合情況發(fā)生變化,品質(zhì)因子增大的同時隨頻率的波動也會更加明顯。本文借助高壓設(shè)備,在極短時間內(nèi)燒結(jié)出高致密度的MgSiO3陶瓷,一方面表明高壓作為輔助條件可以極大程度地提高燒結(jié)效率,為介電陶瓷的制備提供了新的參考方法,另一方面也表明在微波頻段(K波段)MgSiO3陶瓷的介電損耗相對較大,在Mg-Si-O體系的微波介電陶瓷燒結(jié)過程中,應(yīng)當(dāng)盡量避免MgSiO3的形成。
[Abstract]:The main purpose of this paper is to explore a new method for preparing microwave dielectric ceramics at high voltage. The rapid sintering of MgSiO _ 3 microwave dielectric ceramics is proposed as the research content in this paper. The materials of the experiment are MgO _ (2) and Sio _ (2). Before the sintering experiment, the pressure and temperature of the chamber were calibrated, and the results were compared with the existing calibration results. It is confirmed that there is a square proportional relationship between cavity pressure and piston diameter. Seven groups of MgSiO3 dielectric ceramics were prepared by selecting different sintering pressure, temperature and time. SEM, dielectric parameters and mechanical characteristics are measured. The conclusions are as follows: 1. Sintering of ceramic body can be realized in a few minutes under the premise of selecting appropriate pressure and sintering temperature; The MgSiO3 prepared under normal pressure belongs to monoclinic system. When the pressure is 4 GPA, the sintering temperature is higher than 1100 鈩，

本文編號：1473356