本文選題：堇青石 + 微波介質(zhì)陶瓷�。� 參考：《杭州電子科技大學(xué)》2015年碩士論文

【摘要】：本文主要以堇青石(Mg2Al4Si5O18)微波介質(zhì)陶瓷為研究對(duì)象,針對(duì)堇青石陶瓷的燒結(jié)溫度范圍窄、燒結(jié)溫度高、品質(zhì)因數(shù)Qf低、諧振頻率溫度系數(shù)?f較大等問題,提出相應(yīng)的解決方案。研究范疇包括:物相組成、燒結(jié)特性、微觀形貌、晶格參數(shù)、Si/Al排列順序、[(Si/Al)O4]四面體、以及[(Si4Al2)O18]六元環(huán)的結(jié)構(gòu)變化對(duì)其微波介電性能的影響,并成功制備了性能良好的堇青石基微波介質(zhì)材料。本文的具體內(nèi)容如下:1)在(Mg1 xLax)2Al4Si5O18+x(0≤x≤0.35)陶瓷的改性研究中,La3+完全取代Mg2+離子形成堇青石基固溶體。在0≤x≤0.05時(shí),外圍[(Mg1-xLax)6O36]六元環(huán)結(jié)構(gòu)畸變,對(duì)內(nèi)[(Si4Al2)O18]六元環(huán)產(chǎn)生壓縮應(yīng)力,使[(Si4Al2)O18]六元環(huán)的對(duì)稱性得到提高;然而,在0.05x≤0.10時(shí),擇優(yōu)取代優(yōu)勢(shì)減弱,壓縮應(yīng)力趨于平衡。最終,(Mg1 xLax)2Al4Si5O18+x(x=0.05)陶瓷獲得最佳微波介電性能:?r=6.7,Qf=56,500 GHz,?f=-20.5 ppm/℃。2)在(Mg1 x Yx)2Al4Si5O18+x(0≤x≤0.25)的改性研究中,Y3+的取代形成微量堇青石固溶體。在0x≤0.05時(shí),陶瓷的相對(duì)介電常數(shù)有所增加。當(dāng)0.1≤x≤0.25時(shí),出現(xiàn)第二相Y2Si2O7,表現(xiàn)為Mg2Al4Si5O18/Y2Si2O7的復(fù)合相。在x=0.05時(shí),(Mg1 xYx)2Al4Si5O18+x的微波介電性能為:?r=6.3,Qf=38,900 GHz,?f=-28ppm/℃。3)在(1-x)Mg2Al4Si5O18-xTiO2(0≤x≤0.35)陶瓷的改性研究中,在0≤x≤0.10時(shí),陶瓷呈現(xiàn)堇青石固溶體。在0.10x≤0.35時(shí),陶瓷呈現(xiàn)為Mg2Al4Si5O18/TiO2的復(fù)合相。(1-x)Mg2Al4Si5O18-xTiO2(x=0.10)堇青石基固溶體獲得最佳品質(zhì)因數(shù):Qf=69,800 GHz,?r=6.34,?f=-21 ppm/℃;而(1-x)Mg2Al4Si5O18-xTiO2(x=0.25)復(fù)合陶瓷獲得近零頻率溫度系數(shù):?f=-0.02 ppm/℃,?r=6.77,Qf=47,600 GHz。4)在(1-x)Mg2Al4Si5O18-xSCTiO3(SC=Sr、Ca;0≤x≤0.35)陶瓷的改性研究中,在0≤x≤0.10時(shí),形成堇青石固溶體;當(dāng)0.15≤x≤0.35時(shí),出現(xiàn)了液相SCAl2Si2O8長(zhǎng)石,此外,還有少量鈣鈦礦結(jié)構(gòu)的SCTiO3沉淀析出。最終,(1-x)Mg2Al4Si5O18-xSrTiO3(x=0.10)堇青石固溶體獲得最優(yōu)微波介電性能:εr=6.53,Qf=80,600 GHz,τf=-18 ppm/℃;液相CaAl2Si2O8擁有比SrAl2Si2O8更高的介電損耗。因此,(1-x)Mg2Al4Si5O18-xCaTiO3(x=0.05)堇青石固溶體微波介電性能為:εr=6.27,Qf=40,300 GHz,τf=-31 ppm/℃。
[Abstract]:In this paper, the microwave dielectric ceramics of cordierite (Mg2Al4Si5O18) are taken as the research object. The corresponding solutions are put forward for cordierite ceramics with narrow sintering temperature range, high sintering temperature, low quality factor QF and large resonant frequency temperature coefficient. The fields of study include: phase composition, sintering characteristics, micromorphology, lattice parameters and the order of arrangement of Si / Al, [(Si4Al2) O4] tetrahedron, and the effect of the structural changes of [(Si4Al2) O18] six-member ring on the microwave dielectric properties of [(Si4Al2) O18]. Cordierite based microwave dielectric materials with good properties were successfully prepared. The specific contents of this paper are as follows: 1) in the study of modification of (Mg1 X Lax) 2Al4Si5O18x (0 鈮，

本文編號(hào)：2065665