Ba6-xLa8+2x/3Ti18O54陶瓷體之備製及其微波特性

Abstract

本論文研究之主題，係以固態反應法及溶膠凝膠法，備製Ba6-xLa8+2x/3 Ti18O54陶瓷體。藉由改變不同x值、煆燒溫度及燒結溫度三種製程條件， 研究陶瓷體的微結構與微波性質之間的關係，以其能備製出未來無線通訊 中所要求之介電共振器。其中x值由1.5~3.0，固態反應法之煆燒溫度 從1000℃~1100℃/4h，溶膠凝膠法之RTA溫度由1000~1200℃/5min，兩方 法之燒結溫度皆在1250℃~1350℃/4h。在本研究中發現不論以固態反應法 或溶膠凝膠法，其生成單相固溶體的x值範圍皆在1.5~2.1之間。在此x值 之外會產生La4Ti9O24第二相。此外這兩種製程所得之塊材密度會隨著x值 增加而下降。在微波性質方面，固態反應法所製得的陶瓷體較好的微波性 質為x=1.8、1000℃煆燒4h、1300℃燒結4h，其微波性質k=75、Q×f=4460 、tf=+47ppm/℃。而以溶膠凝膠法所備製的陶瓷體中，tf最低為x=2.4 、1100℃RTA/5min、1350℃燒結4h，其微波性質k=64、Q×f=1850、 tf=+38ppm/℃。 A series of barium lathanum titanate ceramics Ba6-xLa8+2x/3Ti18 O54 were fabricated by solid state reaction and sol-gel techniques with various x values,calcination and sintering temperatures.The range of variations are (1)1.5~3.0 for x values (2)1000℃~1100℃/4h for calcination temperature (3)1000℃~1200 ℃/5min for RTA temperatures (4)1250~1350℃/4h for sintering temperatures.The microwave characteristics and microstructure of these ceramics have been studied. In this study,we find that single phases of the solid solutions were obtained in the range of by both solid state reaction and sol-gel techniques .On the outer sides of solid solutions,La4Ti9O24 appeared as the second phase in both solid state reaction and sol-gel techniques.The densities of Ba6-xLa8+2x/3Ti18O54 ceramics decrease with the increase of the x values.Good quality Ba6-xLa8+2x/3Ti18O54 ceramics were obtained by solid state reaction technique at x=1.8,calcined at 1000℃and sintering at 1300℃.The dielectric constant of the ceramics is 75,Q×f up to 4460 at 3 Ghz and tf around +47 ppm/℃.In the other hand,ceramics with k=64,Q×f=1850 and tf=+38ppm/℃were obtained by sol-gel technique after RTA at 1100℃/5min and sintering at 1350℃/4h.