燒結(jié)性能和介電性能的影響
(南京工業(yè)大學 材料科學與工程學院，南京 210009)
摘 要: 采用傳統(tǒng)固相反應法制備Ba6−3x(La1−mBim)8+2x(Ti0.95Zr0.05)18O54(x=2/3)微波介質(zhì)陶瓷，研究Bi摻雜對Ba6−3xLa8+2x(Ti0.95Zr0.05)18O54(x=2/3)陶瓷的燒結(jié)性能、微觀結(jié)構(gòu)以及介電性能的影響。結(jié)果表明：當0＜m＜0.4時，Bi3+取代A1位的La3+生成單相類鎢青銅型固溶體；當Bi3+的摻雜量超過這個范圍時，La0.176Bi0.824O1.5作為第二相出現(xiàn)在固溶體中；Bi3+的摻入使Ba6−3xLa8+2x(Ti0.95Zr0.05)18O54(x=2/3)陶瓷的燒結(jié)溫度從1 400 ℃降低到1 300 ℃，同時，其介電常數(shù)大幅度提高，諧振頻率溫度系數(shù)減小，但品質(zhì)因數(shù)急劇減小；當m=0.05時，1 350 ℃下保溫 2 h燒結(jié)獲得的陶瓷具有微波介電性能，εr=88.63，Q·f=4 395 GHz，τf=6.25×10−6/℃。
關(guān)鍵字: 介電性能；Bi摻雜；微波介質(zhì)陶瓷；類鎢青銅結(jié)構(gòu)
（College of Materials Science and Engineering, Nanjing University of Technology, Nanjing 210009, China）
Abstract:The sintering properties, microstructures and dielectric characteristics of Ba6−3x(La1−mBim)8+2x(Ti0.95Zr0.05)18O54 (x=2/3) microwave dielectric ceramics prepared by conventional solid-state route were studied. The results show that Bi3+ replaced La3+ into A1 rhombic sites and a single-phase solid solution with tungstenbronze-like structure formed in the range of 0＜m＜0.4. When Bi3+ content exceeds this range, a second phase of La0.176Bi0.824O1.5 appears in the solid solution. Bi doping can lower the sintering temperature of Ba6−3x(La1−mBim)8+2x(Ti0.95Zr0.05)18O54(x=2/3) ceramics from 1 400 ℃ to 1 300 ℃, while a significant improvement of dielectric constant is achieved. The temperature coefficient of resonant frequency (τf) decreases, and the quality factor (Q·f) rapidly decreases. When m=0.05, the optimal microwave dielectric characteristics are achieved as εr=88.63, Q·f=4 395 GHz, τf=6.25×10−6/℃.
Key words: dielectric property; Bi doping; microwave dielectric ceramics; tungstenbronze-like structure
