Microwave Properties in BaO-TiO2 System Added by ZrO2 and WO3

2012 ◽  
Vol 512-515 ◽  
pp. 1155-1159 ◽  
Author(s):  
Xin Ye Yang ◽  
Xiao Hui Wang ◽  
An Ji ◽  
Long Tu Li

Both BaTi4O9 and Ba2Ti9O20 have the best microwave properties among many compounds in BaO-TiO2 system. The microwave performance of the ceramics in BaO-TiO2 system, which were prepared by conventional solid state method, was investigated in this paper. The study indicates that the (Ti,Zr)/Ba ratio has a great effect on the dielectric properties of the ceramic due to different BaTi4O9/Ba2Ti9O20 ratio. The pure BaTi4O9 ceramic exhibits the most outstanding microwave properties, with εr=35.55 and Q×f=43300GHz. On the contrary, the dielectric property of the pure Ba2Ti9O20 ceramic was not good enough, which should be doped with some additive additions. WO3 was incorporated into the system and the sintering temperature was adjusted to improve the microwave dielectric property. The Q×f was increased to 38000GHz by adding 1.35mol% WO3 due to the formation of a little BaWO4 phase. When sintered at a higher temperature (1380°C), the BaO-TiO2 system ceramic has εr =37.04 and Q×f =44874GHz.

2008 ◽  
Vol 368-372 ◽  
pp. 179-182
Author(s):  
Zong Chi Liu ◽  
Dong Xiang Zhou ◽  
Shu Ping Gong

The effects of CuO-MoO3 addition on the sintering behavior and microwave dielectric properties of ZnO-TiO2 ceramics were investigated. ZnO-TiO2 ceramics were prepared with conventional solid-state method and sintered at temperatures from 850 to 1050 °C. The sintering temperature of ZnO-TiO2 ceramics with CuO-MoO3 addition could be effectively reduced to 950 °C due to the liquid phase effects resulting from the additives. A proper amount of CuO-MoO3 addition could effectively improve the densification and microwave dielectric properties of ZnO-TiO2 ceramics. ZnO-TiO2 ceramics with 3 wt% addition sintered at 950 °C for 4 h exhibited better microwave dielectric properties as follows: εr of 26.8, a Q×f value of 16780 GHz at 5.42 GHz, and a τ f value of +34.7 ppm/°C.


2010 ◽  
Vol 434-435 ◽  
pp. 235-239
Author(s):  
Bo Li ◽  
Xiao Hua Zhou ◽  
Shu Ren Zhang ◽  
Long Cheng Xiang

The microwave properties and microstructures of (ZnMg)TiO3-based dielectric prepared by conventional solid-state method were investigated as functions of CaTiO3 and CaO-B2O3-SiO2 additions. The effects of CaTiO3 on the crystal phase and the evolution of microstructure of (Zn0.65Mg0.35)TiO3 were studied. The result indicated that CaTiO3 secondary phase coexists with (ZnMg)TiO3 main phase in the ZMT-CT ceramics, which confirmed by EDS analysis. Because of CaTiO3 with large τf value (τf = 800 ppm/°C), the temperature coefficient of resonant frequency (τf) of ZMT-CT with biphasic structure was adjusted to near zero value. The microwave properties of (Zn0.65Mg0.35)TiO3 ceramics doped with 5wt% CaTiO3 sintered at 1150°C were ε ≈ 24, τf ≈ ±10 ppm/°C, Q×f > 45,000 GHz. Further, it was found that the CaO-B2O3-SiO2 additive could successfully reduce the sintering temperature of (Zn0.65Mg0.35)TiO3–CaTiO3 ceramics from 1150 to 950°C, and significantly improve the densification of this system, which were densified below 1000°C. This was due to the formation of liquid phases during the sintering observed by SEM. The (Zn0.65Mg0.35)TiO3–0.05CaTiO3 dielectrics with 1 wt% CaO-B2O3-SiO2 sintered at 950~1000°C exhibited the optimum microwave properties: ε ≈ 22, Q×f ≈ 20,000 GHz and τf ≈ ±10 ppm/°C.


RSC Advances ◽  
2021 ◽  
Vol 11 (50) ◽  
pp. 31631-31640
Author(s):  
Fatasya Izreen Hanim Alias ◽  
Rozilah Rajmi ◽  
Mohd Fauzi Maulud ◽  
Zakiah Mohamed

In this paper, Sr2Ni1−xZnxTeO6 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) double perovskite compounds were synthesised by the conventional solid-state method, and the structural, optical and dielectric properties were investigated.


2016 ◽  
Vol 840 ◽  
pp. 8-13
Author(s):  
Hidayani Jaafar ◽  
Zainal Arifin Ahmad ◽  
Mohd Fadzil Ain

The structure and dielectric properties of Barium Zinc Tantalate (BZT) doped by copper oxide (CuO) with a variety of values of mol% doping from 0, 0.1, 0.25, 1.0, 1.5 and 2.5 were prepared using a solid state method. The addition of CuO did not disturb the 1:2 ordering structure of the BZT ceramic. The grain size increased when the addition of doping increased. A small amount of doping elements increased the relative density. The dielectric constant (ɛr) value of the BZT significantly improved with the addition of the CuO for the specimens sintered at 1250°C and it could be explained by the increase of the relative density. The tan δ of the CuO doped with BZT ceramics is lower than pure BZT ceramics, and decreases as the CuO content increases. Meanwhile, for the percentage of bandwidth (%BW) it is shown that the best result is produced when it is doped with 0.25 mol% CuO and sintered at 1250°C. The best microwave dielectric properties obtained were ɛr=70.28, tan δ = 0.024, %BW = 7.83 which occurred for the 0.25 mol% doped CuO and when sintered at 1250°C/4 h.


2012 ◽  
Vol 499 ◽  
pp. 178-182
Author(s):  
Yi Shan Jiang ◽  
Ying Zi Wang ◽  
Ya Ming Chen ◽  
Yun Long Yue ◽  
Hai Tao Wu

Microwave dielectric ceramics of Mg4Nb2O9were prepared by the solid-state method and their microwave dielectric properties and microstructure were investigated in this study. The sintering ability and microwave dielectric properties of Mg4Nb2O9ceramics were studied under various sintering temperatures ranging from 1200°C to 1350°C. As the sintering temperature increased from 1200°C to 1350°C, the density values, the εr values and the Q·ƒ values increased and saturated at 1350°C.The ƒ values were ranged from -48.7 to -57.8 ppm/°C. Due to the increased density and appropriate grain growth the Mg4Nb2O9ceramics sintered at 1350°C had the excellent microwave dielectric properties of εr=12.3, Q·ƒ =108,000GHz and ƒ=-55.3ppm/°C.


2015 ◽  
Vol 1119 ◽  
pp. 451-455
Author(s):  
Yih Chien Chen ◽  
Chih Hung Li ◽  
Hua Xian Liu ◽  
Jing Yu Fu

The influence of sintering temperature on the microwave dielectric properties and microstructure of the (1-y)Nd0.96Yb0.04(Mg0.5Sn0.5)O3-yCa0.8Sr0.2TiO3 ceramic system were investigated with a view to their application in microwave devices. The (1-y)Nd0.96Yb0.04(Mg0.5Sn0.5)O3-yCa0.8Sr0.2TiO3 ceramic systems were prepared using the conventional solid-state method. The X-ray diffraction patterns of the (1-y)Nd0.96Yb0.04(Mg0.5Sn0.5)O3-yCa0.8Sr0.2TiO3 ceramic system shifted to higher angle as y increased. A dielectric constant of 38.2, a quality factor (Q×f) of 53,500 GHz, and a temperature coefficient of resonant frequency of-3 ppm/°Cwere obtained when the 0.4 Nd0.96Yb0.04(Mg0.5Sn0.5)O3–0.6Ca0.8Sr0.2TiO3 ceramic system was sintered at 1600 °C for 4h.


RSC Advances ◽  
2016 ◽  
Vol 6 (90) ◽  
pp. 86889-86903 ◽  
Author(s):  
H. L. Pan ◽  
Q. Q. Liu ◽  
Y. H. Zhang ◽  
H. T. Wu

Wolframite structure Zn1−xCoxZrNb2O8 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) ceramics were prepared by the conventional solid state method.


2013 ◽  
Vol 575-576 ◽  
pp. 91-94
Author(s):  
Xin You Huang ◽  
Mu Sheng Huang ◽  
Chun Hua Gao ◽  
Zhi Gang Chen

The influence of the BaSiO3 dopant on the dielectric properties of (Ba,Sr)TiO3(BST) capacitor ceramics was studied using conventional capacitor ceramics solid state method and XRD , SEM and other analytical methods. The results show that BaSiO3 doping can improve the sintering and microstructure of the capacitor ceramics. SEM study show that BaSiO3 doping can make grain grow uniformly and suppress the grain to grow up, and the structure of ceramics is compact with little pore. XRD study show that there is little SiO2 phase and little influence of BST lattice parameter when BaSiO3 doped amount is 3 mol%.The dielectric properties of BST ceramics doped with 3 mol% BaSiO3 are as follows: dielectric constant (εr) of 1792, which is a little higher than undoped BST ceramics, tanδ of 1%, which is decreased 7.24% compared with undoped BST ceramics, and the sintering temperature decreases 40°C.


2014 ◽  
Vol 1035 ◽  
pp. 155-160 ◽  
Author(s):  
Sheng Jie Yang ◽  
Feng Gao ◽  
Meng Jie Qin ◽  
Chao Chao Zhang ◽  
Xi Xi Huang

Sr3Ti2O7ceramics with pure Ruddlesden-Popper phase (RP) were synthesized by conventional solid state method. The influences of the Bi2O3addition, the calcination temperature, and the sintering temperature on the phase transition were studied. The results showed that for the samples without doping Bi2O3, the main phase of calcined powders is Sr3Ti2O7, but pure Sr3Ti2O7phase cannot be obtained in the sintered ceramics because of the Sr3Ti2O7decomposition. For the samples doping with Bi2O3, although the main phase of the calcined powder is SrTiO3, the single RP phase Sr3Ti2O7can be obtained after sintering, which should be attributed to the formation of Sr3Bi2O6phase during calcination stage. Bi2O3addition is beneficial to the formation of the Sr3Ti2O7RP phase.


2013 ◽  
Vol 677 ◽  
pp. 153-156 ◽  
Author(s):  
Cheng Hsing Hsu ◽  
Wen Shiush Chen ◽  
Hsin Han Tung ◽  
Pai Chuan Yang ◽  
Jenn Sen Lin

Microwave dielectric properties of BaTi5O11ceramics prepared by solid-state method with various calcining temperatures and sintering temperatures have been discussed. The εrvalue of 42.8, the Q×f value of 44,000 GHz, and the τfvalue of 42.4 ppm/oC were obtained for BaTi5O11ceramics sintering at 1100oC for 4 h. BaTi5O11is proposed as a suitable material candidate for application in high selective microwave ceramic passive components.


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