Investigation of PTCR characteristics in Nb2O5-doped BaTiO3-based chip-type ceramics prepared by reduction sintering-reoxidation method

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040047
Author(s):  
Xuxin Cheng ◽  
Xiaoming Chen ◽  
Haining Cui ◽  
Yuxin Wang ◽  
Chao Xiong

This study investigates the influence of sintering conditions on electrical properties and positive temperature coefficient of resistance (PTCR) of [Formula: see text] (BTNO) ceramics, fired at [Formula: see text]C for different times from 1 to 6 h in a reducing atmosphere and reoxidised within the temperature range of [Formula: see text]–[Formula: see text]C for 1 h. The results showed that the room-temperature (RT) resistance and the resistance jump of the multilayer BTNO ceramics decreased with an increase in the firing time. Furthermore, the RT resistance of the BTNO samples gradually increased at first and then rapidly increased with increasing reoxidation temperature. In addition, the influence of sintering times on the microstructure of ceramics was also investigated.

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840071
Author(s):  
Xuxin Cheng ◽  
Xiaoming Chen ◽  
Xiaoxia Li ◽  
Haining Cui ◽  
Chao Xiong

In this work, we investigate the influences of Ba/Ti ratio and sintering conditions on the characteristics of positive temperature coefficient of resistance (PTCR) and electrical properties of Ba[Formula: see text](Ti[Formula: see text]Nb[Formula: see text])O3 (BTN) ceramics. The ceramics were fired at 1190[Formula: see text]C for 0.5–6.0 h in a reducing atmosphere and then reoxidized at 600–650[Formula: see text]C for 0–8 h. The Ba/Ti ratio [Formula: see text] affected the electrical properties and PTCR effect of the BTN specimens. The room-temperature (RT) resistance of the BTN samples initially decreased [Formula: see text] and then increased [Formula: see text] as the Ba/Ti ratio increased. Moreover, BTN ceramics exhibit a pronounced PTCR effect, with a resistance jump greater by 3.0 orders of magnitude and a low 0.1 [Formula: see text] RT resistance at a low reoxidation temperature of 600[Formula: see text]C after sintering under a reducing atmosphere. Furthermore, the average sample grain size increased along with the Ba/Ti ratio. In addition, the influence of the sintering time and the reoxidation time on the electrical properties and the PTCR effect were also investigated.


2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744061
Author(s):  
Xuxin Cheng ◽  
Xiaoxia Li ◽  
Xiaoming Chen ◽  
Haining Cui

This study investigates the influence of dopant content and firing conditions on electrical properties and positive temperature coefficient of resistance (PTCR) effect of Ba[Formula: see text](Ti[Formula: see text]Nb[Formula: see text]O3 (BTN) ceramics sintered at different temperatures from 1070[Formula: see text]C to 1220[Formula: see text]C for 2 h in a reducing atmosphere and reoxidized within the temperature range of 600[Formula: see text]–[Formula: see text]750[Formula: see text]C for 0.5[Formula: see text]–[Formula: see text]8 h. The results indicate that the room-temperature (RT) resistance of the laminated BTN specimens initially decreased and then increased as a function of the dopant concentration. Moreover, the resistance jump exhibited a contrasting tendency. Furthermore, the RT resistance of the BTN samples rapidly decreased at first and then gradually decreased with increasing sintering temperature. Meanwhile, the resistance jump of the samples increased first and then decreased. In addition, the influence of reoxidation times on the PTCR characteristics of ceramics was investigated.


2011 ◽  
Vol 415-417 ◽  
pp. 1032-1037
Author(s):  
Xu Xin Cheng ◽  
Dong Xiang Zhou ◽  
Qiu Yun Fu ◽  
Shu Ping Gong

Electrical properties, positive temperature coefficient of resistivity (PTCR), and microstructures of (Bam-0.007Sm0.007)TiO3(BST) with different Ba-site/Ti-site (A/B) ratio sintered in a reducing atmosphere and reoxidized in air are investigated. The results reveal that the room temperature resistivity of the semiconducting BST ceramics first decreases and then increases with increasing of A/B ratio (m), particularly when m is equal to 1.006, the semiconducting BST ceramics which have been sintered in a reducing atmosphere and reoxidized at 800°C exhibit significant PTCR effect with a resistance jumping ratio of 3 orders magnitude, and achieve a lower room temperature resisitivity of 80.8 Ω∙cm, in addition, the grain size distribution of the Ti-excess specimens is much better than that of the Ba-excess ones.


2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744060
Author(s):  
Xuxin Cheng ◽  
Haining Cui ◽  
Xiaoxia Li ◽  
Wen Deng

The influence of Nb2O5-doped concentration on the positive temperature coefficient of resistance (PTCR) effect, electrical properties and microdefects of (Ba[Formula: see text]Sr[Formula: see text])(TiNb[Formula: see text])O3 (BSTN) ceramics were investigated. Firing was conducted at 1350[Formula: see text]C for 2 h in air. The donor-doped content affected the electrical properties, PTCR effect and formation of the microdefect type of the BSTN samples. The room temperature resistivity of the BSTN specimens first decreased and then increased with increasing donor-doped content in the range of 0.2 mol.% Nb[Formula: see text] to 0.5 mol.% Nb[Formula: see text]. Moreover, the information on microdefects in BSTN ceramics was demonstrated by coincidence Doppler broadening spectrum. The influence of the defects on the PTCR characteristics of the ceramics was also revealed.


2014 ◽  
Vol 881-883 ◽  
pp. 1031-1034
Author(s):  
Xu Xin Cheng ◽  
Dong Xiang Zhou ◽  
Zhao Xiong Zhao ◽  
Qiu Yun Fu

Positive temperature coefficient of resistivity (PTCR) effect and electrical properties of (Ban-xSmx)TiO3(BSMT ) samples with different Ba-site/Ti-site ratio (n) and various concentration of the donor-doped Sm3+(x) sintered in a reducing atmosphere and reoxidized in air are investigated. The results show that the room temperature resistivity (ρRT) of the semiconducting BSMT ceramics first decreases and then increases with increasing of concentration of the donor-doped Sm3+, especially whenxis 0.005 mol, the ρRTof the BSMT ceramics is the lowest. Moreover, the ρRTof the Ba-excess BSMT (n= 1.01) specimens reoxidized at 800 oC for 1 h after sintering at 1270 °C for 30 min in a reducing atmosphere is lower than the Ti-excess ones (n= 0.99), in addition, the ρRTof the BSMT specimens increases with an increase of both sintering temperature and reoxidized time.


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