This study investigated electrical properties and microstructure of zinc oxide varistors containing MnO2, Cr2O3, V2O5 and TiO2. To this end, nanosize ZnO particles were synthesised by the polyacrylamide-gel method and doped with minor amounts of MnO2 (0.5 mol-%), Cr2O3 (0.5 mol-%), V2O5 (2 mol-%) and TiO2 in the range of 2–15 mol-%. The prepared samples sintered at 1050°C in air for 2 h. It was observed that TiO2 promoted grain growth of ZnO particles. X-ray examination showed hexagonal ZnO structure as a main phase and Zn2TiO4 and ZnV2O4 as minor secondary phases. The nonlinear coefficient and threshold voltage of the prepared samples were in the range of 3.3–7.9 and 1120–4700 V cm−1 respectively, in which both of them increased with increase in TiO2 content. Among the prepared samples, the varistor with 15 mol-% TiO2 exhibited the best performance in terms of nonlinearity. The nonlinear electrical behaviour was explained by theory of formation of the potential barriers at grain boundaries.
LiuT-T, WangM-H, ZhangH-P, Sol–gel synthesis of doped nanocrystalline ZnO powders using xanthan gum and varistor properties study. J Mater Sci Mater Electron. 2015;26:9056–9062. doi: 10.1007/s10854-015-3590-2
2.
WangM-H, ChenT, ZhangB.Synthesis of monodisperse ZnO nanostructures via a solvent extraction route and its use in varistor ceramics. J Mater Sci Mater Electron. 2015;26:5653–5657. doi: 10.1007/s10854-015-3115-z
3.
ChenG-h, LiJ-l, ChenX, Sintering temperature dependence of varistor properties and impedance spectroscopy behavior in ZnO based varistor ceramics. J Mater Sci Mater Electron. 2015;26:2389–2396. doi: 10.1007/s10854-015-2696-x
4.
FanJ, PoosimmaP, FreerR.Phase development in ZnO varistors. Adv Appl Ceram. 2015;114:14–17. doi: 10.1179/1743676114Y.0000000179
5.
KhafagyA-MH, El-RabaieSM, DawoudMT, Microhardness, microstructure and electrical properties of ZVM ceramics. J Adv Ceram. 2014;3(4):287–296. doi: 10.1007/s40145-014-0120-2
6.
SantosMRC, BuenoPR, LongoE, Effect of oxidizing and reducing atmospheres on the electrical properties of dense SnO2-based varistors. J Eur Ceram Soc. 2001;21:161–167. doi: 10.1016/S0955-2219(00)00177-1
7.
NahmCW.Varistor characteristics of ZnO/V2O5/MnO2/Nb2O5 semiconducting ceramics with Tb4O7 addition. J Mater Sci: Mater Electron. 2015;26:4144–4151.
8.
PillaiSC, KellyJM, McCormackDE, Effect of step sintering on breakdown voltage of varistors prepared from nanomaterials by sol gel route. Adv Appl Ceram. 2006;105:158–160. doi: 10.1179/174367606X110189
9.
KuwabaraM.Innovative nanocrystal-based technologies for ceramic devices with novel electronic functions. J Adv Ceram. 2012;1(2):79–88. doi: 10.1007/s40145-012-0016-y
10.
ChenG-h, LiJ-l, YangY, Microstructure and electrical properties of Dy2O3-doped ZnO–Bi2O3 based varistor ceramics. Mater Res Bull. 2014;50:141–147. doi: 10.1016/j.materresbull.2013.10.032
11.
ZhaoZ-Y, WangM-H, ZhangH-P.Microstructure and varistor properties of V-doped ZnO nanoparticles prepared by co-precipitation method. J Mater Sci Mater Electron. 2016;27:1777–1782. doi: 10.1007/s10854-015-3953-8
12.
RabaeiS, KhafargyAH.Mechanical, microstructure and electrical properties of ternary ZnO–V2O5–Mn3O4 varistor with sintering temperature. Bull Mater Sci. 2015;38:1–5. doi: 10.1007/s12034-014-0796-5
13.
Moghri MoazzenMA, BorgheiSM, TaleshiF.Change in the morphology of ZnO nanoparticles upon changing the reactant concentration. Appl Nanosci. 2013;3:295–302. doi: 10.1007/s13204-012-0147-z
14.
SinghaiM, ChhabraV, KangP, Synthesis of ZnO nanoparticles for varistor application using Zn-substituted aerosol ot microemulsion. Mater Res Bull. 1997;32:239–247. doi: 10.1016/S0025-5408(96)00175-4
15.
Maleki ShahrakiM, BahrevarMA, MirghafourianSMS.The effect of TiO2 addition on microstructure and electrical properties of SnO varistors prepared from nanomaterials. Ceram Int. 2015;41:6920–6924. doi: 10.1016/j.ceramint.2015.01.146
16.
VimalaK, SambaK, MohanY.Controlled silver nanoparticles synthesis in semi-hydrogel networks of poly(acrylamide) and carbohydrates: a rational methodology for antibacterial applicationm Carbohydr. Polym. 2009;75:463–471.
17.
TangJ, YangX.An one-pot epitaxial growth method to synthesize cactus-like ZnO. Mater Lett. 2006;60:3487–3491. doi: 10.1016/j.matlet.2006.03.037
18.
YangaL, DongaS, SunaJ-H.Microwave-assisted preparation, characterization and photocatalytic properties of a dumbbell-shaped ZnO photocatalyst. J Hazard Mater. 2010;179:438–443. doi: 10.1016/j.jhazmat.2010.03.023
19.
ThabitHA, KabirNA.The study of X-ray efect on structural, morphology and optical properties of ZnO nanopowder. Nucl Instrum Methods Phys Res Sect B. 2018;436:278–284. doi: 10.1016/j.nimb.2018.10.012
20.
MirzayiM, HekmatshoarMH.Effect of V2O5 on electrical and microstructural properties of ZnO ceramics. Phys B. 2013;414:50–55. doi: 10.1016/j.physb.2013.01.020
21.
MakovecD, KolarD, TronteljM.Sintering and microstructural development of metal oxide varistor ceramics. Mater Res Bull. 1993;28:803–811. doi: 10.1016/0025-5408(93)90021-5
22.
NahmCW.Microstructure and electrical characteristics of MnTa-doped ZnO–V2O5-ceramics with sintering. J Alloys Compd. 2010;505:657–660. doi: 10.1016/j.jallcom.2010.06.102
23.
BuenoPR, VarelaJA, LongoE.Sno2, ZnO and related polycrystalline compound semiconductors: An overview and review on the voltage-dependent resistance (non-ohmic) feature. J Eur Ceram Soc. 2008;28:505–529. doi: 10.1016/j.jeurceramsoc.2007.06.011
24.
MoulsonAJ, HerbertJM.Electroceramics. 2nd ed. West Sussex, England: John Wiley & Sons; 2003.
25.
HouabesM, BernikS, TalhiC, The effect of aluminium oxide on the residual voltage of ZnO varistors. Ceram Int. 2005;31:783–789. doi: 10.1016/j.ceramint.2004.09.004
26.
GuptaTK, CarlsonWG.A grain-boundary defect model for instability/stability of a ZnO varistor. J Mater Sci. 1985;20:3487–3500. doi: 10.1007/BF01113755
27.
BidadiH, HasanliSM, HekmatshoarH, Temperature dependence of electrophysical characteristics of zinc oxide based varistors. Vacuum. 2010;84:1232–1235. doi: 10.1016/j.vacuum.2009.10.031
