Influence of P2O5 and SiO2 Addition on the Phase, Microstructure, and Electrical Properties of KNbO3

  • S. UllahEmail author
  • I. Ullah
  • Y. Iqbal
  • A. Manan
  • S. Ali
  • A. Khan
Research paper
Part of the following topical collections:
  1. Physics


In this contribution, the effect of \(\hbox {P}_{2}\hbox {O}_{5}\) and \(\hbox {SiO}_{2}\) addition on the phase, microstructure, and electrical properties of \(\hbox {KNbO}_{3}\) was studied. Sample powders with the general formula \((1-x)\hbox {KNbO}_{3}\cdot x\hbox {P}_{2}\hbox {O}_{5}\,(x = 0.03, 0.05)\) and \((1-x)\hbox {KNbO}_{3}\cdot x\hbox {SiO}_{2}\,(x = 0.1)\) were prepared via mixed-oxide route. The thermal behavior of the mixed-milled powder was investigated by thermogravimetry and differential thermal analysis which revealed an overall weight loss of 33.4 wt % in the temperature range of \(30\le T \le 1200\,^\circ\)C and crystallization exotherm occurring at about 795 °C. The present results indicated that \(\hbox {P}_{2}\hbox {O}_{5}\) acted as a sintering aid and lowered the sintering temperature by about 30 °C and promoted densification of \(\hbox {KNbO}_{3}\). Sample compositions at various stages of processing were characterized using X-ray diffraction. Samples sintered at \(T \le\) 1020 °C revealed mainly \(\hbox {KNbO}_{3}\) together with a couple of low-intensity \(\hbox {K}_{3}\hbox {NbO}_{4}\) peaks as a secondary phase. The scanning electron micrographs of \((1-x)\hbox {KNbO}_{3}\cdot x\hbox {SiO}_{2}\,(x = 0.1)\) samples showed a slight increase in the average grain size from 3.76 ± 0.37 to 3.86 ± 0.74 \(\upmu\)m with an increase in sintering temperature from 1000 to 1020 °C. Strong variations in dielectric constant and loss tangent were observed due to \(\hbox {P}_{2}\hbox {O}_{5}\) and \(\hbox {SiO}_{2}\) addition as well as frequency of the applied AC signals.


Phase Microstructure Sintering TG/DTA Weight loss Potassium niobate 



Authors greatly acknowledge the financial support from the Higher Education Commission (HEC) of Pakistan and laboratory support extended by MRL, Department of Physics, University of Peshawar, Pakistan.


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Copyright information

© Shiraz University 2018

Authors and Affiliations

  1. 1.Materials Research Laboratory , Department of PhysicsUniversity of PeshawarPeshawarPakistan
  2. 2.Department of PhysicsGomal UniversityDera Ismail KhanPakistan
  3. 3.Department of PhysicsUniversity of Science and TechnologyBannuPakistan
  4. 4.Center of Excellence in Solid State PhysicsUniversity of the PunjabLahorePakistan

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