I'm working KNbO3 based materials..I have prepared my powder by solid state method and after calciantion at 850oC I'm pot milling my powder for 6h. I'm sintering my pellet at 1050oC/4h. If I increase my sintering temperature my sample is getting melt..If I sinter at 1050 I'm getting high dielectric loss around 4.37 at 100Hz..Is there any way to reduce the dielectric loss...
Dear Abhinay, Please find out the density of your sample and compare it with theoretical density (try to get more than 95%) . In order to get higher density, change the binder composition and uniformly mix it with your sample before making pallets. While sintering first evaporate the binder at 500-600 for 15 min and then go to your desired temperature. Try to keep a slow heating rate to avoid pore formation. In order to go high temperature and prevent melting try to cover your pallets in the KNbO3 calcined powder and then keep it for sintering.
Ashwani Tyagi thankq for your valuable suggestion..I'm following the above mentioned process but that is not helpful in my case....
Hi
In my view the dielectric loss and constants are based on the kind material we have. Electron density, polarization efect n all. If your material is given higher dielectric loss at 1050 means it may be in higly crystaline form i guess. Generally in amorphous nature loss tangent will be less. So do rapid sintering for your material. In rapid sintering chances of creating amorphous nature is more. Is degree of orderness is reduce in matel it may affect conductivity and simultaneously loss tangent.
Best
Dr. Arun
An alternating electric field on a dielectric causes a frequency dependence of the polarization and the polarizability. As long as the frequency of the applied electric field is low, the response of the dipole follows the field, However, if the frequency increases, the dielectric could no longer follow the electric field, and hence would experience a loss. Let us define a frequency ω_0, such that for the frequency of the applied field ωω_0. The relaxation time τ=(ω_0)^-1. The relaxation occurs due to the damping effect by the rigid environment in a solid dielectric.
The frequency dependent dielectric constant is complex. The loss factor tan (delta) is given by Im(dielectric function)/Re (dielectric function).For finite phase difference between the applied field and the displacement vector, the dielectric experiences a loss. If this is reduced loss can be reduced.
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