The synthezied solid state reaction method that PbO is compositon in compound such as 3Pb(MgNb)O3 was sinter about 1000-1100 C while melting point PbO at 850 C.
melting point of PbO is 850C, but it is much higher for PMN. One PMN is formed near 800C then you are sintering PMN not PbO
I synthezied PMN-PT by calcination at 850 C for 4h which it had pyrochlore phase. If reduce temperature at 800 C, how many time for cacine?
Prepare it by columbite method. i.e first prepare colombite then add PbO to get PMN-PT. You will get perovskite. If you are directly mixing PbO, MgO, TiO2 and Nb2O5 then it will be a mixture of perovskite and pyrochlore. If you want to know how to prepare colombite please contact me at [email protected]
I will explain the process.
As recommended by Gurvinderjit, you should use columbite method. Another important thing is to prevent lead loss during calcination even in this method. You will have to use a lead seal of the same mixture which you are going to use for calcination. Also it is advised to press the powder(mixture of MgNb2O6 and PbO) in to pellet and carry out calcination. You will have to cover you pellet with the same powder from all side and also keep it in a sealed cruicble(alumina /Pt). 900degree c is good enough temperature for calcination. If you still get a pyrochlore phase then you can add 2-5% excess PbO to compensate the lead loss.
Thank's Tarun Garg for recommended ,you means the sample powder have to press into a pellet before calcine. What's meaning "same powder" (PbO+MgO) cover the pellet ?
Then after calcine, Does the same pellet or grind to powder, compress it again for sinter process ?
After calcination, you will have to grind it into fine powder, press again and sinter it in the same way as you will do for calcination (i mean by putting proper lead seal)at 1100-1150 deg C for 4-6 hrs depending upon purity of your precursor powders
Proper lead seal means covering your pellet with your precursors mixture. Keep the pellet on an alumina disk. cover it with your precursors mixture of which your pellet is made of. Take an alumina crucible and keep it inverted over your pellet covered with powder. Also put some powder at the edges of inverted crucible to avoid lead loss. In this way your pellet would be calcined/sintered in a lead rich atmosphere.
Good luck!!
one question, calcine temperature at 900 c 5C/min this right and how much of time for calcine ?
It means that when you are doing sintering, the lead atmosphere is formed around your pellet. So chances of lead to come out from your pellet are less. Lead atmosphere is formed as it evaporates at high temperature (T>900C). Since your crucible is sealed, as explained by Garg, so it retains for quite some time.
Thanks to Tarun Garg and Gurvinderjit Singh. How did seal a crucible? PbO is melt in crucible,after sintering that can not remove melt from a crucible.
Donot put pure PbO, put your own calcined powder of PMN or otherwise PbZrO3 is best option. Remove top/bottom suface of sintered pellet by grinding or cutting
I used to download Gurvinderjit Singh paper publich.
What will studies about ferroelectric and piezoelectric properties?
What should be studies about ferroelectric and piezoelectric properties theory for dissertation and thesis?
How does calculate of dielectric loss , complex permittivity (real and imagine part) and Cole-Cole ?
Measure capacitance of your sample. from capacitance you can calculate the dielectric constant. The voltage current phase will give you loss.
please let me know which instrument you are using for these measurements.
To G"Sing and Garg , for sintering process, I use PbZrO3 cover sample, Should PbZrO3 come from seal PMN pellet in calcine process (which I calcine 850C) or new mix PbO +ZrO2 powder again ?
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