I am synthesizing double-perovskite material. Sr2MgMoO6. After synthesizing, in the calcination process, after 700 degrees Celsius, the sample is sticking on the alumina boat.
I tried different chelating agents and fuels, i.e. citric acid, EDTA, and glycine.
But the same thing is only happening.
Up to 600 degrees Celsius, the sample is fine (White colour).
After that only problem starts.
In the literature, no one has reported this kind of issue.
Please help to solve this issue.
There are several potential factors contributing to the sample sticking on the alumina boat during the calcination process. These may include inadequate surface preparation of the alumina boat, excessive moisture content in the sample, or improper temperature control during the calcination process.
R. Stanley You may actually have a chemical reaction between the alumina and your oxide material. Try switching to a Pt boat. Or keep the temperature below 6000C.
R. Stanley As Alan F Rawle says, it's likely that you have a chemical reaction with the boat.
Melting point of MoO3 is ~800 degC. It is likely that the addition of two basic oxides (three if you include the alumina) will generate some liquid phase at 700 degC (not that far down) because of eutectic melting. Once you have a liquid, any possible reactions will happen much faster and may include the alumina. Pt should solve the problem. Most boats made of oxides will be "at risk", although you might try yttria-stabilized ZrO2.