When the ice melts out, a second phase other than water and ice appears.
I believe similar phenomena are occurring in ceramic firing.
When the ceramic is baking,
Do not raise the temperature until it becomes liquid.
Although it is solid, there are some components close to the melting point.
It turns into a liquid and becomes solid again as it becomes frozen.
When the liquid component becomes solid
Oxidation becomes insufficient,
It is the idea to disturb the insulation properties.
In order not to make this liquid component,
Firing at low temperature,
It is firing at high temperature to oxidize the resulting liquid component.
This is because
When sintering at 700 degrees, leakage current of SrBi2Ta2O9 (SBT) film is small,
Even though it is even 800 degrees,
The fact that if the firing is done at 750 degrees, the leakage current of SBT increases.
It can be explained.
For the crystallization of bismuth layered ferroelectric SrBi 2Ta2O9,
Oxygen partial pressure is related greatly.
With less oxygen, even at 700 degrees or less
To crystallize.
However, as leakage characteristics at this time
There is not enough consideration.
Bake the SBT thin film made at 700 degrees again at 800 degrees,
Electrochemically Etching out fine components,
in a gas or liquid that promotes oxidation of trace components Reoxidize.
Ultrasonic cleaning in nitric acid or sulfuric acid.
It may unexpectedly let the fine component rinse out.
The SBT film made by baking at 800 degrees,
It has no leaks and it has hydrogen resistance.
This will be the original strength originally possessed by the SBT crystal.
Looking at it as a films, I can not use it,
Due to the fine components of the substrate interface and particle interface,
Almost, as expected.
It is important that the fine components as bismuth poor pyroclore crystals must be made or be replaced.
Because that fine bismuth poor crystals can reduce the SBT insulator crystal around those to topological insulator.
理工学、経済、実験、電池に関するコラムニスト。