Hello everyone,
I'm currently doing some DTA analysis on two phases of the same ceramic material, one is fully crystalline and the other fully amorphous.
When I work with the crystalline one I have a melting peak, with a clear area I can integrate if I want to.
But when I'm working with the amorphous one, I don't have a peak anymore but more like a transition, with no distinct area (similar to a reversed glass transition in a way).
Why don't I have a proper melting peak on my amorphous material ?
The same heating rates have been used, with really closed mass for the samples.
Thank you for your help,
Julien
The main difference between amorphous and crystalline states of the material is precisely that the amorphous state does not have a melting point. So it goes without saying that your amorphous sample will not show a peak on the DTA curve.
Isn't there supposed to be a melting point due to the cold crystallization occurring right after the glass transition? From every DTA of glasses I have looked so far in the literature, there is always a melting area even for initial 100% amorphous materials, at similar heating rates
Crystallization of silicate glasses occurs at temperatures significantly exceeding their Tg points. If for most silicate glasses the Tg temperature is about 500°C, then crystallization begins at least 800°C, and in some cases at 1000-1200°C. In addition, there are silicate glasses that do not crystallize at any temperatures.
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