•The secret to cool bodies and glazes is a lot of testing.
•The secret to know what to test is material and chemistry knowledge.
•The secret to learning from testing is documentation.
•The place to test, do the chemistry and document is an account at https://insight-live.com
•The place to get the knowledge is https://digitalfire.com
TGA - TGA
This test procedure was employed in the Foresight Ceramic Database and now is available for those having an account at Insight-Live.com.
Accumulating test data using the variables defined in these procedures enables us to create tools that enable you to compare the physical properties of materials and recipes.
This test measures weight changes in a material as it is heated and provides a convenient method for characterizing the decomposition process in inorganics. The test results are plotted on an x-y graph as temperature vs. weight. For example, calcium oxalate monohydrate, a standard material often used to verify TGA performance, exhibits three weight losses with temperatures in an inert atmosphere that appear to represent the loss of water, carbon monoxide and carbon dioxide via the process:
CaC2O4 . H2O --> CaC2O4 --> CaCO3 --> CaO
Absolute confirmation of conclusions can be done by analyzing the gaseous by-products as there evolve. Also, if a mass spectrometry (MS) curve is overlaid onto a TGA plot a more complete understanding of the decomposition process can be had. In the case of the above material, for example, the MS curve shows that the decomposition process is more complex than shown by the TGA alone. The second weight loss produces both CO and CO2. This can be explained based on further reaction of some of the CO initially formed into CO2 and pure C (this is confirmed by the presence of grey residue in the material after heading).
VAL - Value (V)
The result of the variables need to be compiled
TGA Analysis graph with overlaid mass spectrometry curve
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By Tony Hansen