|Monthly Tech-Tip |
Information found at http://www.reimbold-und-strick.de/
This test is important in the assessment of materials for use in glass ceramics. The heating microscope describes the melting of frits during the heating process. A cube of 3x3x3 mm is pressed of fine ground frit, is heated at 30 - 40°C/min (others specify 10°C/min) to 1400C. During this process characteristics of the silhouette are recorded. These observations can be interpreted differently by different people.
For frits, it is more common to interpret a glass transition (transformation) point and softening point by interpreting the curve produced by a dilatometer.
At this temperature the height of the cylinder shrinks by 5%, also referred to as transformation point.EP - Softening Point (V)
The beginning of softening: The temperature at which the corners show rounding.K - Ball Point (V)
At this temperature the silhouette is similar to a sphere.HK - Half-ball Point (V)
Temperature at which the height is half of the base. Interpreted at the melting temperature.F - Liquid Point (V)
The sample has melted to 1/3 of its original height.
Frit Softening Point
In ceramics, this is the temperature at which a glaze or glass begins to flow, ceasing to exhibit the properties of a solid.
Frit Melting Range (C)
Glass Transition Temperature
In ceramic glasses (usually frits) the temperature at which the hard brittle state of the glass changes to the rubber-like state that precedes softening and melting
Frit Fusibility Test
Test conducted primarily on materials use to make bodies or glazes.
|By Tony Hansen|
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