THERMAL SHOCK TESTING AT ETS
Thermal Shock is the name given to cracking as a result of rapid temperature change. Glass and ceramic objects are particularly vulnerable to this form of failure, due to their low toughness, low thermal conductivity and high thermal expansion coefficients. However they are used in many high temperature applications due to their high melting point.
Thermal shock occurs when a thermal gradient causes different parts of an object to expand by different amounts. This differential expansion can be understood in terms of stress or of strain, equivalently. At some point, this stress overcomes the strength of the material, causing a crack to form. If nothing stops this crack from propagating through the material, it will cause the objects structure to fail.
Thermal shock can be prevented by
- Reducing the thermal gradient seen by the object
- Changing its temperature more slowly
- Increasing the material's thermal conductivity
- Reducing the materials coefficient of thermal expansion
- Increasing its strength
- Deceasing its young's modulus
- Increasing its toughness by crack tip blunting i.e. plasticity or phase transformation crack deflection
We can programme any cycle to your product, examples of cycles we have put products through at ETS are:
- 1000 Hour low temperature storage test @ -65°C
- 1000 Cycles, 30 minutes dwell at each extreme -40°C to +125°C
- Temperature Cycling Test - 2000 Cycles
-40°C to +145°C
30 Second transition time
20 Minute dwell at each extreme - Temperature Cycling Test - 1000 Cycles
-40°C to +150°C
5 Minute transition time
30 Minute dwell at each extreme
Basically any cycle that you wish to perform - we can program the thermal shock chamber. Our thermal shock chamber is just one of the many chambers that can be used for in house testing.
