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Climatic Chamber - Thermal Cycling - Environmental Testing

Materials Technology have recently expanded our environmental testing capability to include a state of the art climatic chamber. With our climatic chamber we are now able to simulate cyclic thermal loads at a range of relative humidities and typical operational temperatures.

The various materials in a component can have different coefficients of expansion, resulting in thermal stresses and premature failure. Constant temperature operation is often not the cause for failure. More commonly it is the stressing induced by temperature cycling which does the damage. Combine that with condensation and the potential for shortened life can be easily anticipated . Well designed and manufactured products can withstand the repeated stress reversals of heating and cooling without failure. Conversely incompatible materials can result in premature failure of otherwise well made components.

Subjecting a material, combination of materials or finished product to thermal cycling provides information on their resistance to thermal fatigue, a degradation and failure mechanism common in a variety of industries. A component that is expected to operate at or is exposed to multiple temperatures will be forced to contract and expand mechanically, having a significant impact on any joints or bonds between heterogenous materials. Other possible side effects of thermal cycling may be changes in solubility or conductivity, as well as fatigue failure.

A product's performance during storage, transportation and normal operating conditions may be assessed using such equipment.
The use of thermal cycling to test for bond strength is largely considered to be superior to other options where possible. Mechanical testing in this case is useful to define failure points, but struggles to extend to predicting long term effects, such as fatigue or transient bond separation caused by materials with different expansion co-efficients. Thermal cycling at differing gradients accurately simulates any transient effects, whilst also reducing potential damage to the non bonded surfaces.

In service, temperature cycling can be caused by the operational environment. It can also be due to internally generated heat from for example automobile electronics systems or aerospace components. Where relevant products can be tested ‘powered up’ to increase thermal shock.

We operate test chambers capable of simulating a wide range of climatic conditions, at a variety of different BSI, ISO and ASTM standards.

Achievable temperatures range from -40 ℃ to 180 ℃, at gradients of 4 ºK/min. Relative humidity can be adjusted from 10 to 98 %. This, combined with the programmable features of our equipment, allows us to develop complex testing cycles involving multiple temperatures with defined dwell and ramp periods. A series of probe ports allow for additional in situ environmental monitoring of alternative parameters if required. This can also allow for components to be tested whilst powered if necessary - occasionally, the internal heat generated by power systems can have a significant effect upon the construction's performance.

Our test space has a volume of nearly 200 litres measuring 750 by 650 by 400mm. Following exposure, physical testing (tensile etc.), colour checking or other analytical processes can be applied to your samples. We can offer short duration testing of samples (<1 day) or very long duration testing at competitive rates.

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