Accelerated aging test services offered at Micom Laboratories to a wide range of industries. Essentially, most of what we do answers one of the three following questions:
- What happened to my product/material/assembly?
- What will happen to my product/material/assembly?
- How strong is my product/material/assembly?
Accelerated aging can be used to answer the first two questions. This can be done in various ways depending on the material/product being tested, what is the intended use and what are the ambient conditions while the material/product is in use. Below are the various Accelerated Aging services Micom offers:
- Salt Spray Testing
- Heat Aging testing
- Climatic Chamber Testing
- Thermal Shock Testing
- UV Testing
- Accelerated Weathering
When doing this type of testing it is important to have a good understanding of the product characteristics, the normal use conditions, what constitutes a foreseeable abuse and what is the product’s life expectancy. In all cases, our customers want to have their answers yesterday. However, to have a good test plan one has to be careful not to expose the product to be tested to conditions that are such that abnormal aging processes start occurring.
Nonetheless there are some basic rules to be followed in all aging test procedures. With the exception of freeze-thaw cycles that assesses the impacts of phase changes, all aging processes increase as a function of the ambient temperature. This acceleration process is governed by Arrhenius’s law:
- k (rate of change) = A exp (-E/RT)
- where E = activation energy
- A = pre-exponential factor
- T = absolute temperature
- R = gas constant
In layman’s terms, any chemical reaction will double its rate with each 10 °C increase. This is why corrosion and UV aging, for example, are both done at temperatures above room temperature. Conversely excessive temperature exposure is not recommended. Indeed, beyond a certain point the molecules of a given material can be supplied with sufficiently high levels of activation energy that will allow them to create some chemical reactions that would not naturally occur even over long periods of time or extremely adverse conditions. Furthermore, in many accelerated aging processes there is an asymptotic behavior for organic molecules i.e.: beyond a certain temperature there is no significant gain; only risk.
Figure #1a: Arrhenius’s law – accelerated aging curves
Arrhenius’s law is general in nature and it assumes the general case where the aging rate doubles every 10oC increase. This ideal case would correspond to curve Q10=2 above. Should this be the case and should you wish to age your products at a temperature of 45 oC, you would need a 10 weeks aging process to simulate one year of real life aging. The accelerated aging factor is not always “2”. If the aging factor is known then the simulation can be adjusted accordingly. For example, should it turn out that the material being tested has an accelerated aging factor of 3 (q10=3 above); for the same aging temperature of 45 oC, the number of normal use weeks of aging would be 4 instead of 10.
Should you need help, our experts will be happy to recommend proper test conditions addressing your specific concerns and needs; call us @ 1-888-996-4266 or contact us today.
Complementary Material testing
In many cases, once the aging process has been completed, physical/mechanical measurements need to be made on the samples to assess if whether or not product properties were modified; Micom offers a whole host of mechanical, physical and physic-chemical tests to quantify the changes in the product/material properties.