Although parylene is known as a strong, reliable coating capable of protecting substrate materials even in extreme environments like outer space, it isn't infallible. Today, we'll cover the expected parylene lifespan, which factors can extend or reduce this lifespan, and why proper application is key.
Parylene Lifespan
Because parylene is often leveraged in critical applications, such as medical devices and circuit boards, it's important to understand how long this coating lasts. Here are a few key details to consider:
Parylene types
Parylene lifespan depends heavily on the type of parylene in question. For example, Parylene N and Parylene C have different lifespans under the same conditions. At 25°C in the absence of light, the lifespans are as follows:
- Parylene N: 2,200 years.
- Parylene C: 130,000 years.
It's important to consider that different parylene types are designed for different conditions. Using the wrong type, therefore, could lead to impacted lifespan or reduced reliability.
Temperature
Note that the above parylene lifespan measurements are only accurate at room temperature. Realistically, parylene is often utilized in more extreme environments--and higher temperatures reduce lifespan. At 200°C, the numbers drop significantly:
- Parylene N: 0.06 hours.
- Parylene C: 0.7 hours.
UV exposure
UV exposure is yet another element that can impact parylene lifespan. At 2500 lux, the measurements are as follows:
- Parylene N: 2,784 hours.
- Parylene C: 20,538 hours.
Other considerations
Keep in mind that parylene is utilized in a variety of conditions--and the more extreme these variables, the more impacted parylene lifespan will be. This is exceptionally true when two or more conditions are present simultaneously--for example, UV exposure and high temperatures.
Other considerations include:
- Oxygen exposure.
- Chemical presence.
- Humidity.
- Moisture.
- Mechanical stress.
- The application process.
The Importance of Application for Parylene Lifespan
Improper application can lead to greatly impacted parylene lifespan. The results can range from reduced durability over time to early coating failure, which can prove critical in certain applications--especially those in which the coating can't easily be replaced (like aerospace or medical devices).
Application issues
Application issues can take a variety of forms depending on the project, equipment, and expertise of those involved. For example, an unclean substrate surface can lead to issues that eventually impact parylene lifespan. Other issues include:
- Improper coating thickness.
- Varying temperatures during the application process.
- Uneven coating distribution.
- Incompatible materials.
- Shifting pressure.
- Surface contamination.
Improper application results
If mistakes are made during the application process, parylene can be impacted in specific ways, including:
- Pinhole or pore formation.
- Blistering.
- Thinning.
- Cracking.
Conclusion
To maximize parylene lifespan and complete a problem-free project, it's necessary to understand the conditions in which your coating will be expected to perform, as well as the conditions that may impact the application process. You must also choose the best parylene type for your specific needs. Perhaps most importantly, you must identify and reduce errors during application to create a strong, reliable bond between parylene and the substrate surface.
If you're pursuing a parylene project, you'll likely want support throughout the process. Contact us today for help maximizing parylene lifespan and simplifying your projects.
