Smart coatings for aerospace composite testing

OliKrom and Airbus have collaborated on a color-based, aerospace component inspection technology that indicates the location of the collision and the temperature overheating.

Ph.D., Sophie Senani, a surface structure processing research engineer at the Airbus Research Center, said: "In the past five years, cooperation with Olikrom has been committed to innovation in two areas of external color-sensitive coatings: cum stress, temperature."

The origin of the project's development was initially directed at the detection of composite materials subjected to pressure collisions.

The different parts required by Airbus, the transportation from Europe to the final assembly line, and even the risk of collision and crushing of parts encountered during the assembly process cannot be ruled out. Non-destructive testing by ultrasound can detect any component damage that needs to be repaired, but the process is lengthy and takes about two hours to detect one square meter.

The paint developed this time can be observed by the naked eye at any point beyond the threshold limit of collision damage. The color of the paint changes depending on the pressure change after the impact.

“This is done to facilitate the detection of the area of ​​the collision during the assembly process. Compared to the current structure, the use of ultrasonic inspection will only be limited to detecting critical areas that are susceptible to damage due to time. So this method can Save a lot of production assembly time."

In addition to this initial project, the two parties have collaborated to develop a heat sensitive coating that can be used for local overheated component inspection near hot areas such as the hood.

Similarly, the purpose of this test is to improve safety and quickly identify damage points that have been rarely detected in the past, such as hot air leaks, in order to plan maintenance and protection work to guard against potential damage risks.

“Thermal technology has long existed, but the chemicals developed by OliKrom provide higher accuracy in temperature conversion thresholds and have longer-lasting performance, both of which are critical in the aerospace industry.”

The new coating is designed to produce different effects after two temperature thresholds. The initial color must change at 120 ° C and change again when the temperature reaches 140 ° C.

These two thresholds, while taking into account the marginal mass of composite damage, constitute a first level warning of components near the engine.

“If we can detect areas where the parts are overheated, even in small areas, preventive maintenance can be implemented to further improve aircraft reliability.”

For these two innovations, the related concepts have been confirmed in the actual components. In order to achieve the application of new coatings in the industrial phase, work is currently being carried out according to the specific specifications of the relevant components to accommodate different pressure and/or temperature thresholds.