New study has revealed a method to spot the defects in thermal barrier coatings to protect jet engine turbines from high heat. The new derived optical analysis technique used to predict the thermal coatings life span present on an airplane. Also leads to new thermal barrier coatings also to check engines more efficient and decreasing the cost and pollution of air travel.
The researchers showed changes in refractive index, to measure speed of light travelling through a material. Observing with metal coated piece of ceramic thermal barrier coating drawing it in a controlled manner. The research team is participating with Rolls-Royce, a leading manufacturer of jet engines.
Implementing GHz illumination
The thermal barrier coating life span on turbine blades can range from 1,000 hours up to 10,000 hours at heavy thrust. However, the researchers tested their technique with the same ceramic coatings on pieces of metal sprayed used on Rolls Royce turbine blades. Gigahertz illustration is key to the new technique because wavelengths can travel through opaque materials.
Further, They ceramic pieces placed into a tensile machine that applies strain by pulling the metal. Researchers implement GHz illumination (280-380 GHz) during the process. These generated waves traveled through the ceramic coating and bounced off the metal beneath.
The reflected light measured using a polariscope to determine refractive index of the ceramic changes by the applied strain. Moreover, researchers only obtain the current optical setup with point-based measurements. This technique helps in imaging to analyze an entire blade.
In addition, the researchers are organizing the experiment using higher frequency illumination in the terahertz (THz) range. This improve the technique’s spatial resolution. In collaboration with Cranfield University, UK. The technique used by them is strain measurements of ceramic-coated metal samples that undergo accelerated aging.