System and method of assessing a coating microstructure

A system comprising:

• an electromagnetic radiation emitter;
• an electromagnetic radiation detector;
• a polarizer;
• and
• a controller in communication with the electromagnetic radiation emitter and the electromagnetic radiation detector, the controller configured to:
• emit an electromagnetic signal through the polarizer onto a coating of a component, the electromagnetic signal having a frequency of at least 0.1 gigahertz (GHz);
• receive a reflected electromagnetic signal from the coating;
• determine a waveform of the reflected electromagnetic signal, the waveform defining a plurality of peaks including a first peak and a second peak subsequent in time to the first peak, each of the plurality of peaks defined as a point where an amplitude of the waveform is greater than respective amplitudes of immediately adjacent points of the waveform and the amplitude is above an amplitude threshold;
• and
• determine a grain density of a microstructure of the coating based on the second peak of the waveform.