Methods for monitoring environmental barrier coatings

A method of monitoring at least one of a temperature and erosion of an environmental barrier coating (EBC) of a hot gas component, said method comprising:

• directing an excitation beam having an excitation wavelength at the EBC deposited on an outer surface of the hot gas component, the EBC including at least a bond coat layer and an outer layer, the hot gas component being fabricated from a ceramic matrix composite (CMC);
• measuring a first fluorescent radiation emitted by the bond coat layer and a second fluorescent radiation emitted by the outer layer of the EBC, wherein the first fluorescent radiation includes a first wavelength and a first intensity, and the second fluorescent radiation
• includes a second wavelength and a second intensity, the second wavelength different from the first wavelength;
• and
• determining at least one of a surface temperature and an erosion amount of the EBC based on at least one of the wavelength and intensity of the measured first and second fluorescent radiations.