PHOTOTHERMAL STUDIES OF COPPER PATINA FORMED IN THE ATMOSPHERE

A new photothermal approach in the studies of patinated copper layers is proposed. A non-contact and non-destructive photothermal beam defle ction (PBD) method has been used for the characterisation of the therm al properties of patinated copper samples from the roof of the Stockho lm City Hall. Measurements of thermal diffusivity and layer thickness performed on both the outdoor and indoor sides of patinated samples sh ow a significant difference in their thermal properties. Photothermal images obtained for both sides of patinated samples have been used for the analysis of patina layer surface morphology and the microstructur e of inclusions.