Monitoring of corrosive environment aggressiveness and development of a sensor for monitoring of the water film in exposure chamber

Exposure of copper in corrosive environment is possible way, how to obtain artificial patina. Various solutions based on chloride, ammonia or polysulfide are commonly use in this purpose. Furthermore, it appears that the patina is also formed in an environment with an increased concentration of SO₂ in the atmosphere. This procedure was tested in a small (30 l) exposure chamber, where the aggressiveness of the environment was monitored and where the effect of alternating the condensation and drying phases was shown to be positive. Based on this experiment, a 2 m³ pilot chamber was designed for which a water film sensor was developed and tested to ensure drying of the object surface. Monitoring of the aggressiveness of the environment showed that the pH and SO₂ concentrations in the atmosphere are stable after approximately 5 hours and the ideal input SO₂ concentration is 17.7 g m^-3 at which the pH stabilizes at 2.7-3. By recording the voltage variation on the sensor, it was possible to monitor the formation and drying of the water film during the cycling of the condensation and drying phases.