Determination of the deliquesce point in double salts and in in-situ multicomponent salts with DVS equipment

Accelerated salt induced deterioration occurs by frequently changes across the deliquescence point. Therefore does the actual deliquescence point of the present salts have a major impact on preventive conservation being able to ensure a relative humidity not causing salt phase transition and to in-situ desalination as dissolution of the salts is the essential criterion to enable transport of salt (ions) in the construction.
In the present work deliquescence points were measured with dynamic vapor sorption (DVS) equipment in salt mixtures and the results are shown to be in agreement with values from the literature. Also in-situ-multi salt samples were measured including the difference between the second critical relative humidity and the efflorescence relative humidity being a measure for the critical supersaturation required for crystallization at the specific experimental conditions. The DVS equipment seems to be able to make accurate determinations of the deliquescence points in complex salt systems and could be an expressive determination in in-situ investigations.