Drying of salt solutions leads to the accumulation of salt at any surface where evaporation occurs. When this drying occurs within porous media, the precipitation of salts or efflorescence is generally to be avoided. A one-dimensional model for the drying processes in initially saturated porous materials was presented by Huinink et al. ͓Phys. Fluids 14, 1389 ͑2002͔͒ and analytical results were obtained for short times when the concentration distribution evolves diffusively. Here, we present analytical results for intermediate times when convective and diffusive fluxes balance. Moreover, the approach is extended to symmetrical geometries and is generalized for porous objects with arbitrary shape, which highlights the role of the surface area to volume ratio. Estimates for the Peclet number dependence of the maximum salt concentration at the surface are obtained and the conditions that allows to avoid efflorescence are characterized.

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Weldability, microstructure and tensile properties of CM64 and Tribaloy T-800 (T800) cobalt-based hard-facing materials were studied. Successful CM64 hard-facing could be achieved at ambient temperature using manual gas tungsten arc welding (GTAW-MA). It was shown that T800 welded at ambient temperature was prone to cold cracking due to a combination of low ductility with high welding stresses that limited accommodation of residual stresses by a plastic deformation within the weld beads, which was not the case for CM64 welds. Sound T800 welds of various geometries and sizes were produced on cobalt- and nickel-based superalloys using GTAW-MA when preheating above 900°C was applied prior to welding. T800 welds possessed lower ultimate tensile strengths and elongations from room temperature up to 1093 ºC when compared to CM64 alloy.