A porous metallic coating is provided. The coating is characterized by a combination of optimized properties that improve coating performance, as measured by heat transfer efficiency. The porous coating has optimal ranges for properties such as porosity, particle size and thickness, and has particular applicability in boiling heat transfer applications as part of an air separations unit. The porous coatings are derived from slurry-based formulations that include a mixture of metallic particles, a binder and a solvent.