Wetting of some metallic surfaces can be inhibited by means of ion implantation of the surface prior to its use, thereby promoting dropwise condensation. The degree of wetting inhibition and, in turn, the efficacy of the implantation process vary from metal to metal. Consider a vertical metal plate that is exposed to saturated steam at atmospheric pressure. The plate is t = 1 mm thick, and its vertical and horizontal dimensions are L = 250 mm and b = 100 mm, respectively. The temperature of the plate surface that is exposed to the steam is found to be T_s = 90°C when the opposite surface of the metal plate is held at a cold temperature, T_c.
(a) Determine T_c for 2024-T6 aluminum. Assume the ion-implantation process does not promote dropwise condensation for this metal.
(b) Determine T_c for AISI 302 stainless steel, assuming the ion-implantation process is effective in promoting dropwise condensation.