On the Characteristics of Ion Implanted Metallic Surfaces Inducing Dropwise Condensation of Steam

Abstract

The present work provides new information on the characteristics of ion implanted metallic surfaces responsible for the adjustment of stable dropwise condensation (DWC) of steam. The results are based on condensation experiments and surface analyses via contact angle (CA) and surface free energy (SFE) measurements as well as scanning electron microscopy (SEM). For studying possible influences of the base material and the implanted ion species, commercially pure titanium grade 1, aluminum alloy Al 6951, and stainless steel AISI 321 were treated with N þ , C þ , O þ , or Ar þ using ion beam implantation technology. The studies suggest that chemically inhomogeneous surfaces are instrumental in inducing DWC. As this inhomogeneity is apparently caused by particulate precipitates bonded to the metal surface, the resulting nanoscale surface roughness may also influence the condensation form. On such surfaces nucleation mechanisms seem to be capable of maintaining DWC even when CA and SFE measurements indicate increased wettability. The precipitates are probably formed due to the supersaturation of ion implanted metal surfaces with doping elements. For high-alloyed materials like AISI 321 or Hastelloy C-276, oxidation stimulated by the condensation process obviously tends to produce similar surfaces suitable for DWC.

The Impact of the Electric Field on Surface Condensation of Water Vapor: Insight from Molecular Dynamics Simulation

“…Vapor condensation is a widespread natural phenomenon which includes the formation of mist and rain [1], the production of droplets on a cooling surface [2], and so on. It is also an important process in industries such as thermal management [3], water desalination [4], and refrigeration [5].…”

Studies on the Origin of Dropwise Condensation of Steam on Ion Implanted Metallic Surfaces

“…Ionenstrahlimplantation [5] mit Stickstoff-, Kohlenstoff-, Sauerstoff-oder Argonionen bei unterschiedlichen Ionendosen und Implantationsenergien. Für Details zur Probenpräparation sei auf frühere Veröffentlichungen [6 -8] [7,8]. Die Analyse der mikroskopischen Oberflächenrauigkeiten erfolgte mit Hilfe der Rasterkraftmikroskopie (AFM-System Veeco Dimension 3100, Digital Instruments) sowie der Rasterelektronenmikroskopie (REM-System JSM-6400, JEOL).…”

Review of Micro–Nanoscale Surface Coatings Application for Sustaining Dropwise Condensation

“…where e is the surface energy, E represents modulus of elasticity, and a is a constant. However, Rausch et al [105] stated that it is not still very clear as to what characteristics of the ion-implanted surfaces made them feasible for DWC. In another study of ion implantation of N + ions on a titanium surface, the ability to achieve and sustain increased DWC was pointed out [106].…”

“…Their results suggested that particulate precipitates caused inhomogeneity on the surface. This nanoscale roughness and surface chemical inhomogeneity helps in nucleating DWC and sustaining DWC even at increased wettability [105,107]. It was supposed that these precipitates were formed by supersaturation of the resultant ion-implanted surface with doping elements.…”