Gold Surfaces for Dropwise Condensation

Woodruff, David Winfield

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Description

Title

Gold Surfaces for Dropwise Condensation

Author(s)

Woodruff, David Winfield

Issue Date

1980

Department of Study

Chemical Engineering

Discipline

Chemical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Engineering, Chemical

Language

eng

Abstract

• Gold surfaces were investigated as promoters of dropwise condensation of steam at atmospheric pressure. Seven gold electroplating baths, one electroless immersion gold plating bath, and vacuum gold vapor deposition were used as deposition techniques. Five different surface preparation techniques of a pure gold sample were also tested. Gold deposits ranged in thickness from 100(ANGSTROM) to 20,000(ANGSTROM) with major emphasis from 200(ANGSTROM) to 5000(ANGSTROM). Auger electron spectroscopy and scanning electron microscopy were used to describe the heat transfer surfaces chemically and physically.
• The deposits from the bright pure gold plating baths and the "acid, hard" baths produced deposits which resulted in dropwise condensation. Those deposits from the alloyed baths, the ultra-pure bath, and the vapor deposition gave mixed or filmwise condensation. Two surface preparations on the pure gold sample gave dropwise condensation, one gave mixed condensation, and two gave filmwise condensation. One deposit which was 2000(ANGSTROM) thick gave continuous dropwise condensation for over 1000 hours. The results indicate that gold is "self-promoting", adsorbing trace organics from the surroundings which serve to promote dropwise condensation. It appears that the role of the gold is to provide an oxide-free metallic surface.

Graduation Semester

1980

Type of Resource

text

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