Accession Number:

ADA028453

Title:

A Scanning Electron Microscope Study of the Effects of Anode Velocity and Current Density on the Corrosion of Ship Hull Zinc in Synthetic Seawater

Descriptive Note:

Master's thesis

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

Report Date:

1976-06-01

Pagination or Media Count:

172.0

Abstract:

Corrosion can be generally defined as a chemical or electrochemical process by which a metal is attacked in its environment. Coverage of one aspect of the electrochemical nature of corrosion to explain the cathodic protection phenomenon is presented. The structure of corrosion products formed on anodic ship hull zinc due to impressed current in synthetic seawater electrolyte was studied as a function of anode velocity, current density, and current-time product. A model is developed considering hydrodynamic and diffusion boundary layer effects on electrical double layer stability. Conditions leading to the formation of various corrosion product types are defined and their development with time is followed. A model controlled by current density is offered for static conditions at low and moderate current densities leading to either non- passivating network layers or compact passivating layers depending on the conditions. A corrosion cycle is hypothesized for very-high current densityhigh velocity situations.

Subject Categories:

  • Properties of Metals and Alloys
  • Marine Engineering

Distribution Statement:

APPROVED FOR PUBLIC RELEASE