Accession Number:

ADA230855

Title:

Surface Dynamics of Unipolar Arcing

Descriptive Note:

Master's thesis

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

• Downs, Richard K.

Report Date:

1989-12-01

Pagination or Media Count:

100.0

Abstract:

A 4.55 microsecond, 15 Joule pulsed CO2 laser was used to illuminate a copper target. Bulk plasma was found to be emitted normally to the target surface independent of the laser angle of incidence over the range of 45 deg 15 deg. Material ejected from a copper target was allowed to deposit onto polished type 304 stainless steel surfaces. The ejected material deposited in concentric rings in many places. The mechanism for this is unknown. Polished type 304 stainless steel surfaces were coated with one to ten micron copper films and shot with the laser. Damage to the films indicate that the damage mechanism may simply be joule heating from the arc current. This lead to a procedure for calculating that arc current. the arc lifetime is necessary but still unknown. no correlation was found between unipolar arc pit diameter and depth.

Descriptors:

• *ARC WELDING
• DAMAGE
• DYNAMICS
• PLASMAS(PHYSICS)
• FILMS
• TARGETS
• SURFACES
• COPPER
• HEATING
• ELECTRIC CURRENT
• RINGS
• ELECTRIC ARCS
• ANGLES
• LASERS

Subject Categories:

• Lasers and Masers
• Metallurgy and Metallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE