A study of the breakdown mechanism of AISI 304 stainless steel, type 2024 aluminum and various titanium coatings
Beelby, Michael Howard
Ulrich, Henry George, III
Challenger, Kenneth D.
MetadataShow full item record
An investigation, experimental and theoretical, into the breakdown mechanisms and associated minimum power levels required for the breakdown and unipolar arcing was conducted for AISI 304 stainless steel and Type 2024 aluminum. The experiment was conducted using a neodymium-glass Q-switched laser. A system of filters was used to attenuate the irradiance on target to the point at which no damage was discernible following laser-target interaction. Experimental results show that above a certain critical power density, surface breakdown occurs. The primary mechanism of surface damage at the power density threshold is by unipolar arcing. Titanium coasted stainless steels were exposed to energy density levels on the order of 5 GW/CM(2). The titanium coating significantly reduced or eliminated the number of unipolar arcs observed. A model is proposed for the physical processes involved in the first few nanoseconds before breakdown.
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
Showing items related by title, author, creator and subject.
Unipolar arcing, a basic laser damage mechanism Schwirzke, F. (Monterey, California. Naval Postgraduate School, 1985-05-05); NPS-61-83-008Unipolar arcing has been shown to be the primary plasma-surface interaction process when a laser produced plasma is in contact with a surface. Evidence of unipolar arcing was found on all targets irradiated at atmospheric ...
Energy threshold for laser induced breakdown on a metal surface under high and ultra high vacuum conditions. Gedik, Abdullah (Monterey, California. Naval Postgraduate School, 1991-06);Unipolar arcing is the primary breakdown process when a powerful laser pulse interacts with a target surface. The unipolar arc model assumes that the initial ionization occurs in desorbed gas layers. To check this ...
X-ray pulse considerations and electron flow in high voltage vacuum diodes Callahan, Michael O. (Monterey, California. Naval Postgraduate School, 1993-12);Electrical breakdown in high voltage diodes has been studied since the 1920s, yet it is still not well understood. This study characterizes the electron flow during breakdown in a high voltage vacuum diode. This was ...