Final Report - Strategic Environmental Research and Development ...

2. Technology Description
2.1. History of the development of ESD
ESD is known by a number of names, including electrospark alloying (ESA), spark
hardening, spark toughening, pulse fusion surfacing (PFS), and pulse fusion alloying
(PFA). The spark deposition phenomenon was first reported by H.S. Rawdon at the U.S.
Bureau of Standards in 1924 [3]. Rawdon’s research included sparking pure iron with a
similar electrode, resulting in a significant hardening of the substrate surface. The
sparking led to the formation of martensite (an interesting outcome for a non-carbon
containing iron material). The martensite formation resulted from the rapid quenching of
the tiny volumes of iron that underwent a very rapid melt/freeze cycle – a form of rapid
solidification. Rawdon’s observation was repeated and reported by N.C. Welsh in 1957
[4]. Welsh went on to show that very hard surfaces could be deposited on steel by
sparking it with electrodes of tungsten carbide and tungsten/titanium carbide. He also
hardened the surfaces of copper, brasses, aluminum and titanium.
Starting in the mid 1940’s, and continuing on to the present day, many studies of the
spark deposition process have been reported by researchers in the former Soviet Union
(now Russia and Ukraine). The primary focus of that work appears to be for increasing
life of tools and wear-prone machine components.
A moderate amount of work on spark deposition has been reported in the U.S. over the
past three decades [5-9]. Much of that work was done at, or in collaboration with, the
Battelle Pacific Northwest National Laboratories (PNNL), formerly Westinghouse
Hanford Company, in Richland, Washington, and Washington State University (WSU) in
Pullman, Washington. Their research has led to the development of high performance
coatings on nuclear reactor components, wear and corrosion resistant coatings for coal
gasification equipment, and important improvements in spark deposition equipment.
Since 1988, additional improvements in the spark deposition equipment have been made
by Advanced Surfaces And Processes, Inc. (ASAP) in Cornelius, Oregon. The improved
equipment, controlled by a microprocessor and advanced electronic circuitry, has been
utilized by a number of research laboratories, universities, government and military
agencies, and private companies.
Research and development on ESD is increasing as the awareness of the capabilities of
the process expands, with important work being done and reported by such R&D groups
as Edison Welding Institute (EWI), The Welding Institute (TWI in UK), Battelle Pacific
NW National Laboratories (PNNL), and the National Institute of Science of Ukraine.
Universities presently pursuing ESD development projects include: The University of
Waterloo, Ontario, Canada; University of Manitoba, Manitoba Canada; Queens
University, Ontario, Canada; Portland State University, Portland, Oregon, and the Oregon
Health and Science University, Portland, Oregon.
A number of private U.S. corporations are presently contributing to the expanding
knowledge base of ESD Technology as well. Among these are Rolls Royce Corporation,
General Electric Aircraft Engines, General Electric Power Systems, Pratt and Whitney,
Advanced Surfaces And Processes, Inc., ATK Thiokol, Moog, Hamilton Sundstrand, The
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