| In experiments
conducted from 1990 onward we regularly observe destruction of
palladium metal foils when exposed to intense transient
cavitation as a result of ultrasonic stimulation. Upon
examination the metal foils are found to have large apparently
melted holes. Using scanning electron microscopy with the
assistance of Professor John Dash, Portland State University and
electron microscopists at Charles Evans and Associates we have
examined these samples and found extraordinary features which
are not characteristic of any reported form of cavitation
damage. The features have the appearance of "volcano like"
ejecta fans and vents. We propose micro nuclear explosions some
microns deep in the foil have resulted in explosive cavities
many microns in diameter filled with superheated metal. Where
these super hot regions have been near enough to the surface of
the foil they have erupted through the surface spewing molten
and gaseous metal. Additional evidence of the micro nuclear
reactions is found in large amounts of helium which is observed
in the palladium metal following the experiments (described in a
separate paper). The following photos and scanning electron
micrographs illustrate features at successively higher
magnification. |
|
Photos and SEM Micrographs of Micro Nuclear
Melting Effects on Palladium Foil |
Pd target foil 5cm x 5cm x 0.1mm
Circular punches were taken as reference
samples before and after the experiment and
subjected to TEMS and density analysis
|
| This
characteristic destruction of the foil and melting is
composed not of one but of countless thermal ejecta events.
Over a time frame of minutes to hours, depending on
controlled experimental parameters the foil is destroyed and
the reactions halt. Various metals reveal different
characteristic damage. Under
scanning electron microscopy the small volcano like craters
which remain following an eruption of molten or gaseous
metal are readily found. The ejecta event starts as the
micro-nuclear event(s) produces an explosive cavity within
the lattice. The heat from the event producing the cavity
must occur very rapidly as the metal lattice can rapidly
transfers heat to surrounding lattice atoms and into the
circulating water in which the reaction takes place. The hot
atoms nearest the explosion will either transport its heat
to the surrounding lattice until the lattice atoms
re-solidify or the hot metal will break the surface of the
lattice and spring out as gaseous or molten ejecta. These
events are captured in the following SEM photos. Such ejecta
are readily identified by their cone and fan shaped craters
radiating out from a cylindrical vent. The similarity with
volcanic events on geological landscapes is remarkable.
Some ejecta craters or fans are often littered with tiny ~1
micron fused spheres of metal which have the appearance of
sputtered metal. For a sense of scale the bubbles which
produce the driving force for the reactions are smaller than
these 1micron spheres. The metal spheres can be observed to
have good contact with the metal as little electron charging
is observed. Other ejecta craters or fans are glassy smooth,
an indication that the metal was ejected at a very high
temperature, either a gas or plasma. |
Magnification 50X showing region near
central melted hole. 
Magnification 100X showing highly altered surface |
 |
Sem image shows at 420x showing volcanic like ejecta
event where
hot gaseous metal has been ejected from
deep within the lattice. |
|
|
Wide shot of another volcano like feature
close up follows  |
SEM at 3200x of a site where molten metal hasbeen
ejected. Metal has
solidified on the bottom of the
ejecta crater as 1 micron sputtered beads.
The
cavitation bubbles which collapse on the metal are much
smaller than these metal spheres. |
| A
thorough search of the literature and discussion with
experts in cavitation revealed no previous reports of
similar damage to metals from common forms of cavitation
(erosional) damage. Consultation with experts in nuclear
materials nuclear fuels has resulted in a report of
previously observed very similar metal damage. This
precise kind of damage to metals is consistent with
damage seen in materials such as Californium which
undergo spontaneous nuclear fission. Indeed such volcano
like eruptions have been characterized as resulting from
large numbers of spontaneous fissions resulting in
"spike damage." |
| One
can calculate the energy involved in such ejecta
events. Using the SEM images an accurate measurement
of the ejecta vent and crater dimensions are readily
estimated. In a simplified treatment we assume the
volcano like ejecta craters are simple circular
cylinders. Using the measured dimensions we
calculate the molar volume of Pd in the cylinder.
From there it is a simple calculation using heat of
fusion and vaporization for Pd to calculate the
energy required for the observed lattice effects. In
these calculations we ignore heat losses which
certainly occur. |
|
In cases where the lattice is melted and ejected
as molten metal ignoring heat loss due
conduction and other means we estimate a number
of hypothetical nuclear reactions at ~24mev per
event occurring simultaneously to produce a
large ejecta event. |
Table of Energy/Reactions for an event
producing melting |
 |
|
Events of approximately 10 microns in
diameter and 10 microns deep as pictured in
the preceding SEM images have required about
400,000 events if one assumes, just for the
sake of a yardstick, a D+D-> 4He reaction
releasing 24 MeV of energy. The D+D
->4He reaction is not being identified here
as a proposed reaction but is one of many
candidate reactions possible. Naturally, the
absence of a 24Mev gamma suggests this
precise reaction as known to hot fusion and
beam science is not likely. |
|
For those cases where the metal leaves
the "volcano" in a gaseous state the
event energy is much higher as shown in
the following chart. |
Table of energy/reactions for an
event
producing vaporous ejecta
Further studies with palladium and a
variety of other metals are underway
to characterize the reactions and
reaction energy available. There is
a large difference between materials
with some producing more vigorous
destruction that with palladium and
others almost none at all.
Correspondence with the author is
encouraged
E-Mail to the author
 |
