Thanks Bob. Finally someone understands and is using my theory.
Ed
On Aug 23, 2013, at 8:05 AM, Bob Higgins wrote:
Recently, Peter published in his blog his reasons for hoping that
the NAE aren’t cracks. After considering it, I believe he misses the
uniqueness, durability, and beauty of the cracks that are being
considered.
To the uniqueness point… Consider that a crack is different than
just two surfaces in close proximity. A crack is like a horn with a
throat of minimum gap: the lattice spacing. Imagine the throat at
x=0 with the crack surface spacing widening as x increases. The
crack provides a unique environment in its smallest regions. Near
x=0, the environment for a hydron asymptotically approaches that of
the lattice. In this region, electron orbitals extend across or at
least into the crack. Perhaps in this near-lattice spacing there is
only room for an H+ ion (the case for Ni, but for Pd there is room
at the lattice spacing for a neutral monatomic hydron). As x
increases, the crack surface spacing (the gap) increases allowing
room for neutral monatomic hydrons. At greater x, the crack spacing
would support neutral H2 molecules, and beyond this, the crack is
probably uninteresting. This unique gradient of hydron boundary
conditions always exists in the crack near it throat (near x=0),
even if the crack were to begin zipping itself open.
To the durability point… In my past I had occasion to work with
MEMS structures. When I first saw MEMS cantilever beams being used
for switches and other functions, my first thought was, “Those are
going to break!” What I learned was that a structure’s strength is
inversely proportional to its size. So a building scaled twice as
large will be half as strong. This is why you can drop an ant from
as high as you wish and he will hit the ground running. Compare a 3
meter diving board (cantilever) to a 3 micron cantilever – the 3
micron cantilever will be a million times more robust. The cracks
being considered for NAE are nanoscale cracks, but our natural
experience is with cracks having dimensions of ~1cm. A 10nm crack,
will be a million times more mechanically robust than a 1cm crack.
At the nanoscale, the two split apart surfaces will be very stiff
and behind the throat of the crack (x<0) there will be compression
forces trying to restore the crack to its closed position. The
surfaces may also experience a Casimir closing force. A nanoscale
crack will have strong forces trying to heal itself.
If nanocracks can heal, then how would the nanocrack form in the
first place and what could keep the surfaces apart? I believe a
wedge of atom(s) or molecule(s) is needed in the gap to keep the
crack open, and perhaps to form it in the first place. That is why
I am using nanoparticles that will alloy with Ni and then I am
oxidizing the structure. I use iron oxide nanoparticles. I put
down the oxide nanoparticles disposed all across the Ni micro-powder
surface, reduce (or partly reduce) the surface so the iron
nanoparticles can alloy with the Ni, and then go back and strongly
oxidize the metals. When the iron oxidizes, it grows in volume and
I hypothesize that it will wedge open a nanocrack. If the iron is
then partly reduced it becomes an H2 splitting catalyst, right at
the site of the crack.
What a beautiful structure I imagine that to be – a nanocrack with a
sweep of hydron boundary conditions with an H2 splitting catalyst at
its mouth.
Bob
