Good stuff.
Cerium Oxide is not per se finer than chromium oxide.
Like Cr2O3, Ce02 is a crystal that is available in any size.
You will have to watch out (just like with chromium oxide) if it is fine enough for our purpose.
It is easily available from nanoscale to 300 mesh.
I will tell you a little something about CeO2.
Cerium is a so called rare earth element and chemically spoken it belongs to the lanthanides.
You porbably heard of these in the news.
Ce is the most common element of rare earth ores and has an abundancy of about 60ppm in the upper earth crust.
It is a by-product readily available.
Cerium in its oxide form is often times used as a cheap but highly effective polishing compound,
rivaling and beating diamond containing polishing agents.
It is used as a catalyst in petrolium cracking and in UV-absorbing glasses like the windshield of your car, as well.
What makes cerium oxide so special it can rival almost any industrial polishing compound?
Therefore several polishing theories have to be explained.
Yes, there are several and none of them is considered "proven".
The first and most logic one is the "mechanic" theory.
It describes peaks on every surface that are removed during a fine polishing action leaving a less rough surface. This theory explains these actions with tiny surface "cracks".
The second theory is the "flowing" theory. It describes a plastic flow due to high forces. Surfaces are plastic at micro-level.
this can be illustrated easily: try to bend a 3mm bar of aluminium.
You can´t. Now try to deform a 13µm thick aluminium foil. Now you can!
The third theory is a solely chemically one.
It describes some kind of pickling action.
The surface to be polished is chemically attacked by the abrasive (wich will btw. do actions according to theory 1 and/or 2 as well).
This changes the properties of the surface, as it now consists of a new material. It might change it´s resistance to wear and abrasion, or might be soluable in water.
CeO2 is known to provide such chemical processes.
BUT, and that´s the downside, this works for glass only!
CeO2 is suspected to be able to react with silicon atoms in glass,
creating a surface that is either soluable in water or has a soft consistancy like gel.
Al2O3 and diamond are not known to have such effects.
Combined with usual abrasive action much smoother results can be achieved.
I highly doubt this would work for steel.
And I highly doubt we would have a benefit from it,
as smooth surface and low roughness are incomparable with smooth edges and low roughness of edge!
For metal works, CeO2 is just another polishing agent.
Unfortunately it does not provide as good results in metal polishing as it does in glass polishing,
where it is highly regarded.
BTW. Cerium Oxide does not care if your blade is hardened at 40°, 50° or 65° HRC.
It is also not true that older blades are softer.
It exceeds the hardenes of steel anyways!
(can you say overkill?)
