Hello everyone , does anyone have any Idea for making longtitudinal porouse Alumina ?
it would be something like the picture below but It would be made out of Alumina
[Edited on 24-12-2014 by wish i had a kraken!!!]
the picture u are observing is a cross sectional view of longtitudinal porous copper
[Edited on 24-12-2014 by wish i had a kraken!!!]wish i had a kraken!!! - 25-12-2014 at 10:11
The picture U see above is a cross sectional view of a lotus type porous copper , I made them this way:
1.I had wires of Al coated with copper
2.I packed the coated wires in a copper tube
3.I extruded the billet
4.I put the produced sample in NAOH solution ,for a night and The next day the Al was gone!
[Edited on 25-12-2014 by wish i had a kraken!!!]
Bert - 25-12-2014 at 17:07
Nice work- How long/what Dia. segments of finished honeycomb have you achieved?
There are other techniques for producing alumina honeycomb substrates for catalytic reactions- see here:
Tidbit
"Catalytic converters are commonly made from ceramics containing a large proportion of synthetic cordierite. The manufacturing process deliberately
aligns the cordierite crystals to make use of the very low thermal expansion seen for one axis. This prevents thermal shock cracking from taking place
when the catalytic converter is used." http://en.wikipedia.org/wiki/Cordieritewish i had a kraken!!! - 26-12-2014 at 07:49
"Catalyst Synthesis
Aluminum nitrate {Al(NO3)3-9H2O, 99.5%}(Merck), Ammonia {NH4OH, 32%} (Merck) and deionized water were used as starting chemicals. A transparent
gel-like precursor containing Al cations is precipitated at pH ~7.5–8.5 when ammonia (%3.2) and Al nitrate salt solutions (0.26 M) are mixed
together in 400 ml deionized water. The solution was mixing under ultrasonic vibration and maintained at a temperature 70 ºC for 2 h. The following
chemical reactions occurred during preparation:
Al(NO)3 + 3NH4OH = Al(OH)3 (s) + 3 NH4NO3 (2)
Al(OH)3 = AlOOH (s) + H2O (3)
2 AlOOH = Al2O3 + H2O (4)
The precipitate obtained by reaction (2) was aged at a temperature ~70 ºC helped to homogenize the gel due. The ageing step is essential to convert
Al (OH)3 to crystalline boehmite precursor by reaction (3). The precipitate is further processed by washing in deionized water. Then was added 300 ml
ethanol to the filtered Al(OH)3 under ultrasonic vibration for 1 h then dried in oven at ~70 ºC for 18 h. "
Unfortunately, there is a downside to working with nano alumina, per a paper citing that nanoparticles kill and maim blood vessel cells found in the
human brain, Oct 21, 2008 by Chen, L, RA Yokel, B Hennig and M Toborek, "Manufactured aluminum oxide nanoparticles decrease expression of tight
junction proteins in brain vasculature" in Journal of Neuroimmune Pharmacology doi:10.1007/s11481-008-9131-5y.
Apparently a study using cells and rats indicated that nanoparticles of aluminum oxide can kill and adversely change the special cells that line the
blood vessels in the human brain.
[Edited on 30-12-2014 by AJKOER]wish i had a kraken!!! - 30-12-2014 at 10:39
AJOKER , thanks for your reply , but Alumina coated with Pt are used in some special fixed bed Cracking reactors , I think if we could make a thing
like the picture may be we could enhance the yield of cracking reactions., So , I think maybe Nano particles are not good for this purpose.
