tfagan wrote:
Thanks for the reply could you recommend a ph limit, I was thinking
around
the 10.4 range. The reason I ask is I keep telling them to look for
another
cleaner and keep getting this is the only approved cleaner. I try to
tell
them that alkaline cleaners can harm the AL and especially at increased
temperatures that are required for the cleaner.
The only way to know for real is to test it for real. The higher the
temp and the higher the pH the more aggressive the corrosion.
However, a high pH cleaner may have a better corrosion inhibition
package than a lower pH but still alkaline cleaner. Remember to put a
deep scratch into your test blank immediately before immersion. You
want to know what happens in the dirty real world of modest
mentalities on the production floor.
You must test your actual basket. Alumnum foil is a different alloy
with different mechanical stress and heat treat histories.
You might google and patent search anti-corrosion packages for
automobile antifreeze that goes into aluminum engine block and
radiator engines. It would be a shame to write off a 50 gallon vat of
premium cleaner for want of a dollar's worth of additives.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
"Uncle Al" <UncleAl0@hate.spam.net> wrote in message
news:3F75B1AC.333928F5@hate.spam.net...
tfagan wrote:
Will alkaline cause AL to corrode. If so why do they keep selling
part
washers and recommend alkaline cleaners, I know it's primarily
because
of
the soils to be removed be if there is a chance that it will cause
corrosion
and most a/c part are made of it why take the chance. What would be
a
safe
ph level, since most are mixed with water and we know water will
evaporate
in these heated part cleaners that do not recommend doing a ph check
prior
to putting parts in them. Is there a list of what type of cleaner
should be
used with what metal because I don't think the label safe for all
metals
really is correct, there to many metals that react differently to
different
chemicals for that to apply to all metals
Aluminum is amphoteric. It dissolves in either acid or base, e.g.,
2Al + 2NaOH + 6H2O --> 2NaAl(OH)4 + 3H2
Anything that breaches the protective oxide coating will attack
aluminum like a buzzsaw.
Alkaline cleaners are good at removing animal fats and oils via
saponification. They are also good at corroding and then dissolving
aluminum. Alkaline pitting is especially nasty. Attack upon the
metal depends on the alloy, anodization, and anti-corrosion additives
in the cleaner. I would not use aluminum in an alkaline bath unless I
did an accelerated ageing test. Remember to add a deep scratch to
part of the test specimen immediately before immersion
If you are hanging aluminum baskets from steel hooks, worry about
galvanic corrosion too. The expensive aluminum will protect the cheap
steel.
--
Uncle Al
