It's more the cast aluminum alloys that are a worry with ethanol, thus
the concern in cast engine blocks and similar mass-produced car parts.
Propellant tanks are typically wrought alloys of significantly
different composition. Aluminum corrosion generally is sensitive to
temperature. Isopropanol isn't corrosive at room temperature, but is
when you get it up near boiling.
Anodization or nickel plating is straightforward and prevents corrosion.
On Tue, Apr 26, 2016 at 10:45 AM, Henry Spencer <hspencer@xxxxxxxxxxxxx> wrote:
On Mon, 25 Apr 2016, David Weinshenker wrote:
(That said, a lot of rockets have used aluminum tanks for ethanol,
without difficulties that I know of.)
Is ethanol even particularly corrosive to aluminum in the first place?
"Particularly", perhaps not, but slightly, yes. Enough to be a concern on
prolonged exposure, anyway -- I believe it's an issue in substitution of
bioethanol for gasoline as a vehicle fuel. I'd expect that much depends on
details like the exact alloy and the water content of (and other impurities
in) the ethanol.
Henry
