Almost all cast, forged, extruded or wrought
aluminum alloys can be treated. Alloys that
contain less than 5% copper and 7% silicon and
do not contain lead are most suitable for the
application of an HCR coating. The degree of
hardness, penetration and color varies with each
alloy, with the processing temperature, and with
the coating thickness.
NASA tests¹ of Shuttle parts indicate that
parts coated to a thickness of 51 microns (2.0
mils) "should provide superior corrosion
protection for a prolonged period of time."
MAGNAPLATE HCR-F is compliant for use in
"food contact involving repeated use, such
as food processing equipment." ²No other
surface enhancement coating can give aluminum
parts 10,000 hours of salt spray corrosion
resistance in food contact applications.
General Magnaplate HCR's coating thickness is
consistently uniform and ranges from
0.001-0.0025" per side. Precise control of
coating thickness (+-10%) permits use on
close-tolerance parts such as prebalanced
impellers and threaded members. By undersizing
the outside diameter by two times and pitch
diameter by four times (for 60 degree thread
forms) of the desired coating thickness, the
original thread size can be maintained after
coating. for machining allowances, note that
overall final thickness of the coating is
influenced by two factors; A Penetration B.
Growth.
The finish of the surface after MAGNAPLATE
HCR application will be equal to or slightly
rougher than the original surface. While not
recommended, slight burnishing, lapping, or
honing can be performed on a coated part, if
necessary. However, removal of the surface
material should be no more than 0.0002".
For machining allowances, note that overall
final thickness of the coating is influenced by
two factors: A. Penetration B. Surface Growth
Enhanced aluminum exhibits rapid heat and
cold transfer. By converting an original single
flat aluminum crystal into millions of surface
facets, MAGNAPLATE HCR permits heat distribution
within the encapsulated outer surface that
surpasses that of untreated aluminum. The
proprietary polymers used in the impregnation
process have a heat conductivity of 1.7 ± .03
Btu/hr/sq. ft/deg. F/in and a heat capacity of
0.25 Btu/lb/deg. F.
¹ NASA Technical Memorandum by M.D. Danford,
Marshall Space Flight Center, April 1991
² FDA letter to General Magnaplate, May 22,
1987 |