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SALT
SPRAY ARTICLE
As
quality control continues to be our top priority, the need
for destructive testing of plated parts has increased. The
most common test is called a Salt Spray Test. This test measures
the platings corrosion protection potential. This test is
known as accelerated corrosion test. The Salt Spray Test uses
a 5 % salt solution dissolved in water that is sprayed over
the parts in a closed cabinet. The parts are checked daily
and visually inspected. The test is to first measure how well
the chromate (color) protects the Zinc plating deposit. This
is how many hours it takes to wear through the chromate which
causes the Zinc or Cadmium to rust and form its characteristic
white rust. This is reported as hours to white corrosion products
(rust). The next step is to continue the salt spray test until
there is red rust noticeable, which means that the plating
has given way and allowed the part itself to corrode. Iron
corrodes with red corrosion products and is reported as hours
to red corrosion products. The better the chromate the longer
is takes to see white corrosion. Red corrosion is slowed down
by the thickness of the plating deposit.
As you
can see it can be complicated to determine what type of plating
will pass your customers requirements. The best way is to
consult with BPS to determine
what thickness and chromate type would be best. The only way
to know for certain is to test the parts.
Please
contact us if you have any further
questions. |