WEIGHT LOSS OF PLATED METALS HEATED IN VACUUM
ROCK ISLAND ARSENAL IL
Pagination or Media Count:
A series of experiments were conducted with 0.5 mil plated coatings on steel exposed to heat in vacuum. The plated coatings were cadmium, zinc, lead, nickel, and tin. Test conditions were exposure to vacuum at 0.000015 torr and temperatures from 200 deg F to 675 deg F. Periodic weight change measurements were made in room atmosphere using an analytical balance. Only slight variations of weight were observed with tests of lead, nickel and tin. Cadmium volatilized at rates of 3.0 to 7.6 mgmsq cm day for temperatures at 400 deg F. Zinc coatings behaved in an unusual manner. An initial rate of weight loss occurred at 435 deg F only to decrease to zero at 450 deg F with apparent constant weight. With increased temperature a rate of loss was resumed and rates of 4.5 to 6.5 mgmsq cmday occurred at 550 deg F to a total loss of 90 coating weight.
- Coatings, Colorants and Finishes