The Boc Group, Inc.

Applied Surface Technologies

Robert Sherman

Jeffrey Davidson

Shigeki Hayashi

Takashi Sakanaka

Richard C Paciej

Yoshiyuki Nakahara

Philip W DePalma

Richard Paciei

Humidity within the workspace of a cryogenic aerosol spray cleaning system is controlled by circulating the workspace atmosphere through a dehumidifier. Advantageously, the need for purging of the workspace atmosphere prior to each cleaning cycle is eliminated. A system and method are thereby provided for cleaning of large workspaces. The system amd method of the invention are especially well-suited, economical, and practical for cleaning operations in which a dry air or inert gas purge of a large volume cleaning chamber would be impractical.

System and method for controlling humidity in a cryogenic aerosol spray cleaning system

The present invention provides a method for surface passivating stainless steel articles against the effects of corrosive materials having activities anywhere from aqueous salt solutions to corrosive gases such as hydrogen chloride and silane. Additionally, after the treatment and exposure of the article to moisture, when the article is subsequently flushed with a dry gaseous fluid, the time that the article takes to exhibit an acceptable moisture outgassing rate is reduced over an untreated article. In accordance with the present invention, the surface to be passivated is flushed with a dry gaseous fluid, chemically non-reactive with the stainless steel and containing essentially no oxygen. During such flushing, the articles is baked and cooled. The baking is accomplished at a predetermined temperature and time (preferably between about 250.0.degree. C. and about 500.0.degree. C. for about 4.0 hours) to effect, within the oxide layer, a reduction in adsorbed moisture and hydroxide content and an increase in chromium content. The article is allowed to cool after the baking step. Such gaseous fluid can comprise argon having a moisture content of no greater than 10.0 ppb and an oxygen content of about 10 ppb. No improvement was seen in a sample in which nitrogen was used. When nitrogen shows no improvement, the article should be flushed with a rare gas during baking which additionally should contain 10 ppb nitrogen or less.

Stainless steel surface passivation treatment

The present invention provides a method for surface passivating stainless steel articles against the effects of corrosive materials having activities anywhere from aqueous salt solutions to corrosive gases such as hydrogen chloride and silane. Additionally, after the treatment and exposure of the article to moisture, when the article is subsequently flushed with a dry gaseous fluid, the time that the article takes to exhibit an acceptable moisture outgassing rate is reduced over an untreated article. In accordance with the present invention, the surface to be passivated is flushed with a dry gaseous fluid, chemically non-reactive with the stainless steel and containing essentially no oxygen. During such flushing, the articles is baked and cooled. The baking is accomplished at a predetermined temperature and time (preferably between about 250.0.degree. C. and 500.0.degree. C. for about 4.0 hours) to effect, within the oxide layer, a reduction in absorbed moisture and hydroxide content and an increase in chromium content. The article is allowed to cool after the baking step. Such gaseous fluid can comprise argon having a moisture content of no greater than 10.0 ppb and an oxygen content of about 10 ppb.

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New Providence, NJ, United States of America

Robert Sherman