Stainless steel surface passivation treatment

Chemistry: electrical and wave energy – Processes and products – Electrostatic field or electrical discharge

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

204140, 148280, 148286, 148606, C25F 324

Patent

active

052599353

ABSTRACT:
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.

REFERENCES:
patent: 2257668 (1941-09-01), Gottfried
patent: 3247086 (1966-04-01), Goldstein
patent: 3287237 (1966-11-01), Wilton
patent: 3490958 (1970-01-01), Robinson, Jr.
patent: 4033274 (1977-07-01), Beese
patent: 4772337 (1988-09-01), Kesten
patent: 5009963 (1991-04-01), Ohmi et al.
patent: 5167735 (1992-12-01), Jurmann
Tomari, et al. "Metal Surface Treatment for Semiconductor Equipment Oxygen Passivation Solid State Technology" Feb. 1991 pp. S1-S5.
Miayauchi et al. "Proceedings of the 31st Joint Lecture Meeting on Vacuum" p. 34.
Asami et al. "Changes in the Surface Compositions of Fe Cr Allovs Caused by Heating in a High Vacuum" Corrosion Science vol. 18.
Hultquist et al. "Highly Protective Films on Stainless Steels" Materials Science and Engineering vol. 42 1980 pp. 199-206.
Adams A Review of the Stainless Steel Surface J Vac Sci Technol. vol. A 1 (1) 1983 pp. 12-18.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Stainless steel surface passivation treatment does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Stainless steel surface passivation treatment, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stainless steel surface passivation treatment will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-1140185

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.