Title page for ETD etd-08262003-164704


Type of Document Dissertation
Author Zhang, Jinming
Author's Email Address jizhang2@vt.edu
URN etd-08262003-164704
Title Development of Environmentally Friendly Non-Chrome Conversion Coatings for Cold-Rolled Steel
Degree PhD
Department Mining and Minerals Engineering
Advisory Committee
Advisor Name Title
Yoon, Roe-Hoan Committee Chair
Gandour, Richard D. Committee Co-Chair
Adel, Gregory T. Committee Member
Luttrell, Gerald H. Committee Member
Novak, Thomas Committee Member
Keywords
  • Salt Spray Test
  • Carboxylic Acid
  • Corrosion
  • Self-Assembled Monolayer
  • Resin
  • Organic Coating
  • Thiol
  • Steel
Date of Defense 2003-07-30
Availability unrestricted
Abstract
Steel producers use various organic and inorganic coatings to protect cold-rolled steel (CRS) sheets from corrosion during shipment and storage. It is well known that CRS sheets can be protected from corrosion by galvanizing, phosphating, chromating, topcoating with organic, or their combinations. The chromate rinsing is particularly effective for preventing white rusting of galvanized steel. But there is an increasing interest in a replacement for the chromating process because of environmental and health concerns. The objective of the present work is to develop a chrome-free conversion coating for steel sheets.

Various carboxylic acids and their salts have been studied for coating phosphated electrogalvanized (EG) steel sheets, including 10-undecenoic acid (UA), oleic acid (OA), and other fatty acids such as stearic acid (SA) and palmitic acid (PA). When they were used alone, or subsequently coated with resin, they could produce a highly hydrophobic surface and improve the corrosion resistance.

Thiols such as 1-octadecanethiol (ODT) can form a self-assembled monolayer on metal substrates. This close-packed monolayer could provide an excellent corrosion resistance for EG steel sheets. It was capable of withstanding 50~60 hours of salt spray test (SST) although its thickness was only a few nanometers. The EG steel itself usually started rusting only after 2~4 hours of salt spray.

In another coating system, thiols were mixed with a conventional resin to improve the corrosion resistance of EG steel. This new technique gave 100~120 hours of corrosion resistance. When the resin was applied directly on EG steel surface, its corrosion resistance was less than 72 hours. It was shown that further optimization of this technique increased the corrosion resistance to 200 hours and more in the standard SST.

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  Acknowledgments.pdf 54.79 Kb 00:00:15 00:00:07 00:00:06 00:00:03 < 00:00:01
  Chapter1.pdf 931.83 Kb 00:04:18 00:02:13 00:01:56 00:00:58 00:00:04
  Chapter2.pdf 623.77 Kb 00:02:53 00:01:29 00:01:17 00:00:38 00:00:03
  Chapter3.pdf 1.19 Mb 00:05:31 00:02:50 00:02:29 00:01:14 00:00:06
  Chapter4.pdf 1.13 Mb 00:05:14 00:02:41 00:02:21 00:01:10 00:00:06
  Chapter5.pdf 92.60 Kb 00:00:25 00:00:13 00:00:11 00:00:05 < 00:00:01
  Contents.pdf 284.50 Kb 00:01:19 00:00:40 00:00:35 00:00:17 00:00:01
  Title-Abstract.pdf 79.56 Kb 00:00:22 00:00:11 00:00:09 00:00:04 < 00:00:01
  Vita.pdf 52.07 Kb 00:00:14 00:00:07 00:00:06 00:00:03 < 00:00:01

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