2002 Progress Report: Zeolite Coatings by In-Situ Crystallization as an Environmentally Benign Alternative to Chromate Conversion and Anodization CoatingsEPA Grant Number: R828134
Title: Zeolite Coatings by In-Situ Crystallization as an Environmentally Benign Alternative to Chromate Conversion and Anodization Coatings
Investigators: Yan, Yushan
Institution: University of California - Riverside
EPA Project Officer: Richards, April
Project Period: August 1, 2000 through July 31, 2003 (Extended to July 31, 2004)
Project Period Covered by this Report: August 1, 2001 through July 31, 2002
Project Amount: $250,316
RFA: Technology for a Sustainable Environment (1999) RFA Text | Recipients Lists
Research Category: Nanotechnology , Sustainability , Pollution Prevention/Sustainable Development
The objective of this research project is to develop a chromium-free zeolite coating that has comparable thickness to chromate conversion and anodization coatings and equivalent or superior performance in coating adhesion, corrosion protection, abrasion resistance, and paint adhesion. We also will develop an intrinsically inexpensive, safe, and nonpolluting in-situ crystallization process that is capable of coating large surfaces with complex shape and in confined spaces. Zeolites are microporous crystalline silicate materials and have widely been exploited for their microporosity (<15Å) as catalysts and separation media. However, many high silica zeolites are nonporous in their as-synthesized state because of organic molecules that occlude in their pores during crystallization. High-silica zeolites also are known for their thermal and chemical stability and high mechanical strength. The goal of this research project is to explore these dense polycrystalline high silica or pure silica zeolite films in their as-synthesized state for corrosion protection.
In Year 1, we demonstrated that high silica zeolite ZSM-5 coatings on aluminum alloys and steel are extremely corrosion resistant in strong acids, bases, and pitting aggressive environments. We also demonstrated that the in-situ crystallization coating deposition method we developed is capable of coating surfaces of complex shape and in confined spaces-two key features of an anodization process. Also, we demonstrated that the ZSM-5 coating is an effective adhesive and has thermal shock stability. In addition, we determined that it performs reasonably well under bending and mechanical impact, and it can be easily painted with widely used polymeric paints.
In Year 2, we demonstrated that high-silica zeolite coatings are a general approach for providing corrosion protection of aluminum alloys-this is another key milestone for zeolite coating technology. We have shown that high-silica zeolite beta and zeolite MTW both provide effective corrosion resistance. In addition, a journal article on this has been published and two technical presentations have been made at the Gordon Conference and the 2002 American Institute of Chemical Engineers (AIChE) Annual Meeting. We have successfully defended our patent including both the materials and process claims. This comprehensive patent will become a key piece of intellectual property for commercialization efforts. Based on the results of this research project, our proposal in collaboration with the U.S. Navy, U.S. Army, and the University of Massachusetts in the amount of $1.65 million for 4 years has been approved by the Strategic Environmental Research and Development Program (SERDP) program. In turn, this will allow us to pursue many key issues facing technology developments.
Thus far we have focused on the aluminum alloys 2024-T3. The goal for Year 3 is to extend ZSM-5 coating to other important aluminum alloys such as the 5000, 6000, and 7000 series. If demonstrated successfully, this will be another significant step forward for the zeolite coating technology.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
|Other project views:||All 40 publications||23 publications in selected types||All 22 journal articles|
||Cheng X, Wang Z, Yan Y. Corrosion-resistant zeolite coatings by in situ crystallization. Electrochemical and Solid-State Letters 2001;4(5):B23-B26.||
||Mitra A, Wang Z, Cao T, Wang H, Huang L, Yan Y. Synthesis and corrosion resistance of high-silica zeolite MTW, BEA and MFI coatings on steel and aluminum. Journal of the Electrochemical Society 2002;149(10):B472-B478.||