Environmentally Compliant Corrosion Resistant Electrically Conductive Inorganic Coatings For Aluminum Alloys
DOWNLOAD
Download Environmentally Compliant Corrosion Resistant Electrically Conductive Inorganic Coatings For Aluminum Alloys PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Environmentally Compliant Corrosion Resistant Electrically Conductive Inorganic Coatings For Aluminum Alloys book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
Environmentally Compliant Corrosion Resistant Electrically Conductive Inorganic Coatings For Aluminum Alloys
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2001
Environmentally Compliant Corrosion Resistant Electrically Conductive Inorganic Coatings For Aluminum Alloys written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
The objective of this project was to develop an environmentally compliant conversion coating for use on aerospace aluminum alloys (e.g., AA2024-T3). This conversion coating was to replace the current chromate conversion coating processes in both mode of application (bath or spray applied in the depot) and function (stand alone corrosion protection, adhesion to organic layers, self-healing, and low electrical contact resistance). Hydrotalcite (HT) was developed within this program as a replacement to chromate conversion coatings. HT coatings are formed by exposure of aluminum and its alloys to alkaline lithium salt solutions. The coating chemistry used to form these conversion coatings has many processing variables (e.g., time, temperature, anion, etc.). A Fractional Factorial Design was used to determine that temperature was one the more critical processing variables. The FFD study also determined that HT coatings formed from nitrate-based chemistries had consistently better stand-alone corrosion protection properties. Through the use of additional oxidants within the coating bath, HT coatings with the ability to withstand 168 hours of salt spray could be formed in less than 6 min. HT conversion coatings could also be post-treated (e.g., hydrothermally aged, surfactant) to revert the hydrotalcite to aluminum oxide, or augmented to include high valence-state rare earth cations (e.g., cerium). Hydrothermal aging allowed a procedure to chemically anodize aluminum, while incorporation of cerium into the molecular gallery of the hydrotalcite structure provided a means to develop self-healing characteristics, a highly sought property characteristic of chromate-based coatings. Self- healing was indeed demonstrated by the cerium doped HT coatings. The adhesion of epoxy coatings to the hydrotalcite coating was studied in detail. The Lewis-base nature of HTs makes them intrinsically less able to be wet by the Lewis- base nature of epoxy.
Organic Inorganic Hybrid Sol Gel Coatings As Eco Friendly Surface Pretreatment For Corrosion Protection Of Aluminum Alloy
DOWNLOAD
Author : Mahshid Niknahad
language : en
Publisher:
Release Date : 2016
Organic Inorganic Hybrid Sol Gel Coatings As Eco Friendly Surface Pretreatment For Corrosion Protection Of Aluminum Alloy written by Mahshid Niknahad and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Alloys categories.
Pretreatments are thin, adherent, and protective layers deposited directly on cleaned metal surfaces to enhance the performance of the multi-coat finishing system on metal and alloy substrates. Regulatory and environmental considerations dictate that industries replace the extant toxic and hazardous chromate-based pretreatments used for aluminum alloys with more sustainable ones. Two new families of organic-inorganic hybrid (OIH) pretreatments for aluminum alloys have been developed using customized silane-type sol-gel precursors--Epoxy-silane and Bis-ureasil--as primary components. Two series of sol-gel compositions varying in concentrations of silane precursor, organic corrosion inhibitor, and nano-silica particles have been prepared and used to deposit OIH pretreatments on aluminum alloy substrates (AA-2024-T3). The corrosion resistance performance of these OIH pretreatments has been studied by electrochemical impedance spectroscopy (EIS), direct current (DC) polarization resistance, and neutral salt spray test and compared with the resistance performance conventional hexavalent chromium-based pretreatment, as a benchmark and industry standard for Al alloys. This research specifically investigates the effects of key components of sol-gel compositions on the corrosion performance of the OIH pretreatments on Al-2024-T3. Using the Box-Behnken Design of Experiment (DoE) methodology and Minitab software for analysis, the key factors affecting corrosion performance have been identified and sol-gel compositions optimized. This study revealed that for both families of OIH pretreatments, the film deposited in the sol-gel bath containing 25% by weight of precursor provided the best performance. Furthermore, incorporation of nano-silica particles to an optimum level of 5% by weight led to a remarkable improvement of the corrosion-resistance performance of the pretreatments for both families. This study has also very clearly shown that the use of the organic corrosion inhibitor mercaptobenzthiazole is effective in enhancing the corrosion-resistance performance of both families of pretreatments when used at the optimum level of 3% by weight. A comparison of the corrosion-resistance performance of the two families of OIH pretreatments with chromate conversion coating (control) showed that pretreatments based on epoxy-silane precursor when used at optimum compositions clearly outperform chromate conversion coatings used as a control in this study. Furthermore, OIH based on a bis-ureasil precursor, while showing a slightly lower performance than its epoxy-silane counterpart, is comparable or slightly superior to the commercial conversion coating when used at optimum compositions.
Environmentally Friendly Rare Earth Based Inhibitors In Conversion Coatings And Paint For The Corrosion Protection Of Aluminum Alloys
DOWNLOAD
Author : Scott A. Hayes
language : en
Publisher:
Release Date : 2005
Environmentally Friendly Rare Earth Based Inhibitors In Conversion Coatings And Paint For The Corrosion Protection Of Aluminum Alloys written by Scott A. Hayes and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Aluminum alloys categories.
"Aluminum alloys such as 7075-T6 and 2024-T3 are commonly used in aircraft because of their strength to weight ratio. While the mechanical properties of these alloys are very good, they are particularly susceptible to corrosion. Coatings are commonly used to protect these aluminum alloys to corrosive attack. One type of coating, called a conversion coating, is a thin, inorganic film normally deposited directly on the bare metal surface. The other types of coatings, generically referred to as paints, include primers which are applied over a conversion coating. A primer consists of a binder, usually organic, and pigments, which are mostly inorganic particles dispersed in the binder. Part of the primer's pigment content includes compounds that can provide corrosion protection. For the corrosion protection of aluminum, the most commonly used conversion coating and primer pigments contain Cr(VI) compounds. While highly effective, Cr(Vl) compounds are becoming undesirable due to their increasingly recognized toxicity and the greatly increased handling costs due to the health threat that they pose. For these reasons, much research has been conducted in recent years to find alternatives to chromates. The central purpose of the thesis work presented herein was to develop non-chromated conversion coatings and primers. To support this effort, the fundamental chemistry of cerium, a potential chromium replacement, was studied. Also undertaken was the development of a methodology for using the scanning vibrating electrode technique (SVET) to characterize pretreatments and coatings. As a consequence of this study, five patent applications were filed as well as numerous papers and reports"--Abstract, leaf iv.
Corrosion Protection Of Aluminum Alloys Used In Aircraft Testing Analysis And Development Of Environmentally Compliant Coatings And Pretreatments For The Corrosion Protection Of Aircraft Alloys
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2002
Corrosion Protection Of Aluminum Alloys Used In Aircraft Testing Analysis And Development Of Environmentally Compliant Coatings And Pretreatments For The Corrosion Protection Of Aircraft Alloys written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with categories.
This report describes the work for FY 2000 for the Project Corrosion Protection of Aluminum Alloys Used in Aircraft (Grant # F49620-99-1.0283) for AFOSR. This Report contains the following sections that address the technical goals of the project: Goal 1. Improved electrochemical test methods and protocols for characterizing the performance of coated aircraft alloys. Goal 2. Surface Analysis Studies of Degradation of Coatings Properties Goal 3. SVET Studies of Coated Aluminum Alloys Goal 4. Advanced Spectroscopy of Coating/Metal Systems Goal 5. Further examination of conductive polymers for chrome free metal pretreatment primers for Al alloys Goal 6. Development of molecular probes for examining changes in thin coating films during exposure Goal 7. Electrochemical Instrumentation Development Goal 8. Chrome-free pretreatment materials based on sol-gel optimization - new silicon oligomer design & synthesis Goal 9. Improved design/expert systems methods for total aircraft coatings systems design (with AFRL/WPAFB).
Aging Of U S Air Force Aircraft
DOWNLOAD
Author : National Research Council
language : en
Publisher: National Academies Press
Release Date : 1997-09-30
Aging Of U S Air Force Aircraft written by National Research Council and has been published by National Academies Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997-09-30 with Technology & Engineering categories.
Many of the aircraft that form the backbone of the U.S. Air Force operational fleet are 25 years old or older. A few of these will be replaced with new aircraft, but many are expected to remain in service an additional 25 years or more. This book provides a strategy to address the technical needs and priorities associated with the Air Force's aging airframe structures. It includes a detailed summary of the structural status of the aging force, identification of key technical issues, recommendations for near-term engineering and management actions, and prioritized near-term and long-term research recommendations.
Environmentally Compliant Coatings Using Non Chromated Systems
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2001
Environmentally Compliant Coatings Using Non Chromated Systems written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2001 with categories.
Conversion coatings and primers used for the corrosion protection of aluminum alloy components in aircraft are based, almost exclusively, on chromate systems that are on the Environmental Protection Agency List of hazardous materials. Chromium is targeted for elimination from the workplace. This effort is part of a research program to develop a suitable replacement for chrome in coatings technology. This effort focused on the use of cerium chemistry to provide the corrosion inhibition for aluminum alloys used in the aircraft industry. The primary tasks were the development of a non-chromated conversion coating and surface treatment and a non-chromated primer coating system for military aircraft. This report presents the development, characterization, and evaluation of inorganic coatings that can serve as potential replacements for current chromate coatings. This effort was performed by the Materials Research Center at the University of Missouri-Rolla and the Boeing Corporation.
Processing And Properties Of Environmentally Friendly Corrosion Resistant Hybrid Nanocomposite Coatings For Aluminum Alloy Aa2024
DOWNLOAD
Author :
language : en
Publisher:
Release Date : 2005
Processing And Properties Of Environmentally Friendly Corrosion Resistant Hybrid Nanocomposite Coatings For Aluminum Alloy Aa2024 written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with categories.
Environmentally friendly sol-gel nanocomposite coatings have been processed and characterized for corrosion protection of aerospace alloy AA2024-T3. The hybrid nanocomposite coatings were processed in solution using acid-catalyzed hydrolysis and condensation of precursors Glycidoxypropyl trimethoxysilane (GPTMS) and Tetramethoxysilane (TMOS) forming self assembled nanoscale composite followed by curing using a one step and a two step process. Nanometer scale montmorillonite clay, Cloisite 15A was dispersed in the precursor solution prior to film coating. The structure and composition of the hybrid coatings was determined using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction Spectrometry (XRD). Hydrolysis and condensation kinetics were tracked using FTIR and a semi-quantitative equation was developed. Viscosity studies performed to understand the rheology of the hybrid nanocomposite, shows two distinct regimes for hydrolysis and curing. XRD results indicate a physical structure that is mostly amorphous with selective crystalline regions due to siloxane bridge formations. The Cloisite 15A clay was exfoliated, as determined by the disappearance of clay peak. Atomic Force Microscopy (AFM) was used to study the surface morphology, showing increase in surface roughness with the addition of clay. Corrosion performance was determined using DC Polarization and Electrochemical Impedance Spectroscopy (EIS). The DCP results were used to determine the optimal composition of the hybrid nanocomposite and optimal time of reaction for the first layer. The corrosion current and hence the corrosion rate for the two-step system was around three orders of magnitude lower than the one-step system, with the corrosion potential being correspondingly higher. EIS results show that the two-step system has a corrosion resistance two orders of magnitude higher than the mono-layer. The impedance was in the order of E+6 Ohms, which remained consistent over 8 weeks of testing, with a low water uptake of around 20%. Modification of the coating with diamine curing agent and clay provided significantly better results with higher resistance (E+6 Ohms) and water uptake values as low as 3-5% over 6 weeks.
Intelligent Coatings For Corrosion Control
DOWNLOAD
Author : Atul Tiwari
language : en
Publisher: Butterworth-Heinemann
Release Date : 2014-10-25
Intelligent Coatings For Corrosion Control written by Atul Tiwari and has been published by Butterworth-Heinemann this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-10-25 with Science categories.
Intelligent Coatings for Corrosion Control covers the most current and comprehensive information on the emerging field of intelligent coatings. The book begins with a fundamental discussion of corrosion and corrosion protection through coatings, setting the stage for deeper discussion of the various types of smart coatings currently in use and in development, outlining their methods of synthesis and characterization, and their applications in a variety of corrosion settings. Further chapters provide insight into the ongoing research, current trends, and technical challenges in this rapidly progressing field. Reviews fundamentals of corrosion and coatings for corrosion control before delving into a discussion of intelligent coatings—useful for researchers and grad students new to the subject Covers the most current developments in intelligent coatings for corrosion control as presented by top researchers in the field Includes many examples of current and potential applications of smart coatings to a variety of corrosion problems
Investigations Of Conductive Polymer Coatings For Corrosion Protection Of Aluminum Alloys
DOWNLOAD
Author : Robert James Racicot
language : en
Publisher:
Release Date : 1997
Investigations Of Conductive Polymer Coatings For Corrosion Protection Of Aluminum Alloys written by Robert James Racicot and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1997 with Aluminum categories.
Evaluation Of Alternative Methods For Surface Preparation And Deposition Of Cerium Based Conversion Coatings On Aluminum Alloys
DOWNLOAD
Author : William J. Gammill
language : en
Publisher:
Release Date : 2010
Evaluation Of Alternative Methods For Surface Preparation And Deposition Of Cerium Based Conversion Coatings On Aluminum Alloys written by William J. Gammill and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Aluminum coatings categories.
"This thesis investigates alternative surface preparation and deposition methods for cerium-based conversion coatings (CeCC) on high strength aluminum alloys. Cerium-based conversion coatings are being investigated as a more environmentally friendly replacement for chromium-based conversion coatings. Currently, the alloys are immersed in strong alkaline and acidic solutions to prepare the aluminum surfaces for conversion coating, in which immersion may not be suitable for all situations. Alternatives to this method were investigated, including wipe application of solution, ultrasonic processing in deionized water, and abrasive blasting with alumina. Al 7075-T6 test panels were prepared using each of these methods and compared to a