Hexafluorozirconic Acid Based Surface Pretreatments: Characterization and Performance Assessment
- Ohio State University
- ORNL
- Henkel Corp
A new phosphate-free pretreatment from Henkel Corp. named TecTalis , was investigated. The treatment bath is composed of dilute hexafluorozirconic acid with small quantities of non-hazardous components containing Si and Cu. The performance of treated steel was compared to samples treated in a phosphate conversion coating bath, in simple hexafluorozirconic acid and in TecTalis without the addition of the Cu containing component. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) were used to characterize the coating surface morphology, structure and composition. A Quartz Crystal Microbalance (QCM) was used for studying film growth kinetics on thin films of pure Fe, Al and Zn. Electrochemical Impedance Spectroscopy (EIS) was performed on treated and painted steel for studying long-term corrosion performance of the coatings. The phosphate-free coating provided long-term corrosion performance comparable to that of phosphate conversion coatings. The coatings uniformly cover the surface in the form of 10-20 nm sized nodules and clusters of these features up to 500 nm in size. The coatings are usually about 20-30 nm thick and are mostly composed of Zr and O with enrichment of copper at randomly distributed locations and clusters.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 986798
- Journal Information:
- Electrochimica Acta, Journal Name: Electrochimica Acta; ISSN 0013-4686
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ATOMIC FORCE MICROSCOPY
COATINGS
COPPER
CORROSION
IMPEDANCE
KINETICS
MICROBALANCES
MORPHOLOGY
PERFORMANCE
PHOSPHATES
QUARTZ
SPECTROSCOPY
STEELS
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
surface pretreatment
phosphate conversion coating
cold rolled steel
corrosion protection
zirconium