Duck Joo Yang

Interface-Engineered Parylene C Coating for Corrosion Protection of Cold-Rolled Steel

Abstract Vacuum-deposited poly(chloro-p-xylylene), or parylene C, can be used for corrosion protection of cold-rolled steel (CRS) through interface engineering. Interface engineering replaces galva...

Plasma treatment of automotive steel for corrosion protection – a dry energetic process for coatings

Abstract In the thrust of pursuing new environmentally friendly technology for automotive application, a new corrosion protection coating system for automotive steel has been developed through interface engineering affected by an energetic plasma process. The plasma treated coating system outperformed the current phosphated galvanized steel system in scab corrosion tests. In the plasma process, the steel substrate was subjected to plasma cleaning and in situ plasma polymerization deposition. Plasma of a mixture of argon and hydrogen was created to remove the surface contaminants and the inherent oxide layer. A very thin film (50–100 nm) was then deposited by a plasma generated from alkylsilanes (e.g. trimethylsilane (TMS)). The interface can be so designed that strong corrosion-resistant interfacial bonds such as Fe–Si, Fe–C, and Si–C can be obtained. The interfacial chemistry involved in the plasma process and corrosion reaction are characterized by reflection absorption infrared spectroscopy (RAIR), X-ray photoelectron spectroscopy (XPS), and sputter neutral mass spectroscopy (SNMS).

Preparation and in-situ characterization of polycarbosilane thin films by d.c. plasma-enhanced deposition

Polycarbosilane thin films were deposited using a d.c. plasma process, taking advantage of the high deposition rate and self-healing process of d.c. discharge polymerization on a conductive substrate such as steel. A unique deposition and surface analytical system was designed and constructed to deposit and analyze the polymer films in situ. The steel substrate, exposed to argon and hydrogen plasma, was found to be essentially free of carbon and oxygen. In-situ X-ray photoelectron (XPS) analysis of the initial stage plasma deposition provided evidence of chemical bonding between the steel substrate and plasma-deposited polypolycarbosilane film. An air-ageing test of the plasma polycarbosilane film showed only surface oxidization. However, incorporation of oxygen into the starting gas composition resulted in fully oxygenated polymer films. Film structure and properties were characterized by XPS and Fourier transform infrared spectroscopy.

Morphology of Phosphate Layer Investigated by Vacuum Depositing a Parylene C Film

Abstract Poly(monochloro-para-xylylene), or parylene C, was used to investigate the morphology of phosphates deposited on cold-rolled steel (CRS) and galvanized cold-rolled steel (GCRS). Vacuum dep...

The effect of cleaning procedures on surface charging of various substrates

Contact electrification occurs when two dissimilar materials are brought into contact, Each surface is left positively or negatively charged depending on the relative difference between surface state electron density in each material. A technique is described which measures the current generated when two solid surfaces are abruptly brought into contact and the current that results when they are subsequently separated. The theory of metal-insulator contacts forms the basis for this unique measurement. The technique allows measurement of surface charging of a variety of substrates after immersion in solvents used in routine semiconductor wafer cleaning and deionized water (DI) rinsing. Quantitative results are used to describe the effect of cleaning on generation of surface charge. Advantages of this technique are its simplicity and the fact that the measurement requires much less time than conventional charge measurement techniques, All the substrates in this study were significantly charged by immersion in deionized water. Charging due to immersion in isopropyl alcohol (IPA) was significantly lower than charging due to immersion in deionized water. Surface charging after immersion in other solvents could be reduced or eliminated by making isopropyl alcohol the final rinsing agent. >