System approach interface engineering

The proper execution of system approach interface engineering (SAIF) requires the understanding of fundamentals of the interface. Conversely, utilization of nanofilms of unique plasma polymers provided tools to investigate the fundamentals of interfaces, which were nearly impossible to examine otherwise. The use of LCVD in the interface engineering and the basic investigation of interface worked hand in hand to broaden the knowledge in this specific topical area. 

I. SYSTEM APPROACH INTERFACE ENGINEERING FOR CORROSION PROTECTION... 

In this chapter, corrosion protection of metal is used to illustrate the importance of interfacial factors and the role of system approach interface engineering. When a coating is applied in order to protect a substrate, the factors, particularly interfacial factors demonstrated by examples of corrosion protection, play important roles regardless of the nature of protection to be accomplished. An excellent coating cannot function well with poor interfaces. The creation of stronger interface is the core of SAIE. 

Parylene C film could be utilized in system approach interface engineering (SAIE) if the adhesion of Parylene C film to the substrate and the adhesion of a eoating, whieh is applied on the surface of Parylene C, could be improved. The seheme of utilizing Parylene C film in SAIE is depicted in Figure 30.7. Methods to improve its adhesion have been developed, but improvement is limited due to the lack of specific chemical interactions in the interfaee [13]. Low-temperature plasma deposition has proved to be a very effeetive proeess in improving the adhesion properties of materials while maintaining their desirable bulk properties. 

An ultrathin layer of plasma polymer of trimethylsilane (TMS) has been utilized in the corrosion protection of aluminum alloys by means of system approach interface engineering (SAIE) [1 ]. SAIE by means of low-temperature plasmas utilizes low-temperature plasma treatment and the deposition of a nanolilm by luminous chemical vapor deposition (LCVD). This approach does not rely on the electrochemical corrosion-protective agents such as six-valence chromium, and hence the process is totally environmentally benign. 

System approach interface engineering (SAIE) by means of low-pressure plasma in corrosion protection of metals was first applied on cold-rolled steel (CRS) [1-3]. Unlike aluminum alloys described in the previous chapters, oxides on the surface of steel and iron are less stable than those on aluminum alloys, i.e., iron oxides formed on the surface do not have corrosion protecting capability of iron underneath and hence are more vulnerable for corrosion. On the other hand, the oxides on the surface of steel can be removed by plasma treatment, particularly of (Ar- -H2) plasma. Hence, SAIE could be performed in totally dry processes. The improvement of corrosion protection by means of environmentally benign process was the motivation for the approach. 

Reddy, C. M., Yu, Q. S., Mofiitt, C. E., Wiehczka,D. M., Johnson, W., etal. 2000. Improved corrosion protection of aluminum aUoys by system approach interface engineering Part 1 - Alclad 2024-T3. Corrosion, 56, 819-831. 

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