By Chris Holland, Tom Klopack And Don Costa, Raychem Corporation
Bar metal connectors can be susceptible to corrosion especially in humid and saline environments. Various methods of cold-applied corrosion protection are available - silicone grease, pain-on coatings, mastics, self-fusing tape and gel-based sealant strip.
Some simple lab tests can be used to evaluate their comparative corrosion performance, and their respective effectiveness compared with no protection.
The paper describes 1) test sample preparation, including sources for materials. Sample range from thin metal films, metal discs, and wrapped metal bars, to connectors installed on short cable lengths. 2) how to calculate a corrosion rate for carefully prepared samples. 3) corrosion rates and other data for several methods of protection in various environments. These environments are: ASTM artifical seawater at 60degC, 5% sodium chloride solution, ASTM salt fog, "CASS" accelerated salt fog, and weatherometer (combined UV and water spray) exposure.
Other factors relating to product lifetime should also be considered when selecting a corrosion protection product. This paper focuses on corrosion performance as a key factor. All of the corrosion environments described require relatively long-term testing. The fastest method is 60degC seawater - which can be set up at low cost, using simple samples, to give a good comparison between various corrosion protection products