Dacromet is a trademark of Metal Coatings International, and it describes Dacromet coating Manufacturer. This is a way of applying a sacrificial coating of zinc. My understanding is that it gives higher corrosion resistance than zinc electroplating (probably because it’s thicker).
Salt spray tests are not just a meaningful method to predict the lifestyle of zinc-based coatings though. The safety they afford in the real world arises from the formation of stable and insoluble zinc carbonate corrosion products which develop with time with being exposed to the carbon dioxide within the open air.
“The Perfect Finish” is a thing the market has sought for many years. It is really an elusive concept which vast amounts of money have been spent developing, testing and qualifying possible alternative finishes, but the majority of these efforts have already been futile. Each finish, from phosphate to cadmium, has strengths and weaknesses that must be weighed for each application. By using these considerations, progress can be made toward using the materials that have the closest resemblance for the strengths of cadmium which can be required and, subsequently, accepting their weaknesses.
This paper describes an investigation study conducted on eight finishes which can be potential replacements for cadmium. Information and facts are specific to fasteners with regards to clamp load and corrosion, both cosmetic and galvanic. The scope was broadened to comprehend many elements of each finish to give engineers information vital to recommending their use as cadmium substitutes and exposing weaknesses of each and every finish. One inorganic alternative was discovered to be a drop-in alternative to cadmium, and another two were found to closely resemble cadmium’s performance in most respects aside from electrical conductivity.
Because cadmium offers excellent corrosion resistance, consistent torque-tension, bimetallic compatibility and thickness within standard thread tolerances, it really has been most engineers’ finish of choice for many years. It really is still found in many applications that cannot sacrifice the qualities that Zinc Flake Coating offers.
Initially, automotive OEMs established a deadline to eliminate cadmium by 1995. Chrysler enacted testing programs to fill the hole in its fastener finish requirements.1 Chrysler conducted a Design of Experiment (DOE) to qualify alternatives that met strict performance requirements as well as adhered to OSHA and EPA regulations. This DOE resulted in selecting the Dacromet 320® L coating system since it closely resembled cadmium in fastener applications. As a result, Chrysler was compliant with OSHA and EPA regulations before the established deadline. Metal Coatings International Inc. (MCII) was associated with this DOE.
Because of the extreme use of its equipment in critical situations, the military continued to use cadmium for many applications. The delay in switching from cadmium-plated hardware proved beneficial because automotive OEMs compiled many details during that time. The military sorted with the data created by automotive qualifications and selected zkqjlg coatings that performed well inside the predetermined areas, which in-turn resulted in a substantial financial savings.
Three years ago, the Army embarked on the cadmium replacement journey, testing numerous finishes as potential candidates.2 Although no “perfect finish” was found, this testing ended in the qualification of any solvent-based coating that closely resembled Full Automatic Dip Spin Coating Machine DST S800+ in relation to corrosion protection, bi-metallic compatibility and clamp load retention. The weaknesses exposed were absence of conductivity, high coating thickness as well as the dependence on a supplemental lubricant to fulfill Army torque charts. Another attribute that must definitely be considered is that this coating was solvent-based and thus rich in volatile organic compounds (VOC). Because of the VOC content, application facilities required expensive air treatment equipment to minimize pollution that otherwise might have escaped into the environment.