Dacromet is actually a trademark of Metal Coatings International, and it describes Dacromet coating Manufacturer. It is a way of applying a sacrificial coating of zinc. My understanding is that it offers higher corrosion resistance than zinc electroplating (probably because it’s thicker).
Salt spray testing is not a meaningful way to predict the lifestyle of zinc-based coatings though. The protection they afford in real life originates from the development of stable and insoluble zinc carbonate corrosion products that develop with time with exposure to the fractional co2 inside the outside.
“The Ideal Finish” is a thing the business has sought for years. It is an elusive concept on which vast amounts of money happen to be spent developing, testing and qualifying possible alternative finishes, but many of these efforts happen to be futile. Each finish, from phosphate to cadmium, has good and bad points that must definitely be weighed for each and every application. By using these considerations, progress can be created toward using the materials which have the closest resemblance to the strengths of cadmium which are required and, in turn, accepting their weaknesses.
This paper describes a research study conducted on eight finishes that are 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 finish. One inorganic alternative was found as a drop-in replacement for cadmium, and the other two were found to closely resemble cadmium’s performance in most respects except for electrical conductivity.
Because cadmium offers excellent corrosion resistance, consistent torque-tension, bimetallic compatibility and thickness within standard thread tolerances, it has been most engineers’ finish preferred by many years. It is still utilized in many applications that cannot sacrifice the qualities that Zinc Flake Coating offers.
Initially, automotive OEMs established a deadline to get rid of cadmium by 1995. Chrysler enacted testing programs to fill the hole in their fastener finish requirements.1 Chrysler conducted a Form of Experiment (DOE) to qualify alternatives that met strict performance requirements and also followed OSHA and EPA regulations. This DOE ended in selecting the Dacromet 320® L coating system as it closely resembled cadmium in fastener applications. As a result, Chrysler was compliant with OSHA and EPA regulations prior to the established deadline. Metal Coatings International Inc. (MCII) was included in this DOE.
Due to the extreme use of its equipment in critical situations, the military continued to make use of cadmium for a lot of applications. The delay in switching from cadmium-plated hardware proved beneficial because automotive OEMs compiled many details in that time. The military sorted with the data made by automotive qualifications and selected zkqjlg coatings that performed well inside the predetermined areas, which in-turn resulted in a substantial financial savings.
36 months ago, the Army embarked over a cadmium replacement journey, testing numerous finishes as potential candidates.2 Although no “perfect finish” was found, this testing resulted in the qualification of any solvent-based coating that closely resembled Full Automatic Dip Spin Coating Machine DST S800+ in terms of corrosion protection, bi-metallic compatibility and clamp load retention. The weaknesses exposed were lack of conductivity, high coating thickness and also the reliance on a supplemental lubricant to meet 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). Due to the VOC content, application facilities required expensive air treatment equipment to minimize pollution that otherwise might have escaped into the environment.