Rust takes a rest

New corrosion-control coatings are simple to apply and better withstand harsh environments than zinc phosphating. Improved protection against rust and corrosion is one reason automakers have been able to offer longer vehicle warranties. These efforts go beyond cosmetic body panels to include hidden components such as metal-elastomer isolation and motor mounts, strut mounts, and brackets. Protecting the latter parts from environmental assault and preparing their metal surfaces to be bonded used to be complicated. Preparation entailed special, multistep (and environmentally unfriendly) processes of chemical rinses and surface treatments. MetalJacket coating system does away with all that. It instead "autodeposits" barrier coatings without high voltage, rinses, or the heavy metals of the ubiquitous zinc-phosphate plating process. Lord says MetalJacket aqueous coatings contain no hazardous, volatile organics and generate no hazardous waste or sludge. MetalJacket coatings work on clean ferrous steels, zinc-phosphated steels, or cast iron. Parts to be coated are first induction heated to remove surface contaminants. This eliminates grit blasting and the acid-pickle and alkaline-rinse steps of conventional methods. The MetalJacket process is either one or two-part, depending on the application. The first part, an autodepositing metal treatment called MetalJacket 1100, replaces the zinc-phosphating step and prepares mild steel for part two, the coating. MetalJacket 2100 coating is a low-viscosity, aqueous solution that reacts with steel surfaces to form a soft gel when parts are dipped into it. Gel deposition is driven by diffusion of iron ions at the part surface. Diffusion slows as a film builds which helps control thickness. The self-limiting process applies uniform films tens of microns thick, even on complex surfaces. Parts coming out of the coating bath are induction heated (to a lower temperature than used for cleaning) to drive off water. The coating serves two purposes: it acts as a primer for rubber-to-metal bonding and