Engineers in the aerospace, automotive, food processing, industrial, and military industries turn to solid film coatings to help solve problems which occur with fasteners, bearings, gears, valves, latch surfaces, metal-to-metal sub-assemblies, non-stick and release applications, etc. Some of the most common types of issues that engineers face are categorized and defined below:
The deterioration of surfaces is a huge problem in many industries. Wear is the result of erosion, abrasion, impact, metal-to-metal contact, oxidation, and corrosion, or a combination of these. Abrasion is the wearing of surfaces by rubbing, grinding, or other types of friction. It usually occurs due to metal-to metal contact. It is a scraping, grinding wear that rubs away metal surfaces and can be caused by the scouring action of sand, gravel, slag, earth, and other gritty material. The effects of wear can sometimes be repaired and is generally very expensive, or parts need to be replaced.
Prevention and wear protection is the most economical way to offset the high costs associated with component repair or replacement. Keeping your equipment up and running is paramount in achieving profit and customer satisfaction.
Hard-face coatings are applied to problematic wear surfaces for the purpose of reducing wear and/or the loss of material by abrasion, impact, erosion, corrosion, oxidation, cavitations, etc. In order to properly select a coating system for a specific requirement it is necessary to understand the type of wear that has occurred (or will occur) to cause surface deterioration.
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Organic and inorganic-based coating technologies create wear-resistant, liquid or vapor barriers inert to most any known compounds. These coatings are inert to most chemicals, including acids, alkalies, halogens, metal salts, solvents, and exhibit excellent corrosion resistance. Upon request, we will supply coated samples and recommend that you evaluate the coating under your specific application conditions.
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Corrosion is an electrochemical process, which involves the transfer of electrons ultimately resulting in the oxidation of the substrate. A corrosion-resistant organic coating functions by slowing down the flow of electrons and thus slowing the rate of corrosion. If the resistance of a coating to the flow of electrons can be measured, then a numerical evaluation of a coatings ability to resist corrosion can be determined.
Persistent salt-spray failure in one particular area of a fastener is cause to examine and question the materials on the part. Often a change of the cleaning chemical will remove the material. In the case of burnt-on materials, a call to the customer stating the problem and a request for an alternate cleaning method approval is in order. Acidic cleaning, stronger caustics, or even abrasive blasting may be needed in severe cases.
We are licensed to apply zinc and aluminum-rich coating systems which can exceed 1,000 hr. neutral salt spray.
References used: Paint & Coatings Magazine – Todd Roper & Charles Simpson
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It’s sometimes hard to understand how our CD players, laptop computers or cell phones could have any affect on an airplane. So, why did the airlines add this restriction? The reason is EMI and RFI, or electromagnetic interference and radio frequency interference. When electronic devices are in use, they emit electromagnetic and/or radio waves. When several electronic devices are in close proximity to each other, the waves from one device can hinder the performance of the other. Therefore, your personal electronic devices can interfere with the electronic devices that run the plane. In order to prevent EMI and RFI, electronic devices are manufactured with a shield. Shielding is a technique used to control the interference between electronic devices by preventing the transmission of electromagnetic and radio waves. Shielding can be accomplished in a variety of ways, but two of the more common methods are plating and coating. EMI and RFI shielding coatings contain metallic flakes, since the coating needs to be conductive. The metallic flakes are usually nickel, copper, silver or some combination of those metals. While using conductive coatings is a relatively inexpensive method for EMI and RFI shielding, the coatings are still quite expensive-about $125-255/gal-when compared to more common decorative paints.
References used: EMI Shielding with Turbine Power by Steven R. Kline, Jr. (Product Finishing archives)
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High-temperature resistant coatings normally contain an organic binder, silicone resin and pigments. Once these coatings have been cured and are exposed to service temperatures above 250ºC, they begin to oxidize, forming an inorganic coating. During this process, the oxidative products migrate through the film to the atmosphere as CO2 and a mixture of oxidized organic gases. If the film is too thick, the volatile materials are unable to migrate out of the film and they will build-up beneath the surface, putting stress on the film. If there is too much stress applied to the film, the coating will crack and ultimately end up delaminating. The preferred dry film thickness is less than 1 mil (25 microns).
References used: Paint & Coatings Magazine – James Greene
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We can apply metal to rubber bonding adhesives which are used on vibration-isolating mounts for computer, office, and high-speed production equipment, seals for aerospace systems, overmolded spool valves, armatures, poppet valves, plunger pins for use in pop-off valves, seals and rollers, crash stops, actuators, overmolded stators, magnetic latch assemblies for disk drives, et al.
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Coatings such as PTFE (a.k.a. Teflon®), nylon, PVC, etc. can eliminate noise/squeak from the expansion and compression of a spring. Coatings can also act as a vibration damper.
Sound dampening coatings are generally soft and elastomeric and, in the case of a spring coating, it must also be extremely flexible. Springs with a flexible liquid coating or an elastomeric polyurethane coating could help vibration dampening, noise and/or squeak reduction.
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Teflon® coatings provide excellent non-stick and mold release properties, and many are FDA compliant & USDA approved. Coatings provide contamination-free surfaces and provide easy cleaning with only water or mild detergents.
Many times ferrous or non-ferrous molds, extrusion equipment, sealing bars (used in melting plastic film in packaging operations), and valves require release or non-stick coatings. Mold release coatings are formulated with a thermoplastic resin, which bonds to your mold surface, creating a semi-permanent polymer release barrier on the surface of your composite or metal tooling. It enhances the durability characteristics, while achieving an excellent non-stick surface.
Fiberglass, rubber, plastics, composites are among the many substrates that non-stick coatings can release. Parts will not stick to release coatings because of their low surface energy, and unlike sacrificial release agents such as wax or silicone, it will not transfer to your parts.
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What is COF and why is it needed? COF is a measurement of how slippery the finish is. To those acquainted with the fastener torque calculation formula, Tq = KDL, the following is well known. The final torque of a joint (T) is the product of the torque factor (K) times the diameter of the fastener (D) times the preload (L). This K factor is further broken down into several other subfactors such as underhead friction, thread friction, tooling drag, etc. But, all of these factors rely upon the COF of the finish to some extent.
References used: Cf of Fastener Finishes by Tom Doppke (Product Finishing archives)
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Seizing and/or galling is a type of metal-to-metal contact wear that rips and tears out portions of metal surfaces. It is often caused by metal parts seizing together because of lack of lubrication. It usually occurs when the metals moving together are of the same hardness. Frictional heat promotes this type of wear. Galling can occur when metal parts, such as the threads of nuts and bolts, are forced together and rubbing generates friction among the asperities (high spots) on the surface. The friction causes heat, which is mainly isolated to these asperities. The asperities weld together but further displacement causes these tiny welds to break, which makes the surface even rougher, creating more opportunity for friction.
The tendency for metal to seize or gall when in sliding contact with itself or with other alloy materials can be reduced with the use of dry film lubricants. This is particularly desirable for bearing surfaces and for threads of bolts. Dry film lubricant coatings reduce the galling tendency and are effective in preventing seizure of bolt threads.
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