The importance of fastener coatings is becoming more apparent throughout the wind industry. Different coating chemistries have been used to improve corrosion protection, or lubricity, or both. However, increasing demands on field life, global legislation, and worldwide commonization continue to create challenges for many traditional coatings. A thorough understanding of a fastener’s coating performance can ensure joint integrity, as well as improve field life and serviceability. Global acceptance and availability are also key considerations in choosing the right coatingMolybdenum Disulfide Coatings (MoS2 coatings) , also known as Moly Coatings are commonly used in applications where load carrying capacity, operating temperature and coefficient of friction are primary concerns. This coating provides effective lubrication in a wide range of loads, in many cases exceeding 250,000 psi. Moly coatings lubricate sacrificially by transferring lubricant between the two mating surfaces, which helps to reduce wear and coefficient of friction. Molybdenum Disulfide (MoS2) coatings are a dry film lubricant.Xylan® Coatings are a family of fluoropolymer coatings designed for use on various types of OEM components and fasteners, including xylan coated bolts to prevent corrosion. Most Xylan® coatings contain PTFE or other types of lubricants and are applied in thin films. Xylan coating is a dry film lubricant.Molybdenum Disulfide Coatings (MoS2 coatings) , also known as Moly Coatings are commonly used in applications where load carrying capacity, operating temperature and coefficient of friction are primary concerns. This coating provides effective lubrication in a wide range of loads, in many cases exceeding 250,000 psi. Moly coatings lubricate sacrificially by transferring lubricant between the two mating surfaces, which helps to reduce wear and coefficient of friction. Molybdenum Disulfide (MoS2) coatings are a dry film lubricant.Thermal epoxy cure coatings are specially blended high molecular weight coatings which provide outstanding corrosion resistance in most environments. These thermally conductive epoxy coatings are also ideal for applications where an abrasion resistant coating is needed and often used as primers to improve the adhesion of coatings on metal surfaces. Thermal epoxy cure coatings offer excellent barrier protection from alkali and caustic solution and other harsh chemicals and solvents.Inorganic Zinc coatings when applied to blasted steel provide excellent anti-rust spray coating corrosion protection, weathering protection, and very good resistance to salt water and resistance to solvents. Inorganic zinc coatings provide excellent anti-rust corrosion protection when used in chemical plants, refineries, and coastal or offshore installations. This coating can provide even better corrosion protection when a topcoat is applied. Inorganic zinc coatings is compatible with epoxies, phenolics, acrylics, silicone’s, and many other coatings.Phenolic coatings offer consistent high quality protection for a wide range of applications including immersion service for most acids, solvents, and salts. This epoxy phenolic coating is typically used where low pH environments and higher temperatures are factors. These coatings have excellent resistance to 92% – 98% sulfuric acid at temperatures up to 120°F. Phenolic coatings are also resistant to hydrochloric acid, phenol, anhydrous chlorobenzene, carbon tetrachloride, and many other chemicals.Phosphate coatings are a crystalline conversion coating that is formed on a ferrous metal substrate. Phosphate coating is employed for the purpose of pretreatment prior to coating or painting, increasing corrosion protection and improving friction properties of sliding components. In other instances, phosphate coatings are applied to threaded parts and top coated with oil (P&O) to add anti-galling and rust inhibiting characteristics.
The phosphating process relies on the basic pickling reaction that occurs on the metal substrate when the process solution comes in contact with the metal. The main benefits that phosphating provides is strong adhesion and corrosion protection. Typically, phosphate coatings used on steel parts but can also be used on aluminumThe importance of corrosion protection and lubricity in the wind industry differs from the building trades or the appliance industry. Varying demands have made it impossible to formulate one universal coating. A short list of what a coating should do includes

Alodine® EC2™ is a revolutionary electroceramic coating that remains fully intact on the fastener, even after installation, resulting in superior protection. Alodine EC2 provides corrosion protection for fasteners used in:This is of lesser concern in most turbine joints, but it plays a key role when choosing a fastener coating in the building trades and appliance industry. Electroplated and electrocoated fasteners are predominant in these industries. Because such fasteners are often visible, it is essential to match colors and coat uniformly. Electroplated fasteners offer good uniformity and come in several different colors using different passivation systems, dyes, and a topcoat. Electrocoated fasteners also offer good uniformity but are typically available only in blackIdentifying a coating with the right frictional characteristics is probably the most crucial task. Erratic friction during assembly leads to either a loose joint or too much strain on the fastener. Either event can lead to a failed joint. Two important components of lubricity are consistency and efficiency. Both are required to insure joint integrity and easy assembly. Proper lubricity assists the fasteners’ ability to efficiently reach its designed load at a prescribed torque. The torque-tension graphs (next page) demonstrate how properly integrated lubrication can improve joint consistency. Some alloy platings also have improved lubricity but are typically more expensive than zinc plate or dip and spin coating.