powder coating pretreatment

Anodic Coatings Anodic coatings for the protection of iron and steel substrates are almost entirely limited to zinc and aluminium coatings or their alloys. Where coatings anodic to the substrate are applied, the corrosion protection is referred to as cathodic protection or sacrificial protection. The substrate is made to be the cathode and the coating the sacrificial corroding anode. The mechanisms of corrosion protection inferred by these coatings fall into two classes: Cathodic or sacrificial protection A barrier to theRead More …

Protecting Metals from Corrosion Ideally, a material which is inherently resistant to its service environment, meets with the mechanical, formability and economic requirements would be the first choice for selection. Unfortunately, this is not often the case. Many materials will need a method of corrosion control and there are three main approaches: Modification of the environment to which the material is exposed Electrical methods of control Use of protective coatings Thermal Spray Coatings for Corrosion Protection Thermal spray coatings areRead More …

Abradable coatings are designed to preferentially abrade when contact is made with a mating part. Thermal spray abradable coatings have low structural integrity so they are readily abraded when they come into contact with a moving surface with higher structural integrity. The coatings are designed not to damage the mating surface. There are a number of different abradable coating types, to cater for different operating temperatures, corrosive environments and mating materials. The coating structure can be either: 1.Very porous withRead More …

Stainless steel (SS) is relatively free of the iron hydrates that are a common component on the surface of regular grades of carbon steel.SS should be cleaned to remove the surface oils and dirt from manufacturing and handling. Many stainless steel products do not have a protective coating because they are not sensitive to ordinary atmospheric conditions. The passive oxide layer on stainless steel is relatively inert to alkaline cleaners and other chemical products that are commonly used on carbonRead More …

Manganese phosphate coating has the highest hardness and superior corrosion and wear resistances of general phosphate coatings. Manganese phosphating is extensively employed to improve the sliding properties of engine, gear, and power transmission systems. The use of manganese phosphated coatings for improved corrosion resistance can be found in virtually all branches of the metal working-industry. Typical examples mentioned here include motor vehicle components in brake and clutch assemblies, engine components, leaf or coil springs, drill bits, screws, nuts and bolts,Read More …

Aluminium and aluminium alloys are treated by a corrosion resistant conversion coating that is called “chromate coating” or “chromating”. General method is to clean the aluminium surface and then apply an acidic chromium composition on that clean surface. Chromium conversion coatings are highly corrosion resistant and provide excellent retention of subsequent coatings. Different type of subsequent coatings can be applied to the chromate conversion coating to produce an acceptable surface. What we call as phosphating to steel an iron isRead More …

Generally zinc phosphate conversion coating is used to provide long lasting corrosion protection. Almost all automotive industries use this type of conversion coating. It is suitable for the products come against hard weather conditions. Coating quality is better than iron phosphate coating. It forms 2 – 5 gr/m² coating on the metal surface when used as under paint. Application, set up and control of this process are more difficult than other methods and can be applied by immersion or spray.Read More …

Phosphate coatings are used to increase corrosion resistance and improve powder paint adhesion,and are used on steel parts for corrosion resistance, lubricity, or as a foundation for subsequent coatings or painting.It serves as a conversion coating in which a dilute solution of phosphoric acid and phosphate salts is applied via spraying or immersion and chemically reacts with the surface of the part being coated to form a layer of insoluble, crystalline phosphates.Phosphate conversion coatings can also be used on aluminium,Read More …

In selecting a specific media it is helpful to understand some of the materials used and how they compare. Blast media can be made of natural material such as silica, sand, mineral sand, flint, garnet, zircon, and other mineral products. It can be made of some natural byproducts such as walnut shell or corncob. And it can be manufactured of a variety of metal and non-metal compositions such as steel, iron, aluminum oxide, silicon carbide, plastic, wheat starch, and glassRead More …

Abrasive blasting is most often used for preparation of metal surfaces of heavy structural parts, particularly HRS weldments. It is a very good way of removing the encrustations and carbonized oils that are characteristic of this type of product. Blasting operations can be manual or automated and they can be installed as part of a conveyorized powder coating system or as a batch process.The blasting device may be a nozzle type or a centrifugal wheel type. As previously stated, nozzleRead More …