powder coating pretreatment

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Phosphate coatings-the recognised pre-treatment for steel substrates

The recognised pre-treatment for steel substrates just prior to application of powder is phosphating which can vary in coating weight. The greater the conversion coating weight the greater the degree of corrosion resistance achieved; the lower the coating weight the better the mechanical properties. It is therefore necessary to select a compromise between mechanical properties and corrosion resistance.  High phosphate coating weights can give trouble with powder coatings in that crystal fracture can occur when the coating is subjected toRead More …

Considerations for Choosing a Coolant for metal working process

Different metal working processes have varying cooling and lubrication needs. Coolants have many properties that increase their efficiency, extend their life, and minimize the potential to damage tools and products. Therefore, when choosing a coolant, many factors need to be considered. These considerations include: Tramp oil rejection Ability to settle out solids Bacterial resistance Corrosion and rust resistance Emulsification capability Foaming nature and resistance Optimal coolant life Longevity of coolant as measured against current industrial standards Cost of coolant ChemicalRead More …

Paint Removal

When repainting a part,prior to application of the new paint coat  the old,paint often must be removed. The waste reduction assessment should start by examining what causes the need for repainting: inadequate initial part preparation; defects in coating application; equipment problems; or coating damage due to improper handling. While no process is perfect, reducing the need for repainting has a direct effect on the volume of waste generated from paint removal. Once the need for paint stripping has been reducedRead More …

Definitions for corrosion classification

As an aid in finding what requirements should be made for pre-treatment, we can define different corrosion classification: Corrosion Class 0 Indoors with relative humidity over 60% Very little corrosion risk (aggressivity) CORROSION CLASS 1 Indoors in non-heated, well ventilated room Little corrosion risk (aggressivity) Corrosion Class 2 Indoors with fluctuating temperature and humidity. Outdoors in inland climates, far from sea and industry. Medium corrosion risk (aggressivity) CORROSION CLASS 3 In densely populated areas or near industrial areas. Above open waterRead More …

Filiform corrosion is special kind of corrosion appearing mostly on aluminum

Filiform corrosion is special kind of corrosion appearing mostly on aluminum. The phenomenon resembles a worm creeping under the coating, always starting from a cut edge or a damage in the layer. Filiform corrosion develops easily when the coated object is exposed to salt in combination with temperatures 30/40°C and relative humidity 60-90%. This problem is therefore limited to coastal areas and linked with unfortunate combination of aluminum alloys and pre-treatment. To minimize filiform corrosion it is advised to ensure aRead More …

Phosphate treatment for powder coating

Iron phosphate Treatment with iron phosphate (often called thin layer phosphating) provides very good adhesion properties and has no adverse effects in the mechanical properties of the powder coating. Iron phosphate provides good corrosion protection for exposure in the low and middle corrosion classes, though it cannot compete with zinc phosphate in this respect. Iron phosphate can be used in either spray or dip facilities. The number of steps in the process may vary from 2-7, depending on the basemetalRead More …

Mechanisms of corrosion protection inferred by Anodic Coatings fall into two classes

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 …

How to prevent corrosion for substrate

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 …

There are a number of different abradable coating types

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 is relatively free of the iron hydrates

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 …