Thermal Spray – Here’s A Second Look

Sure, hard facing pertains to thermal spray, though it is more about depositing’filler’ materials onto a metal surface for repair or dimensional restoration. And, normally, these improvements relate solely to promoting wear resistance, alone.

But did you know these’overlays’of material might also subscribe to corrosion prevention, low friction, anti-fretting or galling, even release (nonstick) properties? The thing that was formerly developed for rebuilding worn parts or individuals with machining errors is now extending into many fields of surface engineering.

The principle of applying thermal spray is quite basic. That’s, molten or semi-molten metals, alloys, or ceramics, atomized, are fed toward the workpiece by a jet stream of air.

As these particles impinge the work surface, they dissipate their heat, quickly cooling, accumulating, fusing into a cast-like structure described as highly cohesive. Resultant surface finishes, as-sprayed, typically range between 100 and 400 micro inches. So, based on requirements, finish grinding or polishing might be required. (Values under 10 micro inch are greatly attainable.)

What kinds of materials can be applied by thermal spray? The clear answer is most metals, ceramic, cermet(ceramic-metal combinations), tungsten carbide, even organic-based compounds like polyesters.

Adhesion, largely mechanical (versus metallurgical), is excellent. Grit blast, as a method of surface preparation, is typical to best promote adhesion. Though tensile strength can be sometimes superior with higher temperature processes, based on the choice of material, through micro-welding or diffusion.

Common methods of application include HVOF (high-velocity oxygen flame), which is comparable to the combustion powder thermal spray process (LVOF), though with increased density, stronger bonds, and lower residual tensile stress. Plasma spray and vacuum arc spray are also popular.

Applications continue to cultivate with this particular technology. Food processing, packaging, molding, plastics, paper and chemical processing, are simply some of the newer, relevant applications. (Many materials are regarded non-objectionable with FDA.)

Ideally, search for thermal spraying processes with minimal heat transfer to your workpiece. spray in bedliner Just to be sure your surfaces are free of warping, surface distortion. Latest versions include’higher kinetic energy systems’to ensure highest density, particle-to-particle cohesive bonding. The result is long-lasting, cost-effective, surface performance.

The Teflon and Powder Coating Processes

The target of both Teflon coating and powder coating is actually similar, although the processes used to apply each of them are slightly different. Both coatings are designed to impart some specific property to them that’s being coated. For powder coating, the goal is really a protective layer that’ll keep them from being damaged, although with Teflon, usually, a non-stick surface may be the property that’s designed to be given to them it will be applied to.

The Powder Coating Process

The powder coating that gets applied is simply that-a powder. It basically gets sprayed onto the surface and then dries to form a coating. Here’s how the powder coating process works:

1. The powder is placed in the feeder unit for the spray gun. Compressed air inside the system then diffuses it so that it becomes like a fluid though it continues to be technically a powder.

2. The gun siphons out the powder by pushing high-velocity air and propelling the powder from the feeder to the gun.

3. Most guns can spray powder anywhere from 10 to 25 feet. Once the powder leaves the gun, it seems like a cloud that’s moving toward them that’s being coded.

4. An electrode on the end of the spray gun emits a charge that’s passed on to the particles of powder if they pass through the tip. That charge causes the powder particles to start searching for something to latch onto and form a protective coating over it.

And so the powder coating process is quite simple. After it has been applied, it is baked onto the item. The entire process is very simple to a typical painting job, except powder coating includes a great many benefits over ordinary paint. For example, any powder that doesn’t put on them can be recycled, and the coating it provides is much thicker than paint. So powder coating is a way to provide a smooth, protective coating to something, so how about Teflon coating?

Leave a reply

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>