What Does Surfacing Mean?
Surfacing refers to altering the surface characteristics of a material to achieve improved chemical or physical properties. This is done by welding or by spraying a filler metal coating onto a substrate. Surfacing imparts corrosion prevention properties to the substrate metal.
Corrosionpedia Explains Surfacing
Surfacing is performed by one of several different industrial techniques, including:
- Weld overlaying
- Thermal spraying
- Chemical vapor deposition (CVD)
These methods permit precision in the resulting thickness of the filler metal deposit. The thickness is extremely important because it can vary from several millimeters to a few microns and influences metallic properties such as hardness. For example, surface hardness can be altered to 1000 HV for nitrided steels and 3500 HV with the deposition of a TiN PVD coating.
Surfacing is used as an industrial technique for corrosion resistance. Typically only one layer is required for this purpose. Rather than accumulating several layers, selecting the appropriate filler metal is the most important criteria for corrosion prevention. The selected metal must be chemically compatible with the substrate in order to act as a sacrificial anode.