Vacuum plasma spray/low pressure plasma spray (VPS/LPPS)

Just like atmospheric plasma spraying, vacuum plasma spraying (VPS) or low-pressure plasma spraying (LPPS) is a thermal spraying technology. It is carried out inside a vacuum chamber or in an inert gas, such as argon, maintained at low pressure to avoid oxidation. Metal or ceramic powders are injected into a hot gas plasma, which melts the powders. The molten droplets are projected onto a substrate to form the coating.

The advantage with VPS/LPPS is that the spraying speed and temperature of molten particles can be higher than in air, resulting in coatings with reduced oxide inclusions, higher bonding strength and density than what can be achieved by APS. VPS/LPPS coatings have low porosity and high purity.