Thermal Spray Systems APS VPS

Electron can now offer & supply specialist VPS/APS & HVOF units under its own brand name and as being 100% focused upon the gas turbine industry. All of our supplied equipment is sourced from our Swiss manufacturing & technology partner and thus ensuring the highest levels of quality and performance being available from our units here.
Electron’s systems for supply into the gas turbine sector are offered with Swiss technology & designs and as being leveraged upon Swiss manufacturing expertise with a long history of equipment supply into highly regulated industrial sectors. This enables Electron to offer its customers the supply of premium quality coating deposition systems and which is the perfect technical counterpart equipment for follow on deposition coating processes such as after the applications of bond coatings (Plain Aluminide & Platinum Aluminide) and as which may have also been potetially applied by Electron’s CVD Aluminide coating furnaces.

Vacuum Plasma Spray (VPS), Atmospheric Plasma Spray (APS) & HVOF spray systems are amongst some of the most versatile and flexible thermal spray processes available due to their ability to spray a wide range of materials such as most metals, ceramics and alloys onto many different substrate materials such as metals, ceramics and composite materials. Also, a broad range of powder particle sizes can be used as well as multi powder flow options for consecutive spraying of different powders onto the same part. Benefits of VPS/APS/HVOF include resistance against heat through temperature management (TBC’s), oxidation & corrosion protection, superior wear & abrasion properties & clearance control for abrasives and abradables.  Thus, deposition systems can be used for a very wide range of applications across gas turbine engines and are equally applicable to both the aerospace & industrial gas turbine industries.

Features

Main applications

What is plasma spray?

The plasma spraying process involves the latent heat of ionized inert gas (Plasma) being used to create the heat source. One of the most common gases used to create plasma is Argon and with Hydrogen & Helium also being applicable. This is referred to as the primary gas.

Argon flows between the electrode and nozzle. A DC high voltage electric arc is struck between the nozzle and the electrode, which ionizes the gas stream. By increasing the arc current, the arc can increase the degree of ionization. This has the effect of increasing the power and also, due to the expansion of gas, an increase in the velocity of gas stream.

When a plasma is created by Argon only it requires a very large arc current (Typically 800 to 1,000 amps) to create sufficient power to melt most materials. With this level of arc current the velocity may be too high to allow materials with a high melting point to be made molten. Therefore, to increase the power to a level sufficiently enough to melt ceramic materials it is necessary to change the thermal and electrical properties of the gas stream. This is generally done by adding a secondary gas to the plasma gas stream (most usually Hydrogen and with Helium as another possibility).

Once the appropriate gas stream has been established for the material being sprayed, the feed stock (material in various powder forms) is injected into the gas stream

Atmospheric Plasma Spraying (APS)
Atmospheric Plasma Spraying (APS) is a versatile thermal spray process for the highest quality, reliability and durability.
The process produces enough energy to melt the majority of available materials and thus offers a very high flexibility. Plasma spray coatings can be highly controlled and their properties customized in regard to parameters such as thickness, porosity, roughness and hardness.

Vacuum Plasma Spraying (VPS)
Vacuum Plasma Spraying (VPS) is a versatile thermal spray process for the highest quality, reliability and durability with the added exclusion of oxygen in low-pressure inert gas atmosphere processing. VPS coatings can offer very pure and dense deposition coatings and with a superior level of diffusion bonding present for metallic coatings when applied (after preheating) in the 850 -950°C range. Vacuum Plasma spray coatings can be highly controlled and their properties customized in regard to parameters such as thickness, porosity, roughness and hardness. The vacuum chamber is evacuated by a combined mechanical pumping system before the process starts and with the vacuum chamber pressure being capable of being evacuated to a level of less than 1 mbar abs. This ensures that any residual oxygen or water vapor adhering to the chamber is fully evacuated and will not detrimentally influence the high-purity gas atmosphere. Oxide free coatings are applied under inert gas atmospheres at typical processing pressure levels of  between 20 -300mbar.
The VPS process also offers the highly effective RTA (reverse transfer arc) cleaning process which effectively etches and cleans the substate surface and offers a chemically clean surface for the deposition of these coatings at elevated temperatures.

High Velocity Oxygen Fuel Spraying (HVOF)
High Velocity Oxygen Fuel (HVOF) is a thermal combustion coating process and answers to the requirement for cost effective coatings which can be harder, more wear-resistant and corrosion-resistant surfaces. We offer systems which may be operated with gas and liquid fuels. HVOF utilizes confined combustion and an extended nozzle to heat and accelerate the powdered coating material. Typical HVOF devices operate at hypersonic gas velocities. The extreme velocities provide kinetic energy which help produce coatings that are dense and very well adhered.

More information?

Please contact us if you are interested to learn more about any features of our thermal spray systems and processes and we would be pleased to discuss and explain our many value adding technologies within this specialist area.