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Protection and Restoration
Benelmekki and Erbe (2019) point out that CVD processes are well known and
developed and reactors used for the process variations depend basically on the type
of precursors, deposition conditions, and forms of energy introduced to the system to activate the desired chemical reaction. Apart from the previously mentioned
modifications, the authors consider two more processes as the most established
ones:
• Metal-organic CVD process which is applied when metal-organics are used
as precursors, such as trimethylaluminum, Al 2 (CH 3 ) 6 , or trimethylgallium,
Ga(CH 3 ) 3
• Aerosol-assisted CVD where liquid precursors are introduced to the CVD
reactor in an aerosol form, facilitating its evaporation (Benelmekki and
Erbe, 2019)
Physical vapor deposition (PVD) is a vacuum process where material is transferred
in the form of vapor particles from a material source to the substrate surface where it
is condensed as a film (Bouzakis and Michailidis, 2018). PVD encompasses a broad
family of vacuum coating processes employing material removal from a source by
evaporation or sputtering. Chemical compounds are deposited either by using a similar source material or by introducing reactive gases (nitrogen, oxygen, or simple
hydrocarbons) containing appropriate surfactants and reacting with metal from the
PVD source. Most PVD processes are typically named after the means used for producing the physical vapor, mainly evaporation and sputtering.
• Evaporation can be resistive, inductive, electron beam, activated reactive
evaporation, or arc evaporation under DC or AC.
• Sputtering can be diode or triode, ion beam, or magnetron sputtering, i.e.,
direct current (DC), radio frequency (RF), pulsed cathode, dual magnetron sputtering, or high-power pulsed magnetron sputtering (HPPMS or
HIPIMS: high-power impulse magnetron sputtering). A promising technology for deposition of thick films is the high-speed physical vapor deposition
(HS-PVD) process based on a hollow cathode glow discharge (Bouzakis
and Michailidis, 2018). Figure 2.9 illustrates the plasma spray-physical
vapor deposition process.
The PVD process is able to produce a metal vapor which is then deposited on electrically conductive materials as a thin, highly adhered pure metal or alloy coating
(Shang and Zeng, 2013). The process is carried out at high vacuum using a cathodic
arc source and the coating is deposited over the entire object surface uniformly
rather than in localized areas. The authors state that all reactive PVD hard coating
processes combine three subsystems:
1. A method for depositing the metal
2. Combination with an active gas, such as nitrogen, oxygen, or methane
3. Plasma bombardment of the substrate to ensure a dense, hard coating
Protection and Restoration
Benelmekki and Erbe (2019) point out that CVD processes are well known and
developed and reactors used for the process variations depend basically on the type
of precursors, deposition conditions, and forms of energy introduced to the system to activate the desired chemical reaction. Apart from the previously mentioned
modifications, the authors consider two more processes as the most established
ones:
• Metal-organic CVD process which is applied when metal-organics are used
as precursors, such as trimethylaluminum, Al 2 (CH 3 ) 6 , or trimethylgallium,
Ga(CH 3 ) 3
• Aerosol-assisted CVD where liquid precursors are introduced to the CVD
reactor in an aerosol form, facilitating its evaporation (Benelmekki and
Erbe, 2019)
Physical vapor deposition (PVD) is a vacuum process where material is transferred
in the form of vapor particles from a material source to the substrate surface where it
is condensed as a film (Bouzakis and Michailidis, 2018). PVD encompasses a broad
family of vacuum coating processes employing material removal from a source by
evaporation or sputtering. Chemical compounds are deposited either by using a similar source material or by introducing reactive gases (nitrogen, oxygen, or simple
hydrocarbons) containing appropriate surfactants and reacting with metal from the
PVD source. Most PVD processes are typically named after the means used for producing the physical vapor, mainly evaporation and sputtering.
• Evaporation can be resistive, inductive, electron beam, activated reactive
evaporation, or arc evaporation under DC or AC.
• Sputtering can be diode or triode, ion beam, or magnetron sputtering, i.e.,
direct current (DC), radio frequency (RF), pulsed cathode, dual magnetron sputtering, or high-power pulsed magnetron sputtering (HPPMS or
HIPIMS: high-power impulse magnetron sputtering). A promising technology for deposition of thick films is the high-speed physical vapor deposition
(HS-PVD) process based on a hollow cathode glow discharge (Bouzakis
and Michailidis, 2018). Figure 2.9 illustrates the plasma spray-physical
vapor deposition process.
The PVD process is able to produce a metal vapor which is then deposited on electrically conductive materials as a thin, highly adhered pure metal or alloy coating
(Shang and Zeng, 2013). The process is carried out at high vacuum using a cathodic
arc source and the coating is deposited over the entire object surface uniformly
rather than in localized areas. The authors state that all reactive PVD hard coating
processes combine three subsystems:
1. A method for depositing the metal
2. Combination with an active gas, such as nitrogen, oxygen, or methane
3. Plasma bombardment of the substrate to ensure a dense, hard coating