Physical vapour deposition (PVD) describes a variety of vacuum deposition methods used to deposit thin films by the condensation of a vaporized form of the desired film material onto various work piece surfaces.
Physical vapour deposition (PVD) coating is one of good method of thermal coating. Physical vapour deposition (PVD) surface coatings make it possible to increase the surface hardness of treated components. Despite the good wear resistance of such coatings, the fatigue behaviour of the bulk material may be affected by changes in the residual stress field and micro hardness.There are three steps of formation of any deposition transition from condensed phase (liquid or vapour) to vapour phase, transport of vapour from source to substrate andcondensation of vapour followed by film nucleation and growth.
There are different types of PVD coating technology 1) Cathodic arc deposition, 2) Electron beam physical vapour deposition, 3) Pulsed laser deposition, 4) Sputter deposition.
Cathodic arc deposition: In which a high-power electric arc discharged at the target (source) material blasts away some into highly ionized vapour to be deposited onto the workpiece.
Electron beam physical vapour deposition: In which the material to be deposited is heated to a high vapour pressure by electron bombardment in “high” vacuum and is transported by diffusion to be deposited by ucondensation on the (cooler) workpiece.
Pulsed laser deposition: In which a high-power laser ablates material from the target into a vapour.
Sputter deposition: In which a glow plasma discharge (usually localized around the “target” by a magnet) bombards the material sputtering some away as a vapour for subsequent deposition
PVD Coatings are made for a specific set of properties high wear resistance, high oxidation resistance, low friction, high hardness at high working temperature, adhesion, scratch resistance and better surface finish in precise colour.
Plasma-enhanced chemical vapour deposition is a process used to deposit thin films from a gas state (vapour) to a solid state on a substrate. Chemical reactions are involved in the process, which occur after creation of plasma of the reacting gases. The plasma is generally created by radio frequency (AC) or DC discharge between two electrodes, the space between which is filled with the reacting gases.
HIPIMS stands for High Power Impulse Magnetron Sputtering. This relatively recent advance in pulsed sputtering uses very high power, short duration pulses of power to both generate a plasma and ionize a large percentage of the sputtered atoms. These ionized atoms have much higher energies than sputtered atoms in conventional magnetron sputtering and have been found to yield very dense and stable films. Currently, this technique has been used principally for wear resistant coatings (tribological) and recent work has extended this technique to the field of optical coatings.
The Plasma Spray Process is basically the spraying of molten or heat softened material onto a surface to provide a coating. Material in the form of powder is injected into a very high temperature plasma flame, where it is rapidly heated and accelerated to a high velocity. The hot material impacts on the substrate surface and rapidly cools forming a coating. This plasma spray process carried out correctly is called a “cold process” (relative to the substrate material being coated) as the substrate temperature can be kept low during processing avoiding damage, metallurgical changes and distortion to the substrate material.
High Velocity Oxygen Fuel (HVOF)
High Velocity Oxygen Fuel (HVOF) coating is a thermal spray coating process used to improve a component’s surface properties or dimensions, thus extending equipment life by significantly increasing erosion and wear resistance and corrosion protection.
Molten or semi-molten materials are sprayed onto the surface by means of the high temperature, high velocity gas stream, producing a dense spray coating which can be ground to a very high surface finish.
The utilization of the HVOF coating technique allows the application of coating materials such as metals, alloys and ceramics to produce a coating of exceptional hardness, outstanding adhesion to the substrate material, and providing substantial wear resistance and corrosion protection.
Salt Bath Nitride
Salt Bath Nitriding was originally created as an alternative to gas nitriding that would produce a more uniform case through surface contact between the substrate and liquid salt. When steel parts are placed into a preheated liquid salt, there is sufficient energy localized near the surface due to differences in chemical potential that then allows nitrogen and carbon species to diffuse from the salt into the steel substrate. The process is carried out at 400-550°C, making it faster than gas nitriding. Lower temperature cycles produce an S-Phase/Expanded Austenite case in stainless steels. Post-oxidation after nitriding combined with polishing produces coatings with exceptional appearance (black color) and high corrosion resistance (greater than electrolytic chrome plating). Salt Bath Nitriding is particularly common application tool & die industry as well as the oil & gas industry.
ACT offers a wide variety of Physical Vapour deposition latest coatings both as a mono layer (TiN, CrN, TiAlN, AlTiN, AlCrN, and TiCN) or Multilayered Nano-Composite Gradiant coatings (Naco, AlCrNSi3N4, Nacvic and Natvic) Nacvic consist of Nacro plus DLC as top coating.