The Centre for Plasma Technologies – PLASMA D.O.O offers thin film PVD (Physical Vapour Deposition) coatings for functional and decorative applications. The deposition of PVD coatings is an environmental technology, with no contamination of working premises, nor environmental pollution. Our high-performance production or R&D vacuum sputtering and thin film evaporation systems provide coatings on a variety of materials including polymers and composites, glass, ceramics, metals and hybrid substrates. The use and properties of the various coatings available from PVD coatings can, in many cases, be tailored to the individual customer application.
Our PVD system utilizes the cathodic arc and magnetron sputtering principles combined with multiple targets (titanium, aluminium, stainless steel, copper etc.) and has the ability to deposit different coatings during the same coating cycle. This PVD equipment has large coating zone so we can coat large complex shapes or large volumes of small components. The flexibility to coat a variety of substrate materials is extremely advantageous, particularly heat sensitive materials like plastic.
The parts to be coated are first cleaned. The cleaning process varies depending on the level of quality from the electroplater, substrate material and geometry. The parts are loaded into the vacuum chamber on custom fixtures designed to optimize the chamber load size and insure coating uniformity.
The vacuum chamber is evacuated to 2×10-2 Pa to remove any contaminants in the system. The vacuum chamber is backfilled with inert (argon), reactive (oxygen, nitrogen...) gas or gas mixture and ionized, resulting in a glow discharge (plasma). This is the plasma cleaning and activation (for polymers and composite materials) stage and prepares the parts for the initial coating deposition.
A high current, low voltage arc is initiated on the surface of the evaporator’s cathode (target). The metal is evaporated and instantaneously ionized. These metal ions are accelerated at high energies into the vacuum through an inert (argon) and reactive (oxygen, nitrogen, acetylene...) gas or gas mixture (oxygen-nitrogen, nitrogen-acetylene...) and subsequently deposited on the substrate parts. The basic properties of the metal being evaporated (target) remain unchanged during the metal deposition cycle. Changing the volume of gas and type of gas during the reactive deposition cycle changes the nature of the coating producing ceramic films (carbides, nitrides, oxides...) and composite films (oxynitrides, carbonitrides...)
In our Centre the PVD sputtered coatings are produced in an unbalanced-magnetron sputtering process, within the sputtering gas ions out of plasma are accelerated towards the target (titanium, aluminium, stainless steel, copper...) consisting of the material to be deposited. Material is sputtered from the target and afterwards deposited on a substrate in the vicinity. In our magnetron sputtering system are used stronger permanent magnets below the target resulting in the expansion of the plasma away from the surface of the target towards the substrate. The effect of the unbalanced magnetic field is to trap fast moving secondary electrons that escape from the target surface. These electrons undergo ionizing collisions with neutral gas atoms away from the target surface and produce a greater number of ions and further electrons in the region of the substrate considerably increasing the substrate ion bombardment. Effectively secondary plasma is formed in the region of the substrate. When a negative bias is applied to the substrate, ions from this secondary plasma are accelerated to the substrate and bombard it.
Physical Vapour Deposition (PVD) is a process to produce a metal vapour that can be deposited on electrically non-conductive and conductive materials as a thin highly adhered pure metal, ceramic or composite coating. Single or multi-layer coatings can be applied during the same process cycle. Additionally the metal vapour can be reacted with various gases (oxygen, nitrogen, acetylene…) to produce ceramic (Oxides, Nitrides, Carbides...) or composite films (Carbonitrides, Oxynitrides...).
The process is carried out in a vacuum chamber at high vacuum (2×10-2 Pa) using two types of PVD techniques: Cathodic arc evaporation and Magnetron sputtering.
The PVD is a process for both colouring and the improvement of wear resistance. It involves the deposition of often very hard, thin ceramic or composite coatings (hardness > 2000 HV).
* These materials are plated with Ni and Cr prior to PVD coating.
Titanium, particularly titanium nitride (TiN), is one of the best bio-inert, bio-compatible materials. Therefore the application of these coatings is widespread: medical or dental instruments, surgical tools and implants, tea and coffee filters...
The PVD coatings based on Titanium, Stainless Steel, aluminium or titanium nitride can be used as reflective coating on glass mirrors. The TiO2 and Al2O3 can be used as anti-reflective layers for some applications. Also, TiO2 on glass attain the i.e. “self-cleaning” effect – the surface does not attract dust, dirt, water or moisture.