Installation Avinit for application of functional nanocoatings

Methods and equipment

Deposition of new functional nanolayer Avinit composite coatings on machine parts and cutting tools is implemented on high-performance Avinit equipment with the use of nanotechnology developed at Research and Development Center "Nanotechnology", which allows to realize the complex methods of coating deposition (plasma chemical CVD, vacuum-magnetron), ion saturation processes and ion processing), combined in one technological cycle.

Block diagram Avinit unit

Recording and control of basic technological parameters of such coatings deposition processes is carried out using special automated system. This makes it possible to choose the most optimal techniques and methods of surface treatment and deposition or their combinations to achieve the maximum technical and economic effect in solving specific tasks.

Automated data acquisition and process control system for coating processes

The control system designed and manufactured allows significant scalability and a fairly inexpensive and significant increase in both speed and accuracy and the number of measurement/control channels.

The Avinit plants currently use a data acquisition and control system in the following configuration

-6 - microprocessor control units at all functional units of the plant, each providing 8 channels of 10-bit ADC and up to 40 channels of digital (relay) control, 2 PWM channels, as well as comparator inputs, counter inputs and real time clock for synchronization of processes (power sources, pumping system, gas filling system, control system). Microprocessor units can control both by the control program written in them and by executing commands in step-by-step mode from the computer (semi-automatic control for technological processes).
- 2 - 8-channel 12-bit ADC up to 100 000 samples per second (acquisition and processing of basic process parameters)
- 1-1 channel 16 bit ADC up to 1 000 000 samples per second (calibration and processing of time critical processes)
- 1-8 channel block for direct control of the most critical parameters directly from the computer.

The operator can view the data, both in real time and from the archive, as well as manage the available features of the installation (eg: the accuracy of control of the substrate potential of about 5V in the range of 0-2000V arc current of 1A in the range of 30-200A). Similar are the possibilities from the central points and other predefined functions that can be built from a set of controlled parameters.

Limitation of parameters available to the operator is based on the OS Linux resource access control system.

Protocol of the automated system of registration of the main technological parameters

Features of Avinit equipment and nanocoatings

Significant increase in the range of sources provided by the complexity of the methods used allows to obtain coatings practically from any elements and alloys, refractory oxides, carbides, nitrides, metal-ceramic compositions based on refractory metals and oxides, which significantly expands the possibilities of creating fundamentally new materials and components for different purposes, working under extreme conditions in terms of temperature, exposure to aggressive environments, mechanical loads.

Avinit coatings are deposited on precision surfaces of high purity class (up to V=12-13) without reducing the surface purity class. This is achieved by using effective methods of surface cleaning in technologies under development - in Ar glow discharge, in high density plasma discharge and with metal ions at voltages above zero growth point as well as prevention of surface damage by micro-arc by means of an effective three-level system provided in Avinit installation.

The coatings are deposited at low temperatures that do not exceed the tempering temperatures of the base material, ensuring that the mechanical characteristics of the coated products are maintained.

Correct selection of individual layer materials, deposition methods and optimization of technological parameters create prerequisites for synthesis of materials with a complex of unique properties, including exceptionally high hardness, strength, chemical stability, low friction coefficient and increased wear resistance.

Developed software products allow to pass to microconstruction of functional coatings and provide obtaining of given nano- and micro-layered multicomponent coatings and reach a qualitatively new level of further modification and improvement of Avinit type coating designs, technology stability and improving quality control when applying such coatings.

Fundamentally new processes (PVD and hybrid PVD+CVD) of controlled formation of multicomponent nano- and micro-layer coatings in metal-nitrogen and metal-carbon systems using vacuum plasma (PVD) and plasma-chemical (CVD) processes have been developed.

For implementation of controlled formation of multicomponent nano- and microstructure coatings technologies were developed using complex vacuum-plasma and plasma chemical processes activated by non-equilibrium low temperature plasma in combination with ion-plasma surface modification.

Technologies and equipment for applying Avinit multilayer strengthening nanocoatings have been developed to improve the functional characteristics of parts for power and general engineering.

Features

Coatings are applied using nanotechnology.
-The thickness of coating is 3-5 microns.
Maintaining surface finish class Ra = 0.025 - 0.036 µm.
Excellent adhesion to the substrate.

Application Antifriction wear-resistant coatings to improve tribological characteristics of friction pairs

Features of nanocoatings:

Nanostructures of coatings.
The coatings have nanolayer structure and consist of layers based on titanium, molybdenum and their compounds with nitrogen in different combinations with thickness ~10-15 nm.
Microhardness 10000-15000 MPa (depending on coating composition).
Coating application maintains surface finish class (initial roughness corresponds to 12-13 finish class).
Low-temperature processes provide coatings with good adhesion to the substrate at temperatures not exceeding 200ºC, which does not lead to a decrease in the rigidity of the substrate.

Spherical plunger surface with Ti-based nanolayer coating

Plunger with Mo-based micro-layer coating

Spools of hydraulic units with Avinit C/P 320 coating

Methods

Combined Hi-Tech Methods

CVD and PECVD methods

The method of vacuum-arc deposition of coatings

Magnetron Coating Method

Combined Hi-Tech Methods

CVD and PECVD methods CVD і PECVD)

CVD coating deposition occurs due to heterogeneous decomposition processes (hydrogen reduction) of metal-containing chemical compounds being in gaseous state in the reaction volume on the heated surface of articles.

Due to high mobility and intensity of mass transfer processes typical of gaseous media the CVD coating method has an exceptional "covering" ability. The ability to provide high mass fluxes of the metal-containing compound in the gaseous state to the coated surface allows high productivity coating processes, in which the growth rate can reach from several hundred microns per hour to several millimeters per hour.

High surface mobility of adsorbed metal-containing compounds makes it possible in CVD processes to obtain coatings with a density close to the theoretical one at temperatures of ~0.15-0.3 of the material melting point, which is not available in other coating deposition methods, and to form perfect epitaxial coatings.

Relative ease of purification from most impurity elements at the stage of obtaining metal-containing compounds due to the selectivity of chemical interaction processes of initial products on heated surface, additional distillation in the process of its transfer to gaseous state from solid or liquid state, in which these compounds are usually in normal conditions, cause a high degree of purity of the coatings obtained by CVD method.

A powerful tool to influence both the kinetics of CVD coating processes and the properties of coatings is plasma-enhanced support (PECVD). Application of various methods of plasma excitation in the reaction volume and control of its parameters allows intensification of coating growth processes, shifting them to the area of lower temperatures, makes processes of formation of a given microrelief and coating structure, impurity composition and other coating characteristics more controllable.

Advantages of the methods:

Unique structure and properties of ion-condensed materials (amorphous, nanocrystalline, microlayer structures, ultra-high rigidity, high purity, exceptionally high adhesion strength to different substrates, special physical-chemical, electrophysical and other properties).
Ecological purity and wide range of coatings (almost all elements) including W, Re, Ta, Nb, Cr, V, Ti, Al, B, their alloys, refractory oxides, carbides, nitrides, and metal-ceramic compositions based on refractory metals and oxides.
Possibility to vary coating rate in a wide range from a few to several thousands of micrometers per hour, which allows to obtain in a controlled manner both thin films with the given structure and composition and to form products with wall thickness up to 10 mm and more from different materials, including hard-to-machine (e.g., W) and unique alloys from immiscible components (e.g., Mo-Cu) (ion-plasma metallurgy).
Highest "hiding power" among all known methods providing formation of thickness homogeneous coatings on the surfaces of complex geometry including blind holes, inner cavities and tubes from L/d >> 1 (L-length of the tube, d-diameter).

Among known high quality coating methods CVD and PECVD methods are beyond competition in most cases where it is necessary:

To apply uniform in thickness high-density coatings on products of complex shape with a developed surface, including internal surfaces, extended and blind cavities, holes, pipes with the ratio L/d>1.
To obtain coatings from refractory, heavy metals, alloys and compounds with density close to theoretical and high purity, to form their self-supporting products of different geometries.
To coat powders and other loose materials, impregnate (compact) porous structures.

Application of uniform coatings on long products

Use of gas-phase and plasma-chemical methods in combination with other methods of coating deposition and surface modification (ion alloying methods, implantation, vacuum-plasma, diffusion, vacuum-thermal methods, etc.) expands even more the possibilities of creating fundamentally new materials and coatings.

The most effective application of CVD and PECVD methods for: є застосування CVD та PECVD методів для:

Application of heat-resistant and heat-resistant coatings of refractory metals, alloys, compounds on units and parts of machines, devices, working in conditions of high thermal loads.
Applying coatings for corrosion protection in aggressive and particularly aggressive liquid and gas environments to protect against high-temperature and atmospheric corrosion.
Manufacturing of crucibles and production equipment for the production of especially pure semiconductor materials, optical and optoelectronic devices.
Manufacturing of semiconductor materials and epitaxial coatings.
Production of conductive, barrier and other functional coatings in radioelectronic and microelectronic industries.
Metallization of bulk materials (diamonds, powders), impregnation of graphite, fibrous materials.
Applying coatings for corrosion protection in aggressive and particularly aggressive liquid and gas environments to protect against high-temperature and atmospheric corrosion.

The method of vacuum-arc deposition of coatings

In the vacuum-arc method, the source of the sprayed material is the cathode of the discharge gap, in which an arc discharge is excited at reduced pressure (in a vacuum). In contrast to the arc discharge under normal (atmospheric) pressure, the vacuum arc discharge occurs in metal vapors, and the discharge is localized in small areas that are micron-sized and move chaotically across the surface of the cathode. Energy density in such areas, called cathode spots, reaches values of 109 W/cm2. Due to this, during a time of ~5-40 nsec. (time of cathode spot rest during its chaotic motion) pressure of metal vapor reaches values of ~105 Pa, and the degree of ionization of metal vapor can be close to 100 %. Ion energy in arc discharge plasma has values of 5-20 eV.

These features of vacuum-arc discharge mainly determine the possibilities of the method to obtain coatings with high degree of adhesion, density, different structural state and phase composition.

Vacuum-arc method allows::

- Generating coatings from almost any metals, alloys and leading compounds;
- Deposition processes in reactive gaseous media (N2, O2, CH4 etc.) allows to obtain coating from oxides, nitrides, metal carbides, oxycarbonitrides and more complex compounds;
- Applying a negative potential to the product, conduct preliminary ion-plasma cleaning of the surface, heat the product and maintain its temperature at the required level, modify the growing structure of the coating and change its other characteristics
The most effective applications for: для:
- -Application of thin-film strengthening, wear and erosion-resistant coatings on cutting tools, molds, machine and machine parts, etc.
- -Applying protective and protective-decorative coatings in the chemical, mechanical engineering, automotive industry, production of medical tools, consumer goods, etc.
- -Application of coatings for protection against corrosion in aggressive and particularly aggressive liquid and gas environments.
- -Looking for coatings and materials for optical and optoelectronic devices.

Magnetron deposition method

The action of the magnetron source is based on atomization of the target-cathode material when it is bombarded by ions of the working gas formed in the plasma of the anomalous glow discharge excited in the crossed electric and magnetic fields. The magnetron sputtering system (MRS) is one of the varieties of diode sputtering schemes.

The main operating characteristics of an MRS are the discharge voltage and current, the specific power at the cathode, the working gas pressure, and the magnetic induction. Argon is usually used as working gas for MPS. The pressure of working gas is within the range of 10-2 -1.0 Pa, the discharge voltage - 300-800 Volt, the magnetic induction near the cathode surface is 0.03-0.1 Tesla. Under these conditions, the current density on the target is only a few thousand amperes per m2, and the surface energy density is ~ 106 W/m2.

DC magnetron sputtering systems can only work with targets of leading materials. If high-frequency power sources are used, it is also possible to spray targets made of non-conductive materials (HF magnetrons).

The magnetron method allows: метод дозволяє:

To produce coatings of almost any metals, alloys, semiconductors, and dielectrics without disturbing the stoichiometry or the original ratio of the components of the sprayed target;
Using mixtures of working and reactive gases (N2, O2, CH4, CO, SO2, etc.) and atomized targets of metals or alloys, obtain coatings of oxides, nitrides, carbides, metal sulfides, etc. compounds, including those which cannot be obtained by conventional thermal evaporation methods;
Treatment of coated surfaces in glow discharge plasma for the purpose of their ionic cleaning and activation prior to coating deposition.
Application of thin-film leading, insulating and other coatings in the electronic, radio, instrumentation and other industries;
Application of educational, reflective, protective and other coatings on the parts of optical systems and devices;
-Applying reinforcing, protective and protective-decorative coatings on metals, dielectric materials, glass, plastics in the manufacture of products for various purposes.