PLASMA TECHNOLOGIES

FOR DEPOSITION OF FUNCTIONAL COATINGS

In 2001, a workcell for plasma deposition was commissioned for service NPK LUTS. The following magnetron-type installations are used for the deposition of films of metals, alloys and dielectrics onto surface of treated products:

• Installation for the deposition of high-conductivity coatings "UNVP" designed in NPK LUTS;
• Unit of continuous operation "Oratorio-5" produced in NPO "Kvarts", Kaliningrad".

"UNVP" INSTALLATION

This installation is intended for the deposition of high-conductivity protecting and other functional coatings onto large-scale products. The necessity for such an installation in NPK LUTS is dictated by production needs as well as by the fact that domestic industry does not produce serial magnetron-type installations for the treatment of products of required dimensions.

"UNVP" is made on the same principle as the axial-symmetric diode magnetron.

Coating is deposited onto a product surface in vacuum at sputtering of target (cathode) material with ions of the plasma produced in the magnetron-type discharge.

Parameters of the magnetron-type discharge:

• pulse mode of operation;
• pulse repetition rate - 150 Hz;
• power per pulse - up to 100 kW;
• duty factor - 3.

Maximum overall dimensions of a product under treatment:

• sheet - 0.2 х 0.6 х 1.6 м;
• pipe - inner diameter ranges from 0.3 m up to 0.7 m, length - 1.6 m.

Material of coating: Сu, Ti, TiN, stainless steel, etc.

Coating thickness ranges from 0.1 up to 30 µm, thickness non-uniformity is no more than 10%.

"ORATORIO 5" INSTALLATION

This installation serves for the deposition of functional coatings onto small-size products. It makes possible the deposition of Al, Co, Cr, Au, Ag, Ti, Ta - films and films of other nonmagnetic materials and their alloys .

The magnetron-type discharge allows the plasmo-chemical synthesis of some compounds such as nitrides, oxides and carbides of some metals.

The vacuum chamber of the installation is equipped with a planetary system for rotating substrates to ensure uniform coating deposition.

Thickness of deposited coatings depends on the time of deposition and is varied from 0.01 µm up to tens of microns.

Discharge power (the d.c. mode) is up to 5 kW.

Deposition rate - 1 µm/min.

Maximum sizes of products under treatment are: diameter - 200 mm, length - 150 mm.

To measure the main parameters and to study properties of produced coatings, an express -laboratory has been organized as a part of the workcell for plasma deposition. For checking plasma composition in the process of deposition a "Spectrographic complex" was purchased.

Advantages of the magnetron method:

• no waste products polluting the environment inherent, in particular, in galvanic method;
• no droplet phase (a drawback of the vacuum-arc method);
• higher adhesion as compared with evaporating method;
• high uniformity of coating along the length of the accelerating structure unattainable with beam methods requiring either complicated beam scanning systems or robotics for the ion source transportation;
• simultaneous deposition of coating onto whole surface of the treated product.

Technologies of vacuum deposition of functional coatings allows:

• applying of less expensive and highly workable materials;
• reducing the consumption of expensive materials, imparting required properties to a treated surface;
• replacing methods of coating deposition adversely affecting the environment.

Products with deposited coatings may be used in production of :

• elements for accelerating structures of linear accelerators and cyclotrons;
• medical-technical apparatus and instruments;
• equipment for gas-and-oil-processing complex;
• products of machine-building and instrument-making industries and microelectronics;
• optical devices.

The following processes have been designed and are phased in NPK LUTS:

• copper plating of steel choke and contact flanges of electron accelerator waveguides (for brazing);
• copper plating of Ta targets of electron accelerators (for diffusive welding);
• deposition of Al or Ti-coating onto lavsan backing to be applied in ionization chambers of electron and medical accelerators;
• deposition of Co-coating onto Al electrodes of linear ion accelerator resonators;
• deposition of In-coating onto electron accelerator RF system components made from stainless steel, brass, carbon steel to ensure vacuum seal and RF-contact.

The introduction of above processes allows one to have an appreciable improvement of quality of the most critical accelerator units and reduction of their production cost. In future, the spectrum of suggested coatings and range of products for which surface treatment we apply plasma technologies will steadily expand.