Page 34 - february

PROFESSIONAL ADVICE
Let us consider typical examples of using the developed devices for processing various
types of internal working surfaces. To apply chrome plating on the inner surface of the cylinder
liner made of titanium alloy with a diameter of 30 mm and a length of 250 mm, cylindrical
magnetron devices of the direct and inverted type were developed. The structural diagram of
an integrated technological plasma device, including TsMRS-1 and InvMRS-2, is shown in Fig. 1.
The design of the integrated device is described in detail in [1]. A tubular composite cathode is
used in the design of the TsMRS. The cathode was made from a thin-walled non-ferromagnetic
tube - 3 with a diameter of 0 ‘’ 314 mm with a galvanic coating of the outer surface with "milky"
chromium with a thickness of 100-150 μm. To organize the preliminary ionic treatment of the
inner surface, an inverted magnetron was used. Magnetic system InvMRS - 4 encompassed the
outer surface of part - 5, which made reciprocating movements relative to the discharge area
InvMRS - 6. The treated surface of the part served as the cathode of the InvMRS discharge.
The anode of the magnetron discharge was a short pin 7, located on the axis of the CMRS. The
discharge areas of the TsMRS and InvMRS were separated to exclude the interaction of their
magnetic systems. The working gas was fed directly into the cavity of the workpiece.
In the ion cleaning mode, the source
of the magnetron discharge was connected
to the inverse magnetron circuit. At a
discharge voltage of up to 700 V and an
argon pressure of 1 - 2 Pa, the discharge
current reached 500 mA. This corresponded
to an ion current density on the substrate
of 10–15 mA / cm2. This mode provided
effective preliminary surface preparation
in a time of ≈ 5 min. Coating was carried
out by switching the discharge source
into the TsMRS circuit. During coating,
the workpiece did not move relative to
the CMD. The magnetic system TsMRS -
8 performed a reciprocating movement
in the cathode cavity, the magnetron
discharge - 9 scanned the surface of the
tubular cathode. The outer (chrome) surface of the tubular cathode was sprayed. The sprayed
material was almost entirely used to form the coating. The design of the TsMRS mobile magnetic
system provided one or several discharge arches on the cathode surface. With a double-arch
magnetic system, an argon pressure of 1 Pa and a discharge voltage of 660 V, the discharge
current was 2 A. The density of the ion current in the TsMRS discharge reached 0.2 A / cm2.
The mass rate of condensation of the chromium coating was equal to the value of ion erosion of
the surface material of the TsMRS cathode. The relative value of erosion was 0.65 mg / C, which
corresponds to the tabular value of the ion sputtering rate of chromium, equal to 1.2 at./ion. A
40-μm-thick coating was formed on the substrate in 150 min.

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