Vacuum-plasma, plasma methods of surface modification of engineering

parts

Victor Kazachenko, PhD, Associate professorLaboratory of Surface Physics and Thin Films,

Belarusian State University of Transport, Gomel 246653, Belarus, kvp_@mail.ru

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Modification of engineering parts

• PART 1Deposition of nanostructured TiN+C coatings from pulsed cathodic-arc plasma discharge in vacuum

• PART 2Electrofriction Discharge Hardening (EDH) of engineering parts operating under the conditions of abrasive wear

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PART 1 Nanostructured TiN+C coatings

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Pulsed cathodic arc carbon plasma source

• The cathode is made of titanium.• The arc ignition system and additional anode are made of graphite.• The pressure of nitrogen is about 6·10-3 Pa during the coating synthesis.

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Structure of TiN+C coating, synthesized by pulsed-arc method

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2 m

SEM image of TiN+C coating

5 m

SEM image of TiN coating

AFM topography AFM phase

AFM 3D

Raman spectroscopy study of TiN+C coatings

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Carbon

Aco

ustic

al m

odes

G m

ode

TiN

D m

ode

Opt

ical

m

odes

Tribotechnical properties of TiN-C coatings

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0 50 100 150 2000,0

0,2

0,4

0,6 Initial contact pressure:TiN

580 MPa 660 MPa

TiN+C 660 MPa 725 MPa

Co

eff

itie

nt

of

fric

tio

n

Cycle

plunger pairs of high-pressure fuel pumps

measuring tools

simmerings

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Applications

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PART 2Electrofriction Discharge Hardening

(EDH)

Electrofriction Discharge Hardening Scheme

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1 - rotating tool, 2 - water, 3 - sample, 4 - zone of discharge

The setups allow hardeningflat surfaces

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Experimental Setup Parameters Value

Maximum discharge power, kW 7,5

Tool rotation frequency, min-1 1 - 200

Linear speed, m/min 0.05 - 10

The size of the processed part, mmmaximum lengthmaximum widthmaximum depth

50022550

Structure and microhardness with thickness of the modified layer of 65Г steel (65Mn)

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EDH current - 250 A

The distance from the surface, mm

HV

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Structure and microhardness with thickness of the modified layer of 35ХГСА steel (35CrMnSi)

EDH current - 200 A

HV

The distance from the surface, mm

Structure of surface layers of ВЧ100 cast iron (ISO 900-2)

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100x 500x

Quasi ledeburiteMicrohardness – up to 1000 HV

Graphitic inclusions are preservedMartensite and residual austeniteMicrohardness – 800-850 HV

Gradual transition to the pristinecast iron structure

Hardened chisel-like plowshares (“Kverneland”)

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Hardened cartridge of cutters for rock

fracturing

The lifetime of the hardened plowshares increased by 76 ha in sandy loam soils

Hardened zone

Hardened zone

Conclusion• In comparison with conventional TiN coatings, the

nanocomposite layers of TiN containing carbon demonstrate lower roughness, less defects, significantly lower coefficient of friction and high wear resistance

• Electrofriction discharge hardening (EDH) method allows hardening layers up to 3.5 mm deep without significant heating of the part. The method does not use expensive welding materials. Hardened layers exhibit the abrasive wear rate up to 5 times lower than the pristine material. The EDH is characterized by high productivity, low-cost equipment and easy automation. The EDH is suitable for hardening the soil processing and rock fracturing tools in agriculture and mining machinery.

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Thank You!

We are looking forward to successful cooperation.

Victor Kazachenko, PhD, Associate professorLaboratory of Surface Physics and Thin Films,

Belarusian State University of Transport, Gomel 246653, Belarus,

kvp_@mail.ru

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