IMPROVEMENT OF PLASMA COATINGS QUALITY CHARACTERISTICS

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IMPROVEMENT OF PLASMA COATINGS QUALITY
CHARACTERISTICS

• Developed by Ievgeniia Tarasova
• Mechanical supervisor -Fedor Vachkevich
• English supervisor -Viktoria Kuzmenko

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The main idea of the present work is to develop
plasma coating formulations and their application
technology that will allow to achieve maximal
performance characteristics.
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Applications areas

• Plasma spray coating is becoming more widely
  used in industry to protect a variety of parts
  and tools from wear, corrosion and erosion

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Plasma coating is the one obtained by applying
molten metal particles on a previously prepared
surface using a plasma jet.

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Improvement of plasma coating quality
characteristics is held in the following areas

• activities to improve the quality by
  pretreatment of powders and protected surface
• activities for coatings quality improvement
  during the process of spraying (technological
  regimes optimization)
• activities for coatings quality improvement by
  treating surfaces after their formation

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Technological parameters that influence
coatings formation and micro-asperities hight
are

• spraying distance
• spraying angle of a pneumatic gun
• abrasive particle size
• air pressure
• powder consumption
• speed of burner

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Influence of dispersion distance (L) and slope
angle of pneumogun (a) on the micro unevenness
height(R?)
Table1
R?10-4? R?10-4? R?10-4? R?10-4? R?10-4?
L ?? a30? a45? a60? a90? Note
50 54-56 57-59 63-66 71-74 Got at permanent air pressure, diameter of nozzle of 510-3m and the abrasive size 0,510-3m
75 56-58 63-65 72-74 86-89 Got at permanent air pressure, diameter of nozzle of 510-3m and the abrasive size 0,510-3m
100 58-60 65-68 75-77 93-96 Got at permanent air pressure, diameter of nozzle of 510-3m and the abrasive size 0,510-3m
125 56-58 62-64 71-73 86-90 Got at permanent air pressure, diameter of nozzle of 510-3m and the abrasive size 0,510-3m
150 54-56 56-58 64-66 77-99 Got at permanent air pressure, diameter of nozzle of 510-3m and the abrasive size 0,510-3m



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Influence of abrasive size (µ) and air pressure
(?) on the micro unevenness height (R?)
Table2
R?10-4? R?10-4? R?10-4? R?10-4?
µ10-3? ?0,2??? ?0,4??? ?0,6??? Note
0,1 43-45 50-52 56-57 Information is got at the distance L0,10m, nozzle diameter of 510-3m, the slope angle a90o
0,2 52-54 60-63 69-71 Information is got at the distance L0,10m, nozzle diameter of 510-3m, the slope angle a90o
0,3 60-62 71-73 81-84 Information is got at the distance L0,10m, nozzle diameter of 510-3m, the slope angle a90o
0,4 63-71 81-83 94-96 Information is got at the distance L0,10m, nozzle diameter of 510-3m, the slope angle a90o
0,5 76-79 93-96 106-109 Information is got at the distance L0,10m, nozzle diameter of 510-3m, the slope angle a90o
0,6 84-87 101-104 118-120 Information is got at the distance L0,10m, nozzle diameter of 510-3m, the slope angle a90o
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The table data (tabl.1 and tabl. 2) analysis
showed that

• with reduction of slope angle of pneumogun to the
  surface of detail the surface roughness also
  reduses at permanent distance from pneumogun to
  the detail and identical compressed air pressure
• the increase of abrasive particles size results
  in the increase of roughness at permanent
  compressed air pressure
• reduction of compressed air pressure results in
  the reduction of roughness at the identical
  abrasive particles size.

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Mathematical method of prediction experiment

• Fig.1 Influence of technological parameters of
  the plasma setting work on eventual properties of
  coverages.
• ?1 current strength(?)
• ?2 tension on an arc (?)
• ?3 expense of plasma-forming gas of
  argon (l/mine)
• ???D? is the compromise region of the
  criteria ?1, ?2, ?3, ?4
• FGDE is optimal spraying region of thermal
  coverages.

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In order to improve the coatings quality it is
recommended to apply plasma and micro-plasma
melting

?)
b) c)
Fig.2 Structure of sprayed coverage from the
SNGN alloy after melting a in a stove with a
low oxidizing atmosphere b currents of
high-frequency c micro-plasma burner. ? 200

?)

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Conclusion

• 1. The analysis of surface preparation approach
  used before spraying gave an opportunity to
  choose pnuematical surface preparation by means
  of electrolytic as the most efficient one since
  it allows to adjust the surface roughness in a
  wider range.
• 2. Mathematical investigation made it possible
  to create the range of criteria compromising by
  means of graphical-analytical approach. Moreover
  it allowed to make optimal range of gas-termal
  spraying.
• 3. Among all the investigated methods of surface
  melting aimed on quality improvement it is
  advisable to implement plasma and microplasma
  melting as it makes possible to achieve tight and
  strong coupling of protection layers of steel and
  titan.
• All the investigations held in the research work
  allowed to develop technical tutorials used for
  producing improved quality features plasma
  surfaces.

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• THANKS FOR ATTENTION

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