brian borawski n.
Skip this Video
Loading SlideShow in 5 Seconds..
Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components PowerPoint Presentation
Download Presentation
Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components

Loading in 2 Seconds...

play fullscreen
1 / 37

Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components - PowerPoint PPT Presentation

  • Uploaded on

Applied Research Laboratory Advanced Coating Division. Brian Borawski. Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components. Dr. Judith Todd Dr. Douglas Wolfe Dr. Jogender Singh Dr. Albert Segall. June 23 rd , 2011. Ceramic (brittle coating). Metallic coating.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components' - ianna

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
brian borawski

Applied Research Laboratory

Advanced Coating Division

Brian Borawski

Multilayer Erosion Resistant Coatings for the Protection of Aerospace Components

Dr. Judith Todd

Dr. Douglas Wolfe

Dr. Jogender Singh

Dr. Albert Segall

June 23rd, 2011

challenge statement

Ceramic (brittle coating)

Metallic coating

Base alloy (substrate)

Base alloy (substrate)

Challenge Statement
  • Hard coatings protect against glancing impacts, but fail at normal impacts.
  • Can a combination of hard and soft layers provide protection under a wide array of conditions?
  • Yes, but there is a price to pay
film deposition
Film Deposition
  • Iterative and DOE based development of processing parameters.
  • Separately studied gas flows, substrate bias, rotation, and pressure.
parameter space evaluation
Parameter Space Evaluation

Full factorial study of power and source to substrate distance.

Developed a coating with 3240 HV0.200.

3” source-to-substrate distance at 1200W sputtering power.

Chosen Conditions

contributions to stress
Contributions to Stress






Ceramic (brittle coating)


Base alloy (substrate)


impact mechanics
Impact Mechanics
  • Stiffer materials increase the maximum contact force by decreasing contact time
  • Increase compliance may allow more flexure, but significantly decreases contact force



Goldsmith 1960

influence of layer thickness
Influence of Layer Thickness

Thin layers

Thick layers



super hard coatings
Super Hard Coatings
  • Up to a 2x increase in hardness and elastic modulus
  • Good for low energy (cutting)

Diamond tool coating

Yashar & Sproul 1999

super tough materials
Super Tough Materials

Koehler Theory


Equal layer thickness concentrates stress in the hard layers

Excessive dislocation restriction can lead to cleavage fracture

Experimental data suggest that thinning ductile layer causes increased brittle manner and reduced fracture energy

  • Structure of two layered materials with the elastic moduli as different as possible
  • Hard and soft of equal thickness
  • Each layer <100 atoms thick

Evans and Dalgleish 1992

Hsai et al. 1994

Koehler 1970

tin crn ti superlattice
[TiN/CrN]/Ti Superlattice
  • Multilayers create an ultrahard superlattice
  • Author suggest that poor performance was caused by the brittle nature of the superlattice and interfacial detachment.

Yang et al. 2004

  • Ductile layers must be thin to avoid excessive flexure, but not so thin to cause brittle behavior
  • Thicker hard layers will perform well against small and angular erodents at low speeds
  • Thinner layers will perform poorly against small and angular particles but show marked improvement against larger smooth particles at high speed
support for model
Support for Model


  • Chai & Lawn studied the effects of:
  • Number of layers
  • Interlayer thickness
  • Relative Moduli

Decreasing interlayer thickness

Most multilayer research

As the modulus mismatch increase and the number of layers increase, the interlayer thickness must decrease

Chai and Lawn, 2002

optimizing layer designs
Optimizing Layer Designs
  • Failure for the 1st layer can be with less load than a similar monolithic coating
  • However, failure for the entire coating requires far more load than similar monolithic
  • Multilayer coatings have built in damage tolerance
  • Failure load of the 1st of 10 layers is lower
  • Failure load of the 5th of 10 layers is higher

Chai and Lawn, 2002

design of experiments
Design of Experiments
  • A 3x3 grid of layer designs to quantify the effect of layer design
    • Number of layers
    • Interlayer thickness
  • TiN/Ti
  • TiN/Zr
  • TiN/Hf
  • TiN/Nb

Increasing layers

Increasing Ti Thickness

  • Best result used for interlayer study







equipment innovations
Equipment Innovations
    • Dual venturi design
    • Atmospheric pressure erodent loading
    • No rubbing components
  • In situ feed calibration
  • Extremely efficient accelerating
    • Allow 180 m/s operation
  • Automated process control
  • Calibration
alumina damage progression
Alumina Damage Progression





Slow continuous erosion of monolithic coatings

Local, layer by layer failure of the multilayer coatings





performance against glass beads
Performance againstGlass Beads

Resistance to cracking and flexure

strong benefit of the titanium interlayer
Strong benefit of the titanium interlayer

1.25 vol % Ti

5 vol % Ti

25 vol % Ti

influence of bond layer
Influence of Bond Layer

Another important finding was that the coatings were not too thick to transfer stress through the coating thickness

the monolithic coating with the thickest bond layer offered significant performance benefits over the monolithic coating with the thinnest bond layer.

corroborating evidence




Wood, 1999

Corroborating Evidence
  • Energy must be reflected or absorbed
  • Hard layers deflect glancing impacts
    • Crack under high energy & normal impacts
  • Compliant material deforms to absorb energy
    • Offers little direct erosion resistance
    • Increase coating compliance

Hard (brittle coating)

Base alloy (substrate)

  • The complaint layers in the multilayer coating blunt the crack tip
  • The large difference in elastic moduli creates a barrier to crack penetration and dislocation motion

Base alloy (substrate)

  • Sketch of the mechanics of single layer and multilayer erosion.
  • Impact crater as a results of erosion damage.
  • Optical micrograph of impact crater showing depth of erosion damage
results summary
Results Summary
  • The angularity of the erodent has a significant effect on the failure mode
    • Sharp, Hard  Chipping  Monolithic
    • Round, Friable  Cracking  Multilayer
  • 8L5vol% performed well in every condition
  • TiN/Nb coatings performed the best
  • High poison’s ratio gave the ability to shear, but highly incompressible
  • Erosion resistance is a strong function of layer design
  • Results suggest that an optimum design exists for each erosion condition
  • Testing confirms that low energy performance can be sacrificed to achieve high energy performance
project goals completed
Project Goals Completed
  • Create failure model
  • Present hypothesis
  • Deposit coatings
  • Develop testing equipment
  • Perform jugular experiments
  • Analyze and report data
thank you
Thank you


more topics
More Topics
  • Showed correlations between erosion rate and hardness was a function particle size and indention load