Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels
This presentation is the property of its rightful owner.
Sponsored Links
1 / 13

Young’s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels PowerPoint PPT Presentation


  • 40 Views
  • Uploaded on
  • Presentation posted in: General

Young’s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels. Huixing Zhang, Eddie.Lopez-Honorato, Athar Javed, Jill Meadows, Ping Xiao Material Science Centre, School of Materials, the University of Manchester, M1 7HS, UK. Application in TRISO coating.

Download Presentation

Young’s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

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


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

Young’s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

Huixing Zhang, Eddie.Lopez-Honorato, Athar Javed, Jill Meadows, Ping Xiao

Material Science Centre, School of Materials, the University of Manchester, M1 7HS, UK


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

Application in TRISO coating


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

Contents

  • PyC coatings were deposited on spherical particle using in the TRISO fuel

  • Deposition temperature was varied from 1250 - 1450 °C

  • Mechanical properties were measured using Nanoindentation

  • Microstructure was shown in as deposited, and heat treated PyC coatings, using SEM, XRD and TEM.


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

PyC coatings preparation and properties

PyC coatings density under different deposition conditions

Orientation angle Domain size La (in graphene plane) and Lc (c-direction)


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

PyC coatings preparation and properties (Continued)

PyC orientation angle and density

PyC domain size and density relationship


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

Mechanical properties in as-deposited PyC

2 μm

Density effect

Low density PyC, the microstructure difference does not affect theYoung’s modulus.

(c)

(a)

(b)

(b)

(a)

(c)

Domain size: 1.7 nm domain size: 1.1 nm domain size: 1.1 nm


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

2 μm

Density effect (continued)

(c)

(a)

However, in high density region, the mechanical properties do not correlate directly with the density.

Three kinds of microstructure were found in high density PyC.

In low density PyC, both the Young’s modulus and hardness increase with the density linearly.

(b)

(c)

(b)

(a)

Laminar

Granular

Mixture of granular and laminar


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

Orientation angle, domain size and microstructure effect

The Young’s modulus and hardness in high density PyC are not dominate by any single element, e.g. density, orientation angle and domain size.

The only trend is:

Young’s modulus and hardness increase with microstructure change from granular to laminar, and then to mixture structure.

Since the particle bonding area and bonding strength dominates the mechanical properties of porous material [1,2]. We presume that in laminar structure the bonding area is bigger than in granular structure, while granular structure has stronger bonding strength. There is a maximum point where the maximum bonding area and strength could be reached, then the mechanical properties are maximum.

[1] J.L.Kaae, Carbon, 1971, Vol. 9, pp. 291-299

[2] J.C.Bokros and R.J.Price, carbon, 1966, vol 3, pp, 503-509


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

Thermal treatment effect on mechanics and structure

Young’s modulus and hardness

High density

Low density

Hardness

1300

High density sample mechanical properties decrease dramatically;

Young’s modulus

1300

Slightly changes could be seen in low density PyC; the mediate density specimen are experiencing the decrease.


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

Domain size change

Laminar

Graphitization process in dense PyC is quicker than in porous structure, because porous structure has stronger cross link than dense PyC.

1300

1300

The increase of Lc in laminar structure is more than granular and mixture structure PyC;


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

2 μm

200 μm

Microstructure change

In high density laminar structure PyC 1250 C50% Acetylene

Microstructure change is not uniform through the whole layer in laminar structure PyC.

After 1800 C heat treatment As-deposited


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

2 μm

Microstructure change (continued)

In high density granular structure PyC, 1350 C33% Acy/Prop

Before heat treatment After heat treatment

SAED with 200 nm aperture; the crystal phase nucleation, did not see the diffraction angle change.

SAED with 200 nm aperture; OA: 43°


Young s modulus and hardness of pyrolytic carbon coatings used for containment of nuclear fuels

Summary

  • With low density (<1.9 g/cm3), the Young’s modulus and hardness increase with the increase of the density linearly.

  • In high density PyC, the laminar and granular microstructure are more likely to dominate the mechanical properties; they are not the function of single element, such as density, domain size and orientation angle.

  • Thermal treatment promotes the crystalline process in high density PyC, which decreased the mechanical properties dramatically.

  • Non-uniform microstructure change was found in laminar structure high density PyC after heat treatment.


  • Login