Ceramic materials testing and modeling

PDF Version Also Available for Download.

Description

Certain refractory ceramics (notably oxides) have desirable properties suitable for the construction of ceramic waste containers for long term use in nuclear waste disposal applications. In particular, they are far less prone to environmental corrosion than metals under realistic repository conditions. The aqueous corrosion rates of oxides such as magnesium aluminate spinel (MgAl{sub 2}0{sub 4}) and alumina (Al{sub 2}0{sub 4}) fall in the range of a few millimeters per million years. Oxide ceramics are also not likely to be subject to microbiologically influenced corrosion, which apparently can attack most, if not all, of the available engineering metals. Ceramics have a ... continued below

Physical Description

22 p.; Other: FDE: PDF; PL:

Creation Information

Wilfinger, K. R., LLNL April 30, 1998.

Context

This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided by UNT Libraries Government Documents Department to Digital Library, a digital repository hosted by the UNT Libraries. More information about this report can be viewed below.

Who

People and organizations associated with either the creation of this report or its content.

Sponsor

Publisher

Provided By

UNT Libraries Government Documents Department

Serving as both a federal and a state depository library, the UNT Libraries Government Documents Department maintains millions of items in a variety of formats. The department is a member of the FDLP Content Partnerships Program and an Affiliated Archive of the National Archives.

Contact Us

What

Descriptive information to help identify this report. Follow the links below to find similar items on the Digital Library.

Description

Certain refractory ceramics (notably oxides) have desirable properties suitable for the construction of ceramic waste containers for long term use in nuclear waste disposal applications. In particular, they are far less prone to environmental corrosion than metals under realistic repository conditions. The aqueous corrosion rates of oxides such as magnesium aluminate spinel (MgAl{sub 2}0{sub 4}) and alumina (Al{sub 2}0{sub 4}) fall in the range of a few millimeters per million years. Oxide ceramics are also not likely to be subject to microbiologically influenced corrosion, which apparently can attack most, if not all, of the available engineering metals. Ceramics have a reputation for poor mechanical performance and large, impermeable objects are not easily fabricated by most current fabrication methods. As a result, the most promising approach for incorporating ceramics in large waste packages appears to be to apply a high density ceramic coating to a supporting metallic structure. Ceramic coatings 2048 applied by a thermal spray technique can be made effectively seamless and provide a method for final closure of the waste package while maintaining low average temperatures for the entire assembly. The corrosion resistance of the ceramic should prevent or delay water penetration to the underlying metal, which will in turn provide most of the mechanical strength and toughness required by the application. In this way, the major concerns regarding the ceramic coating become ensuring it is impervious to moisture, its adherence and its resistance to mechanical stresses during handling or resulting from rock fall in the repository. Without water, electrochemical corrosion and microbiologically influenced corrosion processes are considered impossible, so a complete coating should protect the metal vessels for far longer than the current design requirements. Even an imperfect coating should extend the life of the package, delaying the onset and reducing the severity of corrosion by limiting the transport of water and oxygen to the ceramic-metal interface. Thermal spray techniques for ceramic coating metallic structures are currently being explored. The mechanics of thermal spray resembles spray painting in many respects, allowing large surfaces and contours to be covered smoothly. All of the relevant thermal spray processes use a high energy input to melt or partially melt a powdered oxide material, along with a high velocity gas to impinge the molten droplets onto a substrate where they conform, quench, solidify and adhere mechanically. The energy input can be an arc generated plasma, an oxy-fuel flame or an explosion. The appropriate feed material and the resulting coating morphologies vary with technique as well as with application parameters. To date on this project, several versions of arc plasma systems, a detonation coating system and two variations of high velocity oxy-fuel (HVOF) fired processes have been investigated, operating on several different ceramic materials.

Physical Description

22 p.; Other: FDE: PDF; PL:

Notes

OSTI as DE98057888

Source

  • Other Information: PBD: 30 Apr 1998

Language

Item Type

Identifier

Unique identifying numbers for this report in the Digital Library or other systems.

  • Other: DE98057888
  • Report No.: UCRL-ID--130734
  • Grant Number: W-7405-ENG-48
  • DOI: 10.2172/674999 | External Link
  • Office of Scientific & Technical Information Report Number: 674999
  • Archival Resource Key: ark:/67531/metadc711998

Collections

This report is part of the following collection of related materials.

Office of Scientific & Technical Information Technical Reports

What responsibilities do I have when using this report?

When

Dates and time periods associated with this report.

Creation Date

  • April 30, 1998

Added to The UNT Digital Library

  • Sept. 12, 2015, 6:31 a.m.

Description Last Updated

  • May 18, 2016, 5:30 p.m.

Usage Statistics

When was this report last used?

Yesterday: 0
Past 30 days: 0
Total Uses: 3

Interact With This Report

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Wilfinger, K. R., LLNL. Ceramic materials testing and modeling, report, April 30, 1998; California. (digital.library.unt.edu/ark:/67531/metadc711998/: accessed September 22, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.