A TECHNIQUE FOR THE MICROSTRUCTURAL EXAMINATION OF POLYCRYSTALLINE GRAPHITES

Technical Report · Sun Feb 01 04:00:00 EST 1959

OSTI ID:4207104

Tarpinian, A; Gazza, G E

The application of a metallographic technique for the nucrostructural study of polycrystalline graphite bodies is presented. The porous nature of these bodies presents a problem during the grinding and polishing operations which tend to break-down the pore walls, causing destruction and smearing of the original structures. To prevent thus smearing, a technique for impregnating the porous structure with a resin that hardens at room temperature was used to reinforce the graphite specimens. This operation showed significant improvement in polishing efficiency and preservation of microstructure. Although some structure was visible upon microscopic examination after polishing, finer detail was brought out by etching wtth a solution of potassium dichromate in concentrated phosphoric acid. This etchant reacted quite readily with the graphite surface, yet at a rate that was easily controlled. A variety of photomicrographs, obtained using the techniques described, is presented and discussed. (auth)

• Research Organization: Watertown Arsenal Lab., Mass.
• NSA Number: NSA-14-006686
• OSTI ID: 4207104
• Report Number(s): AD-210086; WAL-TR-132.5/1
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

CHEMICAL REACTIONS
CHROMIUM OXIDES
CLEANING
CONFIGURATION
CONTROL
CRYSTALLOGRAPHY
CRYSTALS
EFFICIENCY
ETCHING
GRAPHITE
GRINDING
IMPREGNATION
METALLOGRAPHY
METALS
CERAMICS AND MATERIALS
PHOSPHORIC ACID
PHOTOGRAPHY
POROSITY
POTASSIUM COMPOUNDS
RESINS
SOLUTIONS
SURFACES
TEMPERATURE
USES