MECHANISM FOR THE ENVIRONMENTAL CONTROL OF DRILLING IN MAGNESIUM OXIDE AND CALCIUM FLUORIDE MONOCRYSTALS

THE EFFECTS OF CERTAIN LIQUID ENVIRONMENTS ON THE PENETRATION OF A CARBIDE SPADE DRILL, AND ON THE MOBILITY OF NEAR-SURFACE EDGE DISLOCATIONS IN FRESHLY CLEAVED MAGNESIUM OXIDE AND CALCIUM FLUORIDE MONOCRYSTALS, HAVE BEEN DETERMINED AT ROOM TEMPERATURE. THE ENVIRONMENTS USED WERE WATER, TOLUENE, DMF, DMSO, DMF-DMSO SOLUTIONS, N-ALKANES RANGING FROM HEPTANE TO HEXADECANE, AND AQUEOUS SOLUTIONS OF ALUMINUM CHLORIDE. IT WAS FOUND THAT DRILLING EFFICIENCY AND NEAR-SURFACE DISLOCATION MOBILITY ARE DIRECTLY RELATED, AND THAT "SOFTENING" ENVIRONMENTS FACILITATE CRACK INITIATION IN MAGNESIUM OXIDE. THE N-ALKANES HAVE ALSO BEEN FOUND TO BE EXTREMELY SURFACE ACTIVE WITH RESPECT TO MAGNESIUM OXIDE AND CALCIUM FLUORIDE SURFACES. IT IS PROPOSED THAT ADSORBED SURFACE-ACTIVE SPECIES CONTROL THE DRILLING BEHAVIOR OF MAGNESIUM OXIDE AND CALCIUM FLUORIDE -- AND PERHAPS OF OTHER NOTCH-SENSITIVE NONMETALLIC SOLIDS (MINERALS) ALSO -- AS A CONSEQUENCE OF THEIR INFLUENCE ON THE FLOW AND FLOW-DEPENDENT FRACTURE PROPERTIES OF THE NEAR-SURFACE REGIONS OF THESE SOLIDS. POSSIBLE EFFECTS OF ADSORPTION-INDUCED REDUCTIONS IN SURFACE FREE ENERGY ARE OF MINOR IMPORTANCE. /AUTHOR/

  • Supplemental Notes:
    • 30 Pp, 10 FIG, 1 TAB, 28 REF
  • Corporate Authors:

    Martin Marietta Corporation

    Res Inst Advanced Studies
    ,   USA 
  • Authors:
    • Westwood, A R
    • Goldheim, D L
  • Publication Date: 0

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Filing Info

  • Accession Number: 00229733
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 15 2004 2:15AM