THE GROWTH OF WHISKERS FROM VAPOUR PHASE.

Abstract

The factors influencing the growth of whiskers from the vapour are reviewed. Reactions are classified as either physical or chemical, the latter being subdivided as homogeneous or heterogeneous. The stages of growth are taken to be (i) nucleation, arguments being presented that this is normally a surface process, (ii) growth from the nuclei, critical analyses being made of the screw-dislocation and VLS mechanisms, and of the supersaturation criteria for the physical growth process, and (iii) termination, about which little is known, but which may be due to dislocation movement or surface poisoning. Metallic and ceramic whiskers resulting from chemical reactions are reviewed, and the E.R.D.E. process for the growth of silicon nitride analysed. Thermodynamic and kinetic criteria for the chemical reaction taking place at the whisker tip are suggested, these criteria being regarded as the chemical analogue to the supersaturation conditions for the physical growth process. (Author)

Document Details

Document Type
Technical Report
Publication Date
Jan 06, 1967
Accession Number
AD0661496

Entities

People

  • T. J. Lewis

Tags

Communities of Interest

  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Analogs
  • Ceramic Materials
  • Chemical Analogs
  • Chemical Reactions
  • Diseases And Disorders
  • Dislocations
  • Nucleation
  • Poisoning
  • Supersaturation

Readers

  • Materials Science (Mechanical Engineering).
  • Materials Science and Engineering.
  • Theoretical Analysis.