| Abstrakt: |
Composite materials based on polytetrafluoroethylene (PTFE) and natural technical diamond powders from Yakutia diamond deposits are developed. It is shown that the compositions based on PTFE and a technical diamond powder at a content of up to 60 wt.%, due to their good physicomechanical characteristics, low friction coefficient, and good wetting of diamond particles by polymer, make is possible to create abrasive tools for polishing and grinding hard metals and semiprecious and precious stones with high serviceability and operational life combined with a considerable increase in the quality of treated surfaces and operational stability of the tools. It is found that PTFE, being a more elastic and softer matrix than the traditional ones, exhibits a self-sharpening effect of diamond grains upon grinding hard surfaces, when the grains go deep into the elastic matrix, the matrix wears out, and the working part of the tool becomes enriched with the diamond powder. These conclusions are confirmed by electron microscopic investigations. It is shown that the introduction of ultradisperse fillings (up to 2 wt.%) into such compositions allows us to improve the characteristics of abrasive tools considerably, especially for grinding hard semiprecious stones. The physicomechanical and frictional characteristics of the compositions and specific examples of their application in the jewelry industry and in stone working are discussed. [ABSTRACT FROM AUTHOR] |
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