QUALITY OF MECHANICAL TREATMENT OF SYNTHETIC DIAMOND JEWELRY

  • A.V. Nozhkina JSC Research Institute of Natural, Synthetic Diamonds and Instrument VNIIALMAZ
  • І.І. Vlasov Prokhorov General Physics Institute of RAS
  • V.G. Ralchenko Prokhorov General Physics Institute of RAS
  • A.A. Khomich Prokhorov General Physics Institute of RAS
  • E.V. Zavedeev Prokhorov General Physics Institute of RAS
  • E.S. Khramchenkova National University of Science and Technology MISIS
  • S.A. Ramazanova National University of Science and Technology MISIS
Keywords: single crystals of laboratory-grown diamonds, laboratory-grown diamonds, HPHT-diamonds, surface polishing, machining, roughness, morphology, microstructure, faceting, cutting tools, superhard materials, surface roughness, HTHP-diamond processing

Abstract

Studies presents results of the mechanical processing of synthetic diamonds Ib and IIa on the quality of the jewelry inserts.

Presample diamond Ib was subjected to thermobaric treatment. Using Infrared spectroscopy（IR）, Raman spectroscopy and photoluminescence (PL) researchers have investigated the defect-appropriate composition of diamond crystals of group Ib before and after machining. The results of measurements of spectral characteristics for jewelry inserts made of synthetic diamonds Ib and IIa were also obtained.

The Raman and PL spectra were held on «Horiba LabRAM HR800» spectrometer using a semiconductor laser with a wavelength of 473 nm. The IR absorption spectra were recorded on «Perkin Elmer Spectrum 100 FT-IR» spectrophotometer in the 450-4000 cm-1 range. The study of the defect-impurity composition of crystals of synthetic diamonds before and after machining showed the presence of defectimpurity NV0 and NV- centers in various concentrations on the treated planes. A-center and H3-center were absent in the IR-spectra and in the PL-spectra before machining the insert. Analysis of the surface of the inserts after machining showed the presence of a new, previously undiagnosed H3-center (A-center and a vacancy). The presence of an H3- center after treatment suggests that it could have been formed during the process of faceting, as the surface has a high-temperature and highpressure in the contact zone. It was found that the width of the peak of the Raman spectra at its halfheight of 2.7 cm-1 did not noticeably change after HPHT and mechanical processing This means that the structure of the investigated synthetic diamonds and their compliance with natural analogues.

The study of the surface and surface roughness using an optical interference microscope "NEW LOOK - ZYGO 5000" showed that polycrystalline crystals and nanodiamonds make it possible to obtain roughness of nanoscale particles, the roughness value (Ra) is 2.2 nm in areas and 3.7 nm. on the entire surface of the face. The results of measurements of the quality of the treated surface of single-crystal synthetic diamonds IIa showed a roughness value (Ra) is 1.04 nm over the entire surface of the face.

Published
2020-09-21
Issue
Vol 23 No 1 (2020): Tooling materials science
Section
Instrumental, structural and functional materials based on diamond and cubic bor