Application of Raman Spectroscopy for Analyzing Diamond Coatings on a Hard Alloy

Morphology of Diamond Layers Grown on Different Facets of Single Crystal Diamond Substrates by a Microwave Plasma CVD in CH4-H2-N2 Gas Mixtures

“…The substrate temperature during deposition was about 800 • C as measured through plasma by the Mikron M770 two-color pyrometer. These deposition parameters and the nitrogen concentration in the gas mixture corresponded to deposition regime for nanocrystalline DCs on WC-Co substrates [3]. As the substrate, we used a multifaceted type IIa synthetic SC diamond produced by the high pressure-high temperature (HPHT) gradient method.…”

“…This may introduce a surface defect with a different symmetry of bonds, which gives rise to renucleation or a twin. In this model, the radical concentration ratios [CH 3 3 ] determine the probability of the renucleation event.…”

“…At the end of the 5-min growth session, we measured the Raman spectra (Figure 2a) of the films deposited on each face of the sample [3]. The Raman spectrum on the face {100} contains only the 1st order Raman diamond line at ν R = 1332.4 cm −1 with full width at half magnitude (FWHM) Γ 1/2 = 2.7 cm −1 .…”

“…Diamond coatings (DCs) produced by chemical vapor deposition (CVD) on tungsten carbide WC-Co cutting tools allow a great improvement in the tool performance by extending its lifetime, increasing the machining speed, and providing a better quality of the machined material [1]. The application of bilayered or multilayered micro-and nanocrystalline DCs further enhances the cutting tools' functional properties [2,3]. The upper nanocrystalline layer provides low roughness and low friction coefficient, as well as high bending strength [4].…”

“…For example, the addition of nitrogen allows a transition from microcrystalline diamond (MCD) to nanocrystalline diamond (NCD) coating deposition regimes. As a result, one can obtain smooth bilayered DCs with increased wear resistance by the CVD method for an optimal nitrogen concentration [3]. The N 2 gas added to standard CH 4 -H 2 mixtures strongly enhances the growth rate SC diamond seeds (typically of {100} orientation) [7,8], thus reducing the cost of CVD diamond production.…”