scholarly journals INFLUENCE OF COPPER SUBLAYER ON NUCLEATION OF DIAMOND CRYSTALS ON SURFACE OF TUNGSTEN CARBIDE

2018 ◽  
Vol 59 (8) ◽  
pp. 85 ◽  
Author(s):  
Dmitriy S. Vokhmyanin
Keyword(s):  
Raman Spectroscopy ◽  
Phase Composition ◽  
Tungsten Carbide ◽  
Layer Structure ◽  
Chemical Deposition ◽  
Diamond Crystals ◽  
Negative Temperatures

The buffer copper sublayer on the surface of tungsten carbide was obtained with the chemical deposition from aqeous solutions. With the using the methods of SEM, AFM, XRF it was established that at temperature of 23 °C the layer structure is porous that do not observed at negative temperatures. The sublayer structure influences the character of nucleation of diamond crystals and their form. The phase composition was determined with Raman spectroscopy. The spectrum shows the lines of diamond (1334 cm-1), sp2 of carbon and trans-polyacetylene (1170 сm-1). 

Phase composition of copper nitride coatings examined by the use of X-ray diffraction and Raman spectroscopy

2018 ◽  
Vol 1165 ◽  
pp. 79-83 ◽  
Author(s):  
Katarzyna Nowakowska-Langier ◽  
Rafal Chodun ◽  
Roman Minikayev ◽  
Sebastian Okrasa ◽  
Grzegorz W. Strzelecki ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Phase Composition ◽  
X Ray Diffraction ◽  
Copper Nitride ◽  
X Ray ◽  
Nitride Coatings

Composition Controlled Synthesis and Raman Analysis of Ge-Rich SixGe1–x Nanowires

2008 ◽  
Vol 8 (6) ◽  
pp. 3153-3157 ◽  
Author(s):  
P. Meduri ◽  
G. U. Sumanasekera ◽  
Z. Chen ◽  
M. K. Sunkara
Keyword(s):  
Raman Spectroscopy ◽  
Phase Composition ◽  
Vapor Phase ◽  
Room Temperature ◽  
Nucleation And Growth ◽  
Accurate Estimation ◽  
Controlled Synthesis ◽  
Raman Analysis ◽  
Bulk Nucleation ◽  
Alloy Nanowires

Here, we report the synthesis of SixGe1–x nanowires with x values ranging from 0 to 0.5 using bulk nucleation and growth from larger Ga droplets. Room temperature Raman spectroscopy is shown to determine the composition of the as-synthesized SixGe1–x nanowires. Analysis of peak intensities observed for Ge (near 300 cm–1) and the Si-Ge alloy (near 400 cm–1) allowed accurate estimation of composition compared to that based on the absolute peak positions. The results showed that the fraction of Ge in the resulting SixGe1–x alloy nanowires is controlled by the vapor phase composition of Ge.

Preparation of Conductive Tungsten Carbide Layers for SiC High Temperature Applications

1999 ◽  
Vol 572 ◽  
Author(s):  
H. Romanus ◽  
V. Cimalla ◽  
S. I. Ahmed ◽  
J. A. Schaefer ◽  
G. Ecke ◽  
...  
Keyword(s):  
High Temperature ◽  
Chemical Composition ◽  
Tungsten Carbide ◽  
Electrical Resistance ◽  
Single Phase ◽  
Specific Resistance ◽  
Layer Structure ◽  
Carbide Formation ◽  
Pure Hydrogen ◽  
Dc Magnetron Sputtering

ABSTRACTThin tungsten carbide films of different compositions were prepared by DC magnetron sputtering of tungsten and carbon and subsequent annealing in different environments. The onset of carbide formation was around 800°C. Annealing in a pure hydrogen ambient generally results in carbon depletion in the layers with the formation of a dominant W2C phase. Adding propane enhances the carbon content in the layers and stimulates the formation of the WC phase. On silicon nitride substrates, variation of the propane concentration in an annealing environment allows a continuous alteration of the layer structure between polycrystalline single phase WC and a mixed layer with dominant W2C and with it, the adjustment of different values of the electrical resistance. In contrast, on thin (100)SiC layers a textured W2C phase was grown after annealing in propane/hydrogen at 900°C whereas at higher temperatures the formation of silicides was observed. In addition, the chemical composition and the temperature dependence of the electrical specific resistance were investigated and are also discussed.

High Temperature Functionalization and Surface Modification of Nanodiamond Powders

2007 ◽  
Vol 1039 ◽  
Author(s):  
Vadym N. Mochalin ◽  
Sebastian Osswald ◽  
Cristelle Portet ◽  
Gleb Yushin ◽  
Christopher Hobson ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Phase Composition ◽  
High Temperature ◽  
Surface Chemistry ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
High Temperature Annealing ◽  
Treatment Techniques ◽  
Infra Red ◽  
Potential Applications

AbstractHigh temperature annealing in vacuum, air, hydrogen, chlorine, and ammonia are described as a means to change surface chemistry and phase composition of nanodiamond powders of three different grades, which have different sp2/sp3 carbon ratios. The changes in surface chemistry and phase composition of the powders are analyzed using Raman spectroscopy and Fourier Transform Infra Red (FTIR) spectroscopy. Advantages and limitation of high-temperature treatment techniques as well as potential applications of the gas-treated nanodiamond powders are discussed.

scholarly journals Features of the diamond films growth on the tungsten carbide surface by a copper underlayer

2019 ◽  
pp. 72-81
Author(s):  
D. S. Vokhmyanin ◽  
S. A. Oglezneva
Keyword(s):  
Surface Layer ◽  
Phase Composition ◽  
Hard Alloy ◽  
Diamond Film ◽  
Diamond Films ◽  
Surface Preparation ◽  
Growth Stages ◽  
Compressive Stresses ◽  
Diamond Crystals ◽  
Cuso4 Solution

Surface preparation is a prerequisite for ensuring the required properties of a diamond film obtained by gas-phase deposition. The paper considers the effect of temperature and concentration of the etchant CuSO4 on the structural and phase composition of the surface of hard-alloy materials. The structural and phase composition of a continuous polycrystalline diamond film at its growth stages was also studied. Adhesion of the obtained diamond films to the surface of carbide materials was qualitatively determined. It has been established that surface treatment of a hard alloy in a CuSO4 solution at a temperature t = 23 °C leads to unequal removal of the cobalt bond with chipping of WC grains and the formation of a porous structure in the surface layer of the WC–6%Co alloy. The treatment with an etchant CuSO4 at t = –2 °С ensures uniform etching of the Co-bond along the WC grain boundaries and the formation of a chemically uniform surface. The orientational growth and adhesion of the diamond film depend on the elemental composition of the surface of the WC–Co alloy after treatment with a CuSO4 solution. If the treatment was carried out at a tsolution = 23 °C, then during the synthesis of the diamond film, the removal of copper from the defective surface layer of WC is difficult. This provides the multidirectional growth of diamond crystals in the film in two directions: <111> and <110>, which causes critical biaxial compressive stresses (2,5 GPa) and leads to low adhesion of the film to the surface of the hard alloy. If the treatment was carried out at tsolution = –2 °C, then the orientational growth of diamond crystals in the film occurs in one preferential crystallographic direction <111>. It reduces the biaxial compressive stresses (1,7 GPa) and increases the adhesive adhesion of the film to the surface of the hard alloy . The structure defect, calculated from the ratio of the lines of integrated intensities I1333 / I1580 using the Raman spectroscopy, decreases with concentration growth for negative temperatures and increases for positive ones of CuSO4 solution during surface preparation.

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