DBPapers
DOI: 10.5593/sgem2012/s12.v3011

THE PHYSICAL BASES OF ELECTROLYTIC FORMATION OF CHROMIUM- SILICON DIOXIDE NANOCOMPOSITE SYSTEMS IN ELECTROLYTIC COATINGS

G. SH. YAR MUKHAMEDOVA, A .M. DARISHEVA, A .A. MAMAEVA, M. MOLDABAEV, S. P. ZABOTSEV
Wednesday 1 August 2012 by Libadmin2012

References: 12th International Multidisciplinary Scientific GeoConference, www.sgem.org, SGEM2012 Conference Proceedings/ ISSN 1314-2704, June 17-23, 2012, Vol. 3, 515 - 520 pp

ABSTRACT

The main aim of the work is theoretical and experimental research of nanocomposite
systems formation process on the model of chromium electrolytic coatings, ascertainment
of laws and mechanisms of silicon dioxide nano-sized particles influence on the structure
and properties of metal. We researched the process of electrolytic formation of chrome -
silicon dioxide nanocomposite systems and nanostructured composite electrolytic coatings
with silicon dioxide (3-50 nm) used as a dispersed phase. Methods of the research: atomicforce,
raster electronic, optical microscopy, as well as IR-spectrometry, and roentgenstructural
analysis. Estimation of endurance and corrosion resistance was made by weight.
Main results and findings of the present research:
- Analysis of contemporary state and perspective ways of nanotechnology development has
made it possible to propose a new scientific approach for the solving the problem of Cr-
SiO2 nanocomposite systems formation in electrolytic coatings.
- On the basis of the research it has become possible to determine the electrolyte
compositions for chrome - silicion dioxide nanocomposite systems formation, and it has
been established that optimal content of silicon dioxide in the electrolyte is 20 g/l. A larger
content of the second phase will cause sludging, dramatic lessening of current output, while
lower content of SiO2 will not bring marked changes of the microstructure and getting the
required properties of the nanocomposite system.
- Mechanisms and natural laws were ascertained to determine influence of temperature,
current density and ultrasonic exposure modes on the parameters of metal plating by nano-
CEC. It has been shown, that increase of temperature and current density causes decrease of
current output, and periodical ultrasonic exposure enables formation of nanocomposite
systems with dense, finely crystalline and porous chromium matrix.
- Researches with atomic-force, electronic and optical microscopy have revealed
uncharacteristic for metals (chromium in particular) petal-like, globular structures
predetermined by high activity of nano-sized particles of silicon dioxide.
- Radiographic studies of nanocomposite systems formed at different temperatures
established that changes of microhardness depend on the fact that within 298-323 K
hexagonal chromium hydride (CrH) having microhardness 10,5-12 GPa deposits. In the
temperature interval of 338-348 K mainly FCC chromium hydride with microhardness
about 6-10 GPa deposits.

Keywords: nanocomposite systems, atom-force microscopy, nano-sized particles, nanocomposition
electrolytic coatings (nano-CEC), microhardness.