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an opportunity to produce composition materials in the mode of self

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AN OPPORTUNITY TO PRODUCE COMPOSITION
MATERIALS IN THE MODE OF SELF-PROPAGATING HIGHTEMPERATURE SYNTHESIS AND SHOCK-WAVE LOADING
Ch.G. Pak, V.M. Batrashov,
S.V. Skiba, P.I. Serov
Penza State University
Welding engineering and materials technology
department, Penza State University, 40,
Krasnaya Str., 440026, Penza
E-mail: metal@pnzgu.ru
tel., fax (8412) 36-82-98
The objective of the work:
пЃ¬
Producing protective coatings using the
method of gas-dynamic spraying,
improving technological effectiveness of
spraying and reducing the cost of materials
for spraying
One of promising materials is TiB2, titanium boride. Ceramic solids
based on it have high hardness and wear resistance. Their plastic
properties are sufficient for producing protective coatings, but the
main disadvantage of such coatings is abrasion wear. Abrasion wear
is an inadmissible type of destruction as it is characterized by sharp
deterioration of surface layers quality.
The TiB2 powder was pre-screened using the air separator to sort out fractions
with the particle size being 1-6 microns. The nickel powder was screened using the
sieves with the fraction size being 20-40 microns, then Ni and TiB2 powders in the
quantity of 40% and 60% respectively were being mixed in an eccentric mixer for 8
hours with the following powders mechanical activation in a ball mill. After the
mechanical activation compacts with the size of 100x50
and the thickness of up to 10
mm were produced with the help of a hydraulic
press. The compact produced was
being sintered in the argon atmosphere at the
temperature of 1,1300РЎ for 3 hours, then the
particles with the size of 32-50 microns were
ground in a ball mill and then they were used
for spraying. The compact material ground in
the ball mill was later used for plasma spraying
of protective coatings. Spraying was
performed with on-site protection with
the nozzle using the universal plasma
installation UPU-3D
RESULTS
The coating tribological properties analysis showed that under the
conditions of dry gliding friction paired with steel 65G the
developed coatings have low wear values (1.6-3 microns/km) with
sufficiently low friction coefficients (0.18-0.25). It was also stated
that the more the testing velocity, the less the coating wear. Using
the X-ray analysis methods the TiO2 and B2O3 interstitial oxides
were found. These oxides are able to form solid solutions with
each other, thus producing an amorphous film showing low
tendency to adhesive interaction with steel and protecting the
material from damage in the process of friction. So, the TiO2B2O3 oxide film formation conditions high tribotechnical
characteristics and indicates that the process of mechano-chemical
wear is normal.
The pattern of shock-wave loading
1 в€’ electric detonator; 2 в€’ explosive container; 3 в€’ flying plate; 4 в€’ tube;
5 в€’ container; 6 - powder ; 7 в€’ plate-base; 8 в€’ woodchip board; 9 в€’ soil.
Blasting in the open polygon conditions
Explosive container
before explosion
Explosive calculation
To place the explosive carton containers were made. The quarry powder
6ZHV according to GOST 21984-76 was used as an explosive.
The quarry powder 6ZHV is aimed at blasting in the open air.
It contains trotyl as a sensitizer and ammonium nitrate – a matter with feebly
marked explosive properties, decaying during detonation at the speed an order
of magnitude less than powerful individual explosives.
When 6ZHV explodes chemical reactions proceed in several stages.
The protective coating sprayed on a steel plate
РЎС‚3+TiB2-Ni
Microstructure
TiB2 + Ni specimen after shock-wave
loading
TiB2 specimen after mechanical
activation in a ball mill
Conclusions
Producing ceramic solids for protective coatings spraying using the
method of shock-wave loading is not only more profitable
economically, but it also allows producing a coating with better
physical-mechanical properties
Thank you for your attention!
Welding engineering and materials technology
department, Penza State University, 40,
Krasnaya Str., 440026, Penza
E-mail: metal@pnzgu.ru
tel., fax (8412) 36-82-98
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