AN OPPORTUNITY TO PRODUCE COMPOSITION MATERIALS IN THE MODE OF SELF-PROPAGATING HIGH-TEMPERATURE SYNTHESIS AND SHOCK-WAVE LOADING. Ch.G. Pak , V.M. Batrashov, S.V. Skiba, P.I. Serov Penza State University.
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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: [email protected]
tel., fax (8412) 36-82-98
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 1,1300С 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
RESULTS sort out fractions
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 TiO2-B2O3 oxide film formation conditions high tribotechnical characteristics and indicates that the process of mechano-chemical wear is normal.
The pattern of shock-wave loading sort out fractions
1 − electric detonator; 2 − explosive container; 3 − flying plate; 4 − tube;
5 − container; 6 - powder ; 7 − plate-base; 8 − woodchip board; 9 − soil.
Blasting in the open polygon conditions sort out fractions
Explosive container before explosion
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 sort out fractions
Microstructure sort out fractions
TiB2 + Ni specimen after shock-wave loading
TiB2specimen after mechanical activation in a ball mill
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