CUMULATIVE SYNTHESIS OF SUPERHARD COATINGS S.A. Kinelovskii 1,4, S.A. Gromilov 2,4, M.A. Korchagin 3, Yu.N. Popov 4, and K.K. Maevskii 1 1- Lavrent'ev Institute of Hydrodynamics of Russian Academy of Sciences; 2 - Nikolaev Institute of Inorganic Chemistry of Russian Academy of Sciences; 3- Institute for Solid State Chemistry and Mechanochemistry of Russian Academy of Sciences; 4 - Novosibirsk State University This work was supported by the Russian Foundation for Basic Research (project No ) EPNM–2012 May 2–5, 2012, Strasbourg, France

CUMULATIVE SYNTHESIS or SHAPED CHARGE SYNTHESIS 2

Area of the forming of cubic phase β-WC on the plane of phase States of tungsten-carbon. Area of the forming of cubic phases of TiC on the plane of phase States of titanium-carbon. 3 S. A. Kinelovskii, K. K. Maevskii “Simple Model for Calculating Shock Adiabats of Powder Mixtures” Combustion, Explosion, and Shock Waves, Vol. 47, No. 6, 2011

Grinding surface on steel using mixture of W- Sibunit-Co Sample construction staging area between the surface and the unperturbed steel matrix mechanically activated composites 30% (wt.) (WC + 30%(wt.)TiC)/70%(wt.) (Ni + Cr) (W + 1,1 C) + 20 %(wt.)Co 4

For the mixture W + C + Co micro hardness of surface layer H v = 13 – 20 GPa for a single evaporation on steel target. For the composition WC+ TiC +(Ni-Cr) micro hardness of surface layer H v = 10 – 22 GPa for a single evaporation on to steel target. (pure steel – H V = 1,1 GPa). Cover fixed cubic phase based on chromium (Cr), absent in the original mixture. 1 2 The use of mechanically activated 30% (wt.) (WC + 30%(wt.)TiC)/70%(wt.) (Ni + Cr) composites for cumulative deposition onto titanium substrate automatically resulted in formation of a functionally graded coating in which the near- surface layer was TiC-rich while the inner layers, WB-rich. 5

Consider the following case where new phases are formed in contact with the surface of the particle flux cumulative targets. When the cumulative particle flux with metal obstacle on the surface of obstacle may to form a kind of layer - covering. On the one hand, this layer can contain any phase synthesized under collapsing shape charge. On the other hand, the interaction of particles with the material obstacle possible synthesis of new phases and then coating is integrated in the crystal lattice. In this case, one may speak of cumulative synthesis. 6

7 Carbon (C) + ammonium nitrate ( NH 4 NO 3 ) in titanium target,  = 45  2θ, degree (111) c (200) c (100) g (101) g (002) g Intensity

8 Measuring micro hardness For lining of mixture B–NH 4 NO 3 mixture (1 : 2 by volume, α = 20 0 ) the average surfaces microhardness equals 18GPa and maximum value = GPa (from here onwards, the load 200 g) when you go to the triple interaction of these values were 39.0, respectively, and 44.5 GPa. For mixtures of graphite + NH 4 NO 3 transition to three-fold interaction has led to an average micro hardness 29.5 GPa, maximum 35.4 GPa. In the search for other mixed trains to shaped charge lining, graphite was replaced by sibunit. -Use a mixture of sibunit + NH 4 NO 3 (1 : 2 by volume) has the average value of micro hardness layer 41.2 GPa at maximum height 41.9 GPa, suggesting a high degree of homogeneity of formed high solid layer.

Decomposition of precursor shaped charge currents and the synthesis of new compounds mixture of powders (TiB 2 +B 4 C+(Ti +2B)+W)  TiB 2, β-WB, W 2 B, W Inset shows changing of diffraction pattern after grinding samples Roentgen-phase analysis showed the presence of four crystalline phases in terms of elementary cells (EC) close to the TiB 2, β-WB, W 2 B, W. Intensity 2θ, degree 9

mixture of powders (TiB 2 +B 4 C+W)  TiB 2, β-WB, W 2 B, W At the top curve insert shows the classification of fundamental diffraction lines detected phases, on the bottom curve - depth-variation of phase-change. Decomposition of precursor shaped charge currents and the synthesis of new compounds Analysis of the results shows that are used with collapsing lining pressure and temperature in this case is insufficient to break the compound TiB 2 – practically all of diboride titanium saved. Phase B 4 C all decays and freed boron forms two phases of boride of tungsten. 2θ, degree 10 I, int./c 2θ, degree I, int./c

Estimation of pressure and temperature to be used in shaped charge currents for some mixtures In these experiments, received coverage on titanium, micro hardness (Hv = 42 Hpa) is significantly higher than the micro hardness phases of the borides of titanium and tungsten 11 P, Gpa