Высокоэнергетическая обработка материалов
171
The cross-sections of puncture zones gained in the same conditions (fig. 6)
on surfaces of a silicon monocrystal plate are in the form of square. The width of a
wall of such square changes from 1.6⋅10
-5
m to 2.3⋅10
-5
m (fig. 1). Thus, the cross-
section of puncture aperture in silicon and in glass has approximately equal sizes.
Hence, the transverse size of the microstream created in equal conditions in the
mode of super deep penetration remains constants at the set material of an obstruc-
tion. It sounds paradoxical but as plastic aftereffect on puncture geometry in glass
is more significant, in comparison with aftereffect in silicon it is necessary to ad-
mit, that the real geometry of a stream cross-section is in the form of a square. The
bandwidth of oscillations in defect (fig. 7) is less than in analogous conditions in
glass (fig. 3), also is about 3.5⋅10
-5
m. Thus, at using glass as a material for electric
field record the bandwidth of oscillations increases in 11.4 times. The distance be-
tween phases of oscillation curve of damages in Si monocrystal is approximately
equal to 8.5⋅10
-5
m, which is approximately 0.94 % from analogous measurement
made on glass. The form of a strip of damages also corresponds to sawtooth
change of parameters of the electromagnetic field controlling movement of a dense
plasma microstream.
Microhardness of various glasses is 400-1200 MPa. Average hardness of
glass is approximately 0.7⋅10
9
N/m
2
, i.e. less than 70% from hardness of Si
monocrystal. Thus, increase in an amplitude of oscillation of plasma microstream
on a glass sample surface in 11 times is impossible to explain only by decrease in
hardness of an obstruction material. Depth of stream penetration in a surface of the
glass sample (fig. 3b) not less than a depth of penetration in surface of silicon
monocrystal (fig. 7а). If to use minimization principle and to accept, that damage
volume on a glass surface (V
g
) more than damage volume on a surface of a silicon
monocrystal (V
Si
)
only in 11 times then at equal speed of a dense plasma micro-
stream the energy spent for damages, will depend on a relationship of density of
glass and silicon ρ
g
/ρ
Si
≈ 1,1. Crude comparison of kinetic energy of the micro-
stream spent for damage of glass surface and of a silicon monocrystal surface, tak-
ing into account a difference between these materials in hardness (the characteristic
of durability of a material at first approximation) allows to reveal presence of
power abnormality E
g
/E
Si
≈8.4 times. Such abnormality in the given conditions can
be explained only by difference in an interaction time between a stream and elec-
tric field at considered variants.