7 research outputs found
Structure and Mechanical Properties of TiAlSiY Vacuum-Arc Coatings Deposited in Nitrogen Atmosphere
The effect of a negative bias potential applied to the substrate on elemental composition, structure,
and mechanical properties of vacuum-arc TiAlSiY nitride coatings is investigated by different methods. It is
ascertained that applying a high (up to –500 V) bias voltage leads to a selective sputtering of target as well as
significant microdeformation of the coating, small-sized growth of crystallites, and their preferred orientation
along the [110] direction. In this case, the coating deposited has a low hardness H = 6.95 GPa and propensity
to intense wear under scratch and tribological tests. Crystallites with stoichiometric composition ~140 nm in
size and [111] preferred orientation perpendicular to the surface of growth are formed at the bias potential
about –200 V, and superhard (H = 49.5 GPa) and wear-resistant coatings are grown under such conditions.
The mechanisms of formation of the structure of multielement coatings are discussed. It is shown that for-
mation of an amorphous phase and nanocrystal [110] texture takes place at a high bias potential owing to the
process of radiation-stimulated selective spraying of the target. Formation of microstrained crystallites 10 nm
in size caused by the weakening of interatomic bonds is observed in the coating under such deposition condi-
tions, and it leads to the decrease in coating hardness and fast destruction during tribological testing. Sub-
stantial bias voltage dependence of deposited coating properties is established in our investigations