SYNTHESIS OF AL2O3 CONDENSATES FROM IMPULSE PLASMA

The synthesis of Al2O3 Condensates was carried out in a coaxial impuls e plasma generator. A complex metal ceramic (Al-Al2O3) hot electrode f unctioned as the source of material. In some selected experiments a ce ramic (Al2O3) ring was used as an additional source of Al2O3 (or AlO, Al, O) vapour. The impulse plasma was generated by discharging a 100-2 00 muF capacitor battery charged to a voltage of 3 kV. The plasma gas (O2 or Ar) pressure was 15-30 Pa. As a result of the impulse plasma pr ocess, continuous ceramic coatings were condensed on non-heated Ni sub strates. Surprisingly, the monotropic metastable Al2O3 phases were the only phases found in the condenstate material (no stable alpha-Al2O3 phase and/or Al occurred even when argon was used as the plasma gas). This can be explained by the effect exerted by the surface pressure, w hich was as high as 0.4 G Pa.