HIGH-TEMPERATURE OXIDATION OF PURE TITANI UM IN CO2 ATMOSPHERE

The oxidation behavior of pure titanium has been investigated in the t emperature range of 1000K to 1300K in CO2 or Ar-10%CO2 atmosphere. Opt ical microscopy, electron probe microanalyses and X-ray measurements o n the oxide scales formed during oxidation indicated that their struct ures were nearly independent of temperatures and atmospheres employed; the scale consisting of two layers, external one and internal one, ha ve the rutile structure. The parabolic rate laws were confirmed on gro wth of external scale laver and the permeation depth of oxygens in tit anium with the apparent activation energies, 266 and 226kJ/mol, respec tively. The rate determining diffusion species in these oxidation-proc esses were discussed.