In situ measurement system for deformation and solidification phenomena of yttria-stabilized zirconia droplets impinging on quartz glass substrate under plasma-spraying conditions

The authors have developed an in situ measurement system for precise one-to-one correlation between splat morphology and thermal history during particle impingement on a temperature-controlled substrate inside an airtight chamber under plasma-spraying conditions. The system has made it possible to collect about 10 single particles successively within a 10 s time frame, and to correlate exactly the relationship between the size, the temperature, and the impacting velocity of each droplet, and the morphology of the splats. The most striking finding is that a part of the yttria-stabilized zirconia (YSZ) droplets may be actually in supercooled condition before impinging, although a marked difference was not found in the splat morphology. In addition, as secondary results, we could evaluate the viscosity, It, of YSZ, and the thermal contact resistance between YSZ splat and the quartz glass substrate as mu [Pa (.) s] = 0.0037 exp (6110/T) and 3 x 10(-6)-4 x 1 10(-5) m(2) K/W, respectively.