Comparison of plasma sprayed alumina and zirconia coatings by RF and DC plasma spraying
Low velocity plasma torches allow to spray bigger particles than conventional (CPT) dc plasma torches. For example, with fused and crushed alumina which size distribution is {minus}90 + 45 {micro}m, the deposition efficiency is about 40% with a CPT which nozzle internal diameter (i.d.) is 7 mm against more than 60% when using a 10 mm i.d. torch adapted to work with the same parameters. With the 10 mm i.d. nozzle the particle velocity is only 90 m/s against 130 m/s with the 7 mm i.d. nozzle. RF plasma torches allow to reach even low particle velocities (in the range 20--60 m/s). This paper compares plasma sprayed alumina and zirconia coatings realized with a RF plasma torch, a low velocity CPT and a CPT. Coating characterization (adhesion/cohesion, microhardness, density) are given for two substrate temperatures (75 C and 300 C) and for the three torches. It discusses the influence of particle velocity and substrate temperature on coatings thermomechanical properties.
- OSTI ID:
- 160505
- Report Number(s):
- CONF-940684--; ISBN 0-87170-509-5
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of particle velocity and substrate temperature on alumina and zirconia splat formation
An analytical and experimental study of plasma spraying of alumina: Final program and abstracts