|
5477 |
|
Improved sprayability on thermal spray coatings with different powder feeders |
|
Francesco Bozza* / Turbocoating S.p.a., Italy Nelso Antolotti / Turbocoating S.p.a., Italy Luca Tagliaferri/ Turbocoating S.p.a., Italy Simone Bursich/ Turbocoating S.p.a., Italy Enea Ghidini/ Turbocoating S.p.a., Italy Luigi Coppelletti/ Artec S.p.a., Italy |
|
Thermal spray coatings have been established as one of the most widely used technique for applying thick coatings with high deposition rates if compared with other technologies for coatings application. Different type of materials could be applied with Thermal spray techniques (metals, ceramics, polymers and composites) by injecting them in wire or powder form into an high power source able to melt and propel them toward the substrate to be coated. Thermal spray processes are employed in many different fields of applications such as corrosion and oxidation protection, thermal insulation, wear control, medical implants and many others. Powder feedstock are the most widely used media for thermal spray applications, the coating is built up by accumulating splats of molten particles which are injected inside a high temperature plume and propelled toward the substrate. Among all the different thermal spray variables, the powder injection parameter has to be monitored in a very precise way in order to obtain the proper microstructure and as a consequence, the best performances. The aim of the present work was to spray different type of powders with both Air Plasma Spray and High Velocity Oxigen Fuel (HVOF) techniques comparing two different powder feeders. One conventional powder feeder and the new generation volumetric powder feeders. The latter equipment was in fact able to control the powder mass flow in a more precise way, enabling also the stabilization of the thermal spray plume and coating quality for a long period of time with also less maintenance requested. Operating with this new type of powder feeder brought an increase of productivity, less costs for powder waste and equipment consumables due to the more stable injection. |