On the influence of spraying conditions and powder feed structure on wear properties of atmospheric and vacuum plasma sprayed Al_2O_3-13TiO_2 coatings

摘要

Mechanical and wear properties of APS and VPS sprayed Al_2O_3-13wt%TiO_2 coatings from microstruc-tured and nanostructured powders were investigated. It was found that: 1. VPS applied coating performance and characteristics, such as abrasion wear resistance, adhesion/cohesion strength, microhardness, are generally superior than those of APS applied coatings. 2. Powder feed structure (micro or nanostructured) can significantly influence the resulting coating characteristics. Nanostructured powders are found to be more sensitive to the thermal spray process compared to conventional microstructured powders. 3. Powder fabrication process plays a major role in the resulting coating performance. Indeed, the two nanostructured powders studied in this work (TA100-SD and 2613PA) were fabricated from the same precursor materials (nano alumina and nano titania). However, the resulting coating characteristics were significantly different. 4. In the current study, the VPS applied coating from Inframat nanostructured 2613PA powder sprayed onto a cold substrate was found to be the best performing Al_2O_3-13wt%TiO_2 coating. The superior properties seem to be associated with coatings that have retained nanostructure, especially with partial melting of the nanostructured powders. 5. More work has to be carried out in order to establish the influence of the CeO_2 and ZrO_2 content and of the bi-modal structure found in the coating from the nanostructured 2613PA powder.