Processing Strategies for Tailoring Ceramic-Based Nanostructured Thermal Spray Coatings

New and more demanding applications and higher performance requirements are creating the need for a greater degree of sophistication in engineering coating structures. The use of nanostructured feedstocks provides the possibility of tailoring the structure of thermal spray ceramic-based coatings at the nanoscale. In the present study, it has been found that such an approach can produce coatings with enhanced mechanical, thermal and bioperformance characteristics. It has been shown that the internal structure and external size of agglomerates as well as the spray conditions employed for deposition play a key role in determining the nature and extent of zones of nanostructured material produced in coatings. The characteristics (such as porosity and bonding) of these zones can have an important effect on the coating performance. This approach has been used to tailor Al₂O₃-TiO₂, ZrO₂-Y₂O₃, WC-Co, TiO₂, and hydroxyapatite coatings targeted for use as abradables, for TBCs, against wear and on orthopedic implants.