Yttrium Aluminium Garnet (YAG) has emerged as a leading topcoat material for next-generation thermal barrier coatings (TBCs), prized for its exceptional high-temperature stability and superior resistance to CMAS (calcium-magnesium-alumino-silicate) attack. CrownRe, a pioneer in advanced coating solutions, has successfully deposited high-performance YAG topcoats using both suspension and solution precursor high-velocity oxy-fuel (HVOF) thermal spray technologies.

Through comprehensive characterization and rigorous thermal cycling tests, CrownRe has established clear correlations between spray processes, coating microstructure, and performance outcomes. The YAG coating derived from stoichiometric solution precursor (SP-YAG) exhibits a uniform distribution of pores and inter-splat boundaries in its as-sprayed state. In contrast, coatings produced from suspension (S-YAG) display characteristic vertical and branched micro-cracks, alongside pores and inter-splat boundaries. Both as-sprayed coatings consist of an amorphous phase combined with hexagonal yttrium aluminium perovskite (YAP) and cubic YAG crystalline structures.

In thermal cycling tests simulating extreme operational environments, CrownRe’s S-YAG coatings demonstrated outstanding durability, meeting the failure threshold only between the 60th and 70th cycles. Meanwhile, the SP-YAG coating showed earlier failure, reaching the 20% mark by the 10th cycle. Analysis confirms that failure in both coating types resulted from accumulated thermal stresses during repeated cycling—highlighting the critical role of microstructure in extending service life.

CrownRe’s innovative YAG TBC solutions offer enhanced performance and extended lifespan for high-temperature components, reinforcing our commitment to delivering materials that excel under the most demanding conditions.