Abstract
Yttrium aluminum garnet (YAG) is a well-known high-temperature ceramic material that is used in a plethora of applications such as solid-state laser materials, cathode-ray tubes, field emission displays, scintillators, phosphors, electro-luminescent devices, etc. In recent years, plasma-sprayed yttrium aluminum garnet (YAG) has been explored as an alternative ceramic topcoat for thermal barrier coatings (TBCs) as it is known to prevent the oxidation of the bond coat. Also, it possesses high resistance to calcium magnesium aluminosilicate (CMAS) attack compared to conventional yttria-stabilized zirconia (YSZ) TBC topcoat material. In the current investigation, an attempt is made to fabricate plasma-sprayed YAG coating. The flowable powders required for plasma spraying are synthesized by the versatile solution combustion method after optimizing the process with two different fuels. The powders synthesized using hexamine fuel possess blocky angular-shaped particles and very good flowability. The flowability of the powders is correlated to the heat of combustion, adiabatic flame temperature and shape of the particles. The YAG powder synthesized from hexamine fuel is used for plasma spray application as the process results in higher yield and better flowability. The influence of different plasma spray powers (20, 30 and 40 kW) on the phase purity and crystallinity of the YAG coatings is studied using X-ray diffractometry. The influence of three different plasma powers on the microhardness and microstructure of the coatings is explored. The YAG coating plasma-sprayed at 30 kW is relatively a dense coating and exhibits a higher microhardness value of 1342 ± 9 HV at a load of 100 mN. The CMAS resistance of the YAG coatings is also reported.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call