Characterization of microstructure and mechanical properties of Cr/CoAlY coating and 8% wt. Y ₂ O ₃ -Zr ₂ O ₃ Ceramic Top Coating upon deposition on a superni-718 substrate

The multilayer coatings of (Chromium/ Cobalt Aluminium Yttrium (CoAlY) and 8% wt Y 2 O 3 -Zr 2 O 3 (Yttria-stabilized Zirconia) Ceramic Top Coating were deposited on superni-718 by DC/RF Magnetron Sputtering method. The mechanical and microstructure characterizations of (Chromium/ Cobalt Aluminium Yttrium (CoAlY) and 8% wt Y 2 O 3 -Zr 2 O 3 (Yttria-stabilized Zirconia) Ceramic Top Coating were studied in the present research work. The structural properties of (Chromium/ Cobalt Aluminium Yttrium (CoAlY) and 8% wt Y 2 O 3 -Zr 2 O 3 (Yttria-stabilized Zirconia) Ceramic Top Coating were characterized by X-ray diffraction (XRD) while their microstructure was examined via Field scanning electron microscope (FE-SEM) and chemical composition of (Chromium/ Cobalt Aluminium Yttrium (CoAlY) and 8% wt Y 2 O 3 -Zr 2 O 3 (Yttria-stabilized Zirconia) Ceramic Top Coating was characterized by Energy Dispersive X-ray Spectroscopy (EDS), Atomic force microscope (AFM) were used to analyse the depth of indent. Mechanical properties of (Chromium/ Cobalt Aluminium Yttrium (CoAlY) and 8% wt Y 2 O 3 -Zr 2 O 3 (Yttria-stabilized Zirconia) Ceramic Top Coating were studied by Nano indentation. The modulus of elasticity for (Chromium/ Cobalt Aluminium Yttrium (CoAlY) and 8% wt Y 2 O 3 -Zr 2 O 3 (Yttria-stabilized Zirconia) Ceramic Top Coating was calculated using Oliver and Pharr Model on different loads ranging from 200µN-1000µN.The Nano indentation results revealed that hardness ranging from 3 to 7 GPa was attained on different applied loads among which Chromium coatings exhibited the highest hardness with 38% percent increase in value of hardness on each load as well maximum modulus of elasticity ranging from (512 GPa to 147.3 GPa), indicating high stiffness however better hardness indicates strong adhesion and improved surface strength.