• Patil, Pradeep

Abstract

<jats:title>Abstract</jats:title><jats:p>The present work investigates the hot corrosion behavior of thermally sprayed 65 pct NiCrAlY+ 35 pct TiO2 and 65 pct NiCrAlY+ 30 pct Cr2O3+5 pct YSZ coatings on titanium 15 alloys. The coatings on the titanium 15 alloy substrates exhibit the near-uniform, dense, and adherent microstructure with a porosity of 2.7 to 2.9 %. Thermogravimetric studies are made to examine the hot corrosion performance of coatings in a molten salt environment of Na2SO4+60 %V2O5 at the temperature of 700°C for 50 cycles. One cycle is carried out by heating for a period of one hour and cooling the sample at ambient conditions. The corrosion products are analysed based on scanning electron microscopy, energy dispersive analysis, and X-ray diffraction techniques to study morphology, phase composition, and abundance of the high-temperature corrosion constituents. The bare titanium-15 alloy, 65 pct NiCrAlY + 35 pct TiO2 coating and 65 pct NiCrAlY +35 pct Cr2O3 + 5 pct YSZ coating produced a weight gain of 307.92mg/ cm2, 42.16mg/cm2 and 44.02mg/cm2 respectively after the period of 50 cycles. The effective resistance of the coatings is due to the formation of Ni3V2O8, NiCr2O4, Cr2O3 &amp; AlV2O4 phases.</jats:p>

Topics

• impedance spectroscopy
• morphology
• corrosion
• phase
• scanning electron microscopy
• x-ray diffraction
• composite
• titanium
• titanium alloy
• porosity