title: Development of graded Ni-YSZ composite coating on Alloy 690 by Pulsed Laser Deposition technique to reduce hazardous metallic nuclear waste inventory.
abstract: Alloy 690 based 'nuclear waste vitrification furnace' components degrade prematurely due to molten glass-alloy interactions at high temperatures and thereby increase the volume of metallic nuclear waste. In order to reduce the waste inventory, compositionally graded Ni-YSZ (Y(2)O(3) stabilized ZrO(2)) composite coating has been developed on Alloy 690 using Pulsed Laser Deposition technique. Five different thin-films starting with Ni80YSZ20 (Ni 80 wt%+YSZ 20 wt%), through Ni60YSZ40 (Ni 60 wt%+YSZ 40 wt%), Ni40YSZ60 (Ni 40 wt%+YSZ 60 wt%), Ni20YSZ80 (Ni 20 wt%+YSZ 80 wt%) and Ni0YSZ100 (Ni 0 wt%+YSZ 100 wt%), were deposited successively on Alloy 690 coupons. Detailed analyses of the thin-films identify them as homogeneous, uniform, pore free and crystalline in nature. A comparative study of coated and uncoated Alloy 690 coupons, exposed to sodium borosilicate melt at 1000°C for 1-6h suggests that the graded composite coating could substantially reduced the chemical interactions between Alloy 690 and borosilicate melt.
authors.affiliation: Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. praneshsengupta@gmail.com
authors.forename: Pranesh
authors.initials: P
authors.lastname: Sengupta
authors.forename: Detlef
authors.initials: D
authors.lastname: Rogalla
authors.forename: Hans Werner
authors.initials: HW
authors.lastname: Becker
authors.forename: Gautam Kumar
authors.initials: GK
authors.lastname: Dey
authors.forename: Sumit
authors.initials: S
authors.lastname: Chakraborty
mesh_terms: D015386:Hazardous Substances; D009532:Nickel / Q000737:chemistry*; D011850:Radioactive Waste; D015019:Yttrium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D015386:Hazardous Substances; D011850:Radioactive Waste; D015019:Yttrium; D009532:Nickel; D015040:Zirconium; C028541:zirconium oxide