The present paper reports on the measurement of coating adhesion with Inconel 718 as a function of substrate temperature in order to qualify the coatings for application in nuclear vitrification furnace. In the present study, the scratch indentation has been used to determine the critical loads and the friction coefficient offered by the coatings as a function of the substrate temperature. It is noticed that as the substrate temperature increases from 673 to 973 K, the critical load also increases from 2.5 N to 6.1 N, while the friction coefficient remains almost constant. Initially at lower loads, nested micro cracks which form in the coating open in the direction of the scratch track. As the scratch length increases with increasing load, the tensile cracking of YSZ gets transformed to conformal cracking. For the coatings deposited at higher temperature, chipping formation gets reduced as a consequence of improved adhesion of the coating with the substrate. This coating with an improved adhesion finds its application as diffusion barrier coating in nuclear vitrification furnace. This will reduce the faster degradation or premature failure of the components of vitrification furnace made up of Ni based super alloy. The use of YSZ diffusion barrier coating increases the durability and efficiency of the component.