Rudoj Y. Development of graded thermal-barrier coatings and electron beam technology of their deposition on gas turbine blades

Conditions have been determined for deposition on the substrate of a thermal barrier coating with a gradient of composition and structure across the thickness with an outer ceramic layer by electron beam evaporation of a mixture of metals (alloys) and oxides with different vapour pressure at the evaporation temperature in the form of a compressed tablet located at the edge of a ceramic ingot of zirconium dioxide. The thesis presents the results of investigation of the structure and properties of graded thermal barrier metal-ceramic coatings with a transition zone on the basis of Al-ZrO2(Y2O2), Al-Pt-ZrO2(Y2O3) and Al-Y-ZrO2(Y2O3) systems produced by a one-step deposition process. Optimization of the composition of the evaporation tablet enables producing a graded thermal barrier coating with a high thermal cycle fatigue life. A mechanism is considered of formation of gradient structures produced by electron beam evaporation of a composite ceramic ingot based on zirconium dioxide onto high-temperature alloy substrates. The thesis presents the results of investigation of the structure and properties of the recommended gradient thermal barrier coatings of NiCoCrAlY+AlCr/ZrO2(7Y2O3)and MexCy+NiAl/ZrO2(7Y2O3) deposited from the vapour phase by one-step electron beam technology on gas turbine blades.