Preparation And Thermosensitivity Of MXenes Modified Rare Earth Doped Temperature-Sensitive Thermal Barrier Coatings Materials

The fluorescence intensity of rare earth elements doped in temperature-sensitive thermal barrier coatings（TBCs）decreases rapidly due to the interactions of multiple components within TBCs.And high temperature service environment reduces the temperature sensitivity of rare earth elements.Meanwhile,the fluorescence lifetime decays in long-term service coatings.To solve above problems,8YSZ:Eu³⁺,MXene and N-MXene is prepared by chemical co-precipitation,chemical etching and hydrothermal reaction method,respectively.Furthermore,MXene/8YSZ:Eu³⁺and N-MXene/8YSZ:Eu³⁺temperature-sensitive TBCs materials are synthesized by mechanical grinding.The effects of MXene and N-MXene on the phase structure,surface morphology,fluorescence properties and temperature-sensitive properties of8YSZ:Eu³⁺ceramic materials are systematically investigated.The main findings are summarized as follows.（1）The 8YSZ:Eu³⁺ceramic material prepared by chemical co-precipitation method is a stable crystal structure of tetragonal phase.Eu³⁺and Y³⁺is completely solidly dissolved in the Zr O₂ lattice,while Eu³⁺occupies the inversion center of the Zr O₂ lattice,and the Y₂O₃ content is 8.28 mol%.8YSZ:Eu³⁺ceramic material is spherical or ellipsoidal with a particle size of 20 nm.The fluorescence results demonstrate that 8YSZ:Eu³⁺materials have good fluorescence and temperature-sensitive properties.Under the given conditions in this paper（excited at 250 nm）,the strongest fluorescence intensity locates at 591 nm and 605 nm,corresponding to the transition of ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂ for Eu³⁺ions,respectively.The fluorescence lifetime of 8YSZ:Eu³⁺material is 1.36 ms at room temperature.The absolute and relative sensitivities of 8YSZ:Eu³⁺material is 0.54%K^-1@350 K and 0.53%K^-1@350K,respectively.（2）The accordion-shaped Ti₃C₂ MXene with-OH,-F and-O functional groups is successfully prepared by HF etching.And the MXene/8YSZ:Eu³⁺temperature-sensitive TBCs materials are further synthesized by mechanical grinding.The8YSZ:Eu³⁺ceramic material maintains in the stable tetragonal phase structure.Part of the 8YSZ:Eu³⁺ceramic particles wrap up the accordion-shaped MXene,while the other embed in the middle of MXene sheet,resulting in a greater improvement on the fluorescence and temperature-sensitive properties of MXene/8YSZ:Eu³⁺materials.The MXene/8YSZ:Eu³⁺TBCs material containing 6 wt%MXene achieves the best fluorescence and temperature-sensitive properties,which maximum fluorescence intensity is approximately 3 times of 8YSZ:Eu³⁺.Meanwhile the fluorescence lifetime of MXene/8YSZ:Eu³⁺reaches 1.41 ms.The absolute and relative sensitivities are S_A（Y/M-6）=1.20%K^-1@350 K and S_R（Y/M-6）=1.14%K^-1@350 K,respectively,which are both nearly 2 times of 8YSZ:Eu³⁺.（3）Ti₃C₂ MXene is modified to get-N functional group by hydrothermal reaction,and the N-MXene/8YSZ:Eu³⁺temperature-sensitive TBCs materials are synthesized by mechanical grinding subsequently.The results indicate that the 8YSZ:Eu³⁺ceramic material remains as a stable tetragonal phase structure.The 8YSZ:Eu³⁺particles is successfully embedded in the folded structure and interlayer of N-MXene material,leading to a much better fluorescence characteristics than 8YSZ:Eu³⁺material.Also the fluorescence and temperature-sensitive of N-MXene/8YSZ:Eu³⁺are better than MXene/8YSZ:Eu³⁺.The N-MXene/8YSZ:Eu³⁺material containing 0.6 wt%N-MXene obtains the best fluorescence intensity and lifetime,which fluorescence lifetime extends1.44 ms at room temperature.The introduction of N-MXene modified the temperature-sensitive properties of Eu³⁺,that is to say,the fluorescence intensity of the N-MXene/8YSZ:Eu³⁺materials increase as temperature increases.The absolute and relative sensitivity of N-MXene/8YSZ:Eu³⁺materials are S_A（Y/NM-6）=1.41%K^-1@350 K and S_R（Y/NM-6）=1.16%K^-1@350 K,respectively,which are both higher than that of 8YSZ:Eu³⁺material.