Lanthanide Oxide Stabilized Zirconia Coatings for Phase Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermal barrier coatings (TBCs) based on yttria-stabilized zirconia (YSZ) undergo phase transformation from tetragonal to monoclinic phase upon exposure to high temperatures, leading to volume expansion and cracking, which limits their useful life-time in high-temperature applications.
Innovation Solution
A multi-functional material composition comprising yttria (Y2O3) partially-stabilized zirconia with a luminescent tri-valent lanthanide oxide additive, such as dysprosia (Dy2O3), which stabilizes the zirconia and provides luminescent temperature sensing, allowing for in situ monitoring of the monoclinic phase proportion and extending the useful life-time by delaying and reducing the monoclinic phase formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If yttria-stabilized zirconia is used as TBC material, then the coating provides thermal barrier protection, but the tetragonal phase transforms to monoclinic phase at high temperatures causing volume expansion and cracking
Solution Approach 1:
The patent changes the stabilizing parameter from pure yttria to a combination of yttria and rare earth oxides (lanthanum, cerium, praseodymium, neodymium, or promethium). This compositional parameter change prevents the tetragonal-to-monoclinic phase transformation by maintaining the stabilizing effect at high temperatures, thereby preserving phase stability while withstanding high-temperature exposure.
Solution Approach 2:
The patent creates a composite stabilizing system by combining yttria with rare earth oxides in specific weight ratios (1-20 wt% rare earth oxide with 80-99 wt% yttria). This composite approach leverages the synergistic effects of both stabilizers to maintain tetragonal phase stability at high temperatures, preventing the harmful phase transformation that occurs with pure yttria stabilization.
2Measurement precision
If luminescent materials are added to TBCs for temperature sensing, then in-situ optical measurement is enabled, but the material composition becomes more complex
Solution Approach 1:
The patent achieves multi-functionality by having the rare earth oxides serve dual purposes: (1) as phase stabilizers preventing tetragonal-to-monoclinic transformation, and (2) as luminescent temperature sensors. This eliminates the need for separate additive materials, reducing overall composition complexity while enabling both structural stability and temperature sensing functions within the same material system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition exhibits improved long-term phase stability and enables accurate determination of the monoclinic phase proportion and remaining useful life-time through luminescent emission line intensity ratios, independent of the lanthanide oxide additive concentration, thereby enhancing the durability of TBCs in high-temperature environments.
Implementation Method 1
the lanthanide oxide additive is effective both in stabilizing the zirconia and providing for luminescent temperature sensing
Implementation Method 2
providing for luminescent temperature sensing
Implementation Method 3
utilization of a ratio of the luminescence intensities for emission lines in determining phase concentrations
Data Source
AI summary
A multi-functional material composition comprising a zirconia host and containing a luminescent lanthanide oxide additive, in particular dysprosia (Dy2O3), wherein the lanthanide oxide additive is effective both in stabilizing the zirconia and providing for luminescent temperature sensing, and a method of determining a remaining useful life-time for the luminescent material composition from the proportion of a monoclinic phase (m) in the material composition.