The advantages of YSZ powder 11-125um for thermal barrier coating of engine blades
When yttrium stabilized zirconia powder (YSZ powder, usually 8% Y₂O₃-ZrO₂) is used in thermal barrier coating (TBC) of engine blades in the particle size range of 11-125μm, it has the following significant advantages:
1. Excellent thermal conductivity and thermal insulation performance
– Low thermal conductivity (2.2-2.9 W/m·K): effectively reduce the base metal temperature and extend the life of the blade.
– High thermal expansion coefficient (10-11×10⁻⁶/K): close to the nickel-based high-temperature alloy substrate, reducing the interface stress under thermal cycling.
2. High temperature phase stability
– Tetragonal metastable phase (t’ phase): long-term stability at 1200-1400°C, avoiding volume expansion and coating cracking caused by transformation to monoclinic phase (m phase) during cooling. 8% mol YSZ powder is chemically inert in the hydrocarbon combustion environment of gas turbine engines.
– Yttrium doping effect: Y₂O₃ inhibits phase transformation and improves the reliability of the coating in high temperature service.
3. Good thermal shock resistance
– High fracture toughness: absorb energy through phase transformation toughening mechanism (stress-induced t→m phase transformation) to delay crack propagation.
– Optimized particle size design: 11-125μm powder balances coating density (reduced porosity) and strain tolerance (appropriate porosity to relieve stress).
4. Excellent sintering resistance and chemical stability
– High temperature sintering resistance: coarse particle size (125μm) reduces the specific surface area and inhibits the hardening of the coating caused by excessive grain growth at high temperature (>1200°C).
– Chemical inertness: resists CMAS (calcium magnesium aluminum silicate) corrosion in combustion gas and erosion in oxidizing environments.
5. Process adaptability
– Suitable for plasma spraying (APS) or flame spraying: 11-125μm particle size range ensures powder fluidity and forms a uniform coating (typical thickness 100-500μm).
– High deposition efficiency: coarse particles reduce the proportion of unmelted particles during spraying and improve the bonding strength of the coating.
6. Improved CMAS corrosion resistance
– Large particle structure: Reduce the CMAS melt penetration rate, and doping modification (such as Al₂O₃/Ta₂O₅) can further delay corrosion.
Yttrium-stabilized zirconia (11-125μm) has become the preferred material for TBC of aircraft engine and gas turbine blades due to its high-temperature phase stability, thermal insulation, thermal shock resistance and process friendliness.
