In decommissioned aircraft, high-value components containing precious metals—such as ruthenium, iridium, platinum, palladium, and rhodium—are primarily concentrated within the engines, specifically in the turbine blades, combustion chambers, and catalytic converter assemblies. Since these components operate in environments characterized by extreme heat and high pressure, platinum group metals are essential for enhancing their heat resistance and structural stability.
1. Engine Turbine Blades
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Location: High-pressure turbine and low-pressure turbine blades.
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Manufactured using nickel-based superalloys, with internal additives of iridium (Ir), platinum (Pt), and ruthenium (Ru) to enhance creep resistance and oxidation resistance.
2. Combustion Chambers and Turbine Disks
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Location: Combustion chamber liners and turbine disk rims.
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Platinum is utilized in high-temperature protective coatings to prevent oxidation and corrosion.
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Palladium (Pd) and Rhodium (Rh) are frequently employed in heat-resistant components within high-temperature sensors and electronic control systems.
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Rhodium is also incorporated into certain high-performance alloys to enhance their strength and corrosion resistance.
3. Avionics and Sensors
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Location: Flight control modules, temperature/pressure sensors.
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Utilize palladium-containing ceramic capacitors, gold-plated circuit boards, and high-temperature solders.
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Certain precision sensors employ platinum wire as the temperature-sensing element.
4. Catalytic Converters
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Applicable Aircraft Models: Some business jets or specially modified aircraft are equipped with emission control systems similar to those found in automobiles.
5. Other Potential Sources
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Thermal Insulation Materials and Coatings: The external thermal insulation layers of engines may contain platinum group metal powders acting as stabilizers.
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Solder Joints and Connectors: Utilize specialized solders containing gold, palladium, and platinum to prevent failure under high-temperature conditions.