Discover how PGMs influence the comfort of your next flight
You roll your suitcase into the terminal, boarding pass ready to go, checking your watch to make sure you are on time for your flight, the last thing you need is a chemistry lesson. But from the moment your trip begins, precious metals like platinum, palladium, rhodium, ruthenium and iridium are hard at work behind the scenes to get you to your destination. Platinum group metals (PGMs) make modern air travel convenient, safe and stress free.
“Nothing beats a Jet A holiday”
Before you even see the aircraft, airport workers are filling it with fuel. For decades, that fuel has been Jet A – a kerosene derived from crude oil. In the coming years, sustainable aviation fuels (SAF) will play an important role to help decarbonise this industry.
SAF is produced from non-petroleum feedstocks, such as waste oils, agricultural residues, municipal wastes, used cooking oil and even captured carbon dioxide. These inputs are converted into aviation fuel though several advanced chemical processes such as hydro-processed esters and fatty acids (HEFA), Fischer-Tropsch synthesis or alcohol-to-jet conversion.
Behind many of these processes are precious metals catalyst that help transform raw materials into high quality jet fuel. In some pathways, platinum group metals act as catalyst or catalyst promoters that help control reactions like hydro-isomerisation, which ensures the fuel performs correctly at the extremely low temperatures experienced during flight.
Many of the flagship SAF projects now moving from pilot to demo scale rely on precious‑metal catalysts in key steps. In emerging power-to-liquid pathways, green hydrogen that is produced by electrolysers containing platinum group metals is combined with captured CO2 to generate synthetic jet fuel.
Today, SAF meets less than 0.2% of aviation fuel demand but production is rapidly expanding. By 2030, it could supply 3-4% of global jet fuel demand, a major step towards decarbonising aviation.
Looking ahead, we may see hydrogen-powered aircrafts. Companies like ZeroAvia are developing hydrogen fuel cell propulsion that use proton exchange membranes (PEM) which rely on platinum group metals to generate electricity onboard the aircraft.
Under the wing
As you prepare to board, you can’t help but notice the wing and engines that must endure repeated temperature and pressure swings and stresses. At take-off, the temperature entering the first turbine stage can be higher than the melting point of the metal yet the blades survive countless cycles. This is made possible by advanced nickel-based single-crystal superalloys, engineered to retain strength under extreme centrifugal forces and heat. Even so, these materials cannot endure the environment unaided. Platinum-aluminide bond coatings are applied to protect turbine blades from oxidation and corrosion and also help anchor the ceramic thermal barrier coating that insulates the underlying metal from the hottest gases.
During casting of the single-crystal turbine blade, fine platinum pinning wires are used to hold the ceramic cores that form the blade’s internal cooling channels. These wires must withstand extreme temperatures and then dissolve cleanly into the alloy without affecting its properties. While palladium-based alternatives have been explored, platinum remains the traditional and widely used material for this purpose.Cabin and comfort: clean air, quiet chemistry
Once you step through the aircraft door, you don’t notice the previous passengers who sat there for the past 8 hours or taste ozone from the stratosphere due to the help of precious metal catalysts.
The cabin air systems continually mix fresh, high-altitude air with recirculated cabin air. At high altitudes, ozone concentrations in the air can be elevated and harmful if inhaled. Precious metal-containing catalyst can also remove the odorous volatile organic compounds (VOC) which can originate from engine oils, fuel residues, keeping the cabin smelling pleasant.
“This is your captain speaking…”
The pilot has a lot to do but he is helped by precious metals.
Igniters for the combustor can use precious‑metal tips (including platinum or iridium) to withstand repeated high‑energy sparks in a hot, chemically aggressive environment. Without reliable ignition, there is no take‑off.
The pilot is surrounded by gauges to tell him all the information about the engines. Platinum-based resistance temperature detectors (RTDs) and platinum- rhodium thermocouples are widely used to measure extreme engine temperatures.
Oxygen sensors containing platinum catalysts help monitor the fuel-to-air ratio so the engine burns fuel efficiently.
Put your phone in flight mode
To ensure reliable electrical performance, many aerospace electronics use precious metal finishes that not only use gold and silver but also palladium to help improve the signal. These metal finishes appear on contact surfaces, connector pins and radio-frequency components to help maintain low electrical resistance, prevent corrosion and ensure stable signals in the harsh environment of flight. Palladium is good for wear resistance of the contacts.
Now sit back and relax while you jet off to foreign lands safe in the knowledge that precious metals have got you there.