On a silicon wafer the size of a dinner plate, you can place not just one substance but an entire map of thousands of different compositions. A laser knocks atoms off targets and deposits them in thin layers, varying the proportions from point to point. The result is a materials library: more of one metal here, more of another there, and all combinations visible at once.
But at room temperature, many properties remain hidden. A material might fall apart or, conversely, become stronger only when heated. In the past, such maps were rarely heated: there were no suitable furnaces that could heat the entire wafer evenly while allowing the surrounding gas to be changed. The new furnace solves this problem. It has a transparent dome under which you can create an atmosphere of nitrogen or pure oxygen, while controlling the temperature from outside.
At the SOLEIL synchrotron in France, they tested how the crystal lattice of the compositions changes upon heating. X-rays probed each point on the map, and from the shift in peaks they calculated how much the material expands. For simple mixtures, a rule called Vegard's law works: expansion can be predicted from the fractions of components. But for complex compositions, where atoms of different metals are mixed in disorder, this rule fails. The material expands differently than expected.
Such a furnace paves the way for rapid discovery of materials that withstand temperature swings without cracking — for example, coatings for turbines or parts for spacecraft.
A silicon wafer 100 mm in diameter can hold more than 10,000 different compositions if the proportions are varied by just fractions of a percent.