Most QR codes are currently found on products and advertisements, often as stickers, but for this project Jeroen de Vries and his colleagues at the Netherlands’ University of Twente are etching the codes onto a tungsten disc covered in a protective layer of silicon nitride, so that the information will stay readable for millions of years.
Tungsten was used for its ability to withstand high temperatures and its low thermal expansion coefficient, and silicon nitride is transparent, resistant to cracks, and can tolerate extreme heat without expanding. Together, the material survived tests with heats of 200 degrees Celsius.
Previous civilisation have saved their thoughts and ideas with writing on cave walls or bricks, but in our digital society we can now save some of our ideas for future generations with the use of a clever material and a quick response code.