Scientists from the University of Maryland recently published a paper explaining how they can make wooden products at least as tough as steel. This “Hardened Wood” (HW) could be a cheaper, more renewable alternative to steel.
The article first appeared last week in an issue of the science journal “Matter.” The original article is behind a paywall but Oddity Central and a couple YouTube videos summarize the main points. The researchers demonstrate their method with two examples: a wooden knife they say is three times shaper than a steel knife and cuts through steak just as well, and a rust-proof wooden nail that can be easily hammered through three solid boards.
The process works by removing certain elements from the wood through chemical treatment, and then increasing its density. The researchers say this can increase the wood’s hardness by 23 times.
The study’s author, Teng Li, says wood is mainly made of cellulose, which actually has a higher strength-to-density ratio than things like ceramics, metals, or polymers. The problem, according to Li, is that the cellulose only makes up about half of wood, the rest being the weaker components hemicellulose and lignin.
The process of making HW involves removing the weaker elements, like lignin (which is called delignification), then applying pressure to remove any water density. After this, the wood can be carved and polished into any shape. It can also be treated with mineral oil to reduce water absorption, extending its lifetime.