• Visualizations of the electron-trapping process employed to convert cement to metal.

    Credit: Image courtesy of the Argonne National Laboratory

    Visualizations of the electron-trapping process employed to convert cement to metal.

Medieval alchemists' vain attempts to transform lead into gold have become representative of the limitations of science as a vehicle for the fulfillment of human greed. The alchemists' decisive failure to substitute one substance's properties for another has reinforced the notion of physical boundaries in material composition that cannot be crossed. Yet, recently, scientists have actually been able to achieve alchemical transformations in particular materials—disrupting centuries' worth of preconceptions about material behavior. 

A multinational team of researchers from the U.S., Japan, Finland, and Germany recently announced its successful transformation of cement into metal. Unlike the lead-to-gold conversion, this alchemical process will enable more versatile electronics with the development of cement semiconductors. The new approach will lead to the creation of novel coatings, thin-films, and computer chips. 

Why cement in lieu of metal? According to the research team, cement—or rather the cementitious ingredient mayenite, which comprises calcium and aluminum oxides—exhibits superior properties over both metal and glass conventionally used for these applications. The cement does not corrode like metal, for example; nor does it possess the fragility of glass. Made by a process known as electron-trapping, the material is also easy to mold and is highly conductive. 

"This phenomenon of trapping electrons and turning liquid cement into liquid metal was found recently, but not explained in detail until now," said Argonne National Laboratory physicist Chris Benmore in an ANL press release. "Now that we know the conditions needed to create trapped electrons in materials, we can develop and test other materials to find out if we can make them conduct electricity in this way." 

Although remarkable, this alchemical discovery's environmental implications remain unclear. For example, by trading cement for metal, is one carbon-intensive process simply replacing another? Is it possible to produce a cement-based semiconductor with less energy than metal versions, or is the new method—which requires high-heat and pressure—simply replicating the problems of conventional approaches? We can assume that cement-to-metal alchemy was not invented purely to generate wealth, as was the case with lead-to-gold conversion. However, if significant environmental damage results from a fully industrialized version of the process, it could result in a new tale of scientific folly.

Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.