AIC's 46th Annual Meeting

Casehardening is a technique developed to harden the exterior of low carbon content steels for objects such as hand tools or gun parts. Historic descriptions for the process of casehardening are rare. In his 12th century treatise On Divers Arts, Theophilius Presbyter presents one of the earliest, most complete explanations on the process of hardening small files. Traditionally it is thought that carbon is mainly responsible for the hardening of the metal surface, however, a question has arisen on the role of nitrogen in the process. In this experiment, Theophilus’s casehardening method was recreated and the samples produced were analyzed to determine if the method was one of carburization or nitrocarburization. Casehardened samples were analyzed by optical microscopy using a Zeiss Axio Imager. Microstructures of possible nitrides were found in each fired sample though it is not possible to definitively confirm them. While the presence of nitrogen cannot be absolutely confirmed in these casehardened samples, the goatskin used in the recipe was found to be one possible source of nitrogen. Scanning Electron Microscopy (SEM) analysis and Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Spectroscopy were utilized to verify and measure the presence of nitrogen.