Chemical interaction between a sialon cutting tool and iron-based alloys

Sialon ceramics have been recently introduced for machining cast iron at very high speeds. However, they have been found to be unsuitable for machining steels. One of the factors influencing this difference in behaviour is thought to be chemical dissolution of the ceramic in the chip at the high temperatures reached at the cutting edge. Based on static interaction couple experiments in vacuum, the chemical interaction between a sialon ceramic and a number of steels as well as grey cast iron was studied in the temperature range 1000-1200 degrees C. The solid state interaction with grey cast iron was found to be less than with steels. The influence of alloying elements present in the steel on the chemical compatibility with sialon ceramics could be attributed directly to their effect on the nitrogen solubility in steel. Based on the results of chemical interaction, a dissociation mechanism of sialon ceramic in contact with iron-based alloys is proposed.status: publishe