Kauffmann, F.; Ji, B.; Dehm, G.; Gao, H.; Arzt, E.: A quantitative study of the hardness in a superhard nanocrystalline titanium nitride/silicon nitride coating. Scripta Materialia 52 (12), pp. 1269 - 1274 (2005)
If manganese nodules can be mined in an environmentally friendly way, the critical metals needed for the energy transition could be produced with low CO2 emissions