Catalysis of Rare Earth Element Nd on Bonding of AIS11045 Steel

摘要

The present study evaluate the catalysis of Nd_2O_3 on the bonding of AISI 1045 steel using a 5% Nd_2O_3-containing bonding agent in a temperature range of 1 213 K to 1 350 K for 2 h-5 h. The morphology and types of borides formed on the steel surface were confirmed by optical microstructure, scanning electron microscopy and X-ray diffraction. The results show that the Nd_2O_3 has contrary effects on boriding process, i.e. promotion at high temperatures or hindrance at low temperatures. Nd_2O_3 addition can significantly reduce the activation energy of boride growth at high temperatures, decreased it from 198 kJ/mol to 137 kJ/mol, reduced by 31% in the high temperature range of 1 133 K-1 213 K as compared with that without Nd_2O_3 addition. The catalysis mechanism of RE element Nd during boriding process was discussed through the analysis of chemical reactions probably occurred in boriding agent, changes in surface morphology and chemical composition.