Effects of binder and thermal debinding parameters on residual carbon in injection moulding of Nd(Fe,Co)B powder

Thermal debinding properties of several organic binders for the injection m oulding of Nd(Fe,Co)B powder have been investigated. The investigation incl uded analysis of the residual carbon content, which affects the magnetic pr operties of the sintered magnet. The effect of several debinding parameters such as specimen thickness, debinding atmosphere, gas flowrate, heating ra te, and debinding temperature were also studied. Depending on the pyrolysis mechanism, binders gave specific results for the residual carbon. The mole cular weight was found to have a large effect on the residual carbon and sh owed a logarithmic linear increase with increase in residual carbon. Hydrog en gas was found to be the most appropriate atmosphere for the debinding of the moulded specimens. Slow heating and high temperature were found to be effective for low residual carbon. Gas flowrate showed little effect and sp ecimen thickness showed no effect, except with stearic acid.