DYNAMICS OF BRAZE SPREADING

Fundamental studies of liquid flow provide a useful framework for analysing the spreading behaviour of brazes. Three stages can be distinguished by analysing kinetic data for the spreading of a reactive Ni-P braze over Fe-Cr workpieces. The first and last stages when the interfacial microstructure is relatively stable can be modelled by mathematical relationships developed to describe the flow of idealised non-reactive systems, while the intermediate stage can be related to the flow kinetics of active metal brazes over ceramics. We discuss the mechanisms responsible and argue that classification of kinetic behaviour could be of value in modelling other systems.