Surface Zn-alloying modification was used to treat pure magnesium,and the effect of diffusion temperature and time on the alloyed microstructure,phase structure and the continuity of alloyed layers was studied as well.The results show that there is a reasonable range of the diffusion temperature to form the continual intermetallic compound layer.On the condition that the diffusion temperature is too low,the diffusion rate is also rather slow because there is no activated Zn atoms generated.Conversely,although high diffusion temperature is beneficial for the formation of alloyed layers,the base metal granular may become coarse then,even the whole base may get changed.Furthermore,excessively high temperature is harmful to the stability of the reacted layers(intermetallic compound).The prolongation of diffusion time may accelerate the flow of Zn atoms and therefore the formation of intermetallic compound,and weaken the preponderance of grain boundary,resulting in the uniformity of solution area and reacted area.In order to obtain the continual reacted area,the diffusion temperature has to be controlled within 400 420 and the corresponding diffusion time has to be over 8 h.