EROSION PLUME DYNAMICS DURING PULSED-LASER ALLOYING

Dynamics of erosion plume during pulsed laser alloying (lambda = 1.06 mu m, pulse duration in millisecond range, power density 10(5)-10(6) W /cm(2)) of Fe with Mo, Al, Sn was analysed by means of high speed phot orecording. Two qualitatively different types of plume dynamics were f ound: cylindrical vapour helixes and periodic pulsation. The monitorin g of plume dynamics and melt ejection allows one to prevent destructio n of the treated surface, to decrease the loss of doping element and t o reach its uniform distribution (system: Cr shielding coating-Sn coat ing-Fe substrate).