PREPERATION AND STRUCTURE OF PALLADIUM-MODIFIED ALUMINIDE COATINGS
钯改性铝化物涂层的工艺及组织

The plating bath with Pd(NH3)zC1z and the related process for electdeposition of palladium and palladium-nickel alloys were described, which were pre-applied for prepexation of Pd-dified aluminide coatings on the cast nickel-base superalloy M38 by pack cementation. EM, XRn and SEM were adopted to characterize the distribution of elements, the phase constituent and mrpholcgy of cross section of the Pd- ified aluminide coatings respectively in detail. A major difference with Pt-dified aluminide coatings may amibute to that the Pd containing zone was a single phase of the known P-(Pd,Ni,.,) Al. The aluminum concentration remained constant (55at % -60at % ) acnxss the outer layer of coating and balanced with the total concentration of palladium and nickel, in spite of a negative palladium concentration gradient.