The microstructure of siliconized type 310 stainless steel

The siliconization of austenitic type 310 stainless steel was prepared by pack cementation method. The coating is adherent, free of voids and contains ∼5 wt.% Si. Both the coating and the substrate near the coating/substrate interface are turned into layered structure. The substrate remains to be the original face-centered cubic structure but the coating is turned into body-centered cubic (BCC) structure. In the interfacial zone the grain size is reduced to less than 20 nm and high density of dislocations is observed. In the outer zone of the coating the BCC grains are much larger than those in the interfacial zone and contain sub-micrometer precipitates of B2 structure and nanometer Fe3Si precipitates of DO3 structure. Rod-like precipitates of σ phase are also present.