Microstructure and Properties of Pack Cementation Sili-conized Layer on AISI-304 Stainless Steel

Fine and compact siliconized layer was prepared on the surface of AISI-304 stainless steel via pack cementation siliconiz-ing of mixed Si-Fe alloy powder with 70% Si (mass fraction) in the presence of SiO2 as a loosening agent. The microstructure of the siliconized layer was analyzed by means of scanning electron microscopy and X - ray energy dispersive spectrometry. Besides, the microhardness of the siliconized layer was measured, and its adhesion to substrate was evaluated by conducting notched break-ing test. Results indicate that the siliconized layer has a thickness of over 50 μm and shows typical columnar crystal structure. The Si concentration of the siliconized layer was ranged within 12.24% ～20. 93% from the inner zone to the surface, and the corresponding microstructure assumed gradient distribution from the surface to the inner zone, while nanocrystal structure appeard at the interface. At the same time, the siliconized layer had a micro-hardness of 406 ～ 477 HV1N from the inner zone to the surface, and was well bonded with the steel substrate.