DIFFUSION BONDING AND POST-BOND HEAT TREATMENT OF SIALON TO NITRIDED A lSI 420 STAINLESS STEEL

Sialon and stainless steel are two different classes of materials which have their
own uniqueness. Joining these materials will produce an effective component design
by benefitting the high strength of the steel in supporting the sialon at high service
temperature. Therefore, this research had been conducted to investigate the
potentiality in joining sialon to AlSl 420 stainless steel. Prior to diffusion bonding of
these materials, the steel was nitrided at 1200°( for one and four hours. The bonding
process was performed at 1200QC under a uniaxial pressure of 17 MPa in a vacuum
for one, two, and three hours. Increasing the bonding time produced thicker reaction
layer The thinnest layer was formed in joining sial on to four hour nitrided steel. From
EDX, XRD, and Raman analysis, no indication pointed to the presence of FeSi in the
joint of sialon-nitrided steels. There was no crack observed in all diffusion bonded
samples However, the diffusion layer and the steel were segregated.