Joining of hot pressed silicon nitride using three types of stainless steel (AISI 304, 316 and 321) as interlayer was done by diffusion bonding at 1100 degreesC for 120 min. An extensive reaction zone of about 7 mum was formed in the contact region, where Cr2N, FexSiy and alpha-Fe were observed, outside that region the austenitic phase with precipitates of chromium nitride was observed. In the Mo-containing stainless steel (AISI 316) formation of Mo3Si was also detected. Moderate strengths were measured by shear testing for these joints. (C) 2004 Elsevier B.V. All rights reserved.