Coating of austenitic stainless steel with Ni- Al -Cr intermetallic by self propagating high temperature synthesis (SHS)

SUMMARY COATING OF AUSTENITIC STAINLESS STEEL WITH Ni- Al -Cr INTERMETALLIC BY SELF PROPAGATING HIGH TEMPERATURE SYNTHESIS (SHS) In this thesis, Ni3Al-Cr intermetallic was coated on an austenitic stainless steel by Self Propagating High Temperature Synthesis (SHS) method and following sintering and the effects of process parameters on the microstructure of the coating was investigated. Ni and Al powders of 3:1 in atomic ratio were mixed with Cr in 8 and 10 % in weight and mixed by a mixer connected to a eccentric shaft in different containers at 18 rpm for 24 hours for a homogenous mixture. The mixture then cold compacted in the metal dies with a diameter of 1 mm under 100 and 200 MPa. A thin Nickel layer from Ni powder was placed on the stainless steel substrate and this combination (Ni3Al compact Ni layer and austenitic stainless steel rod) was placed in the reaction chamber. The process was realized by applying a fixing load of 50 N and sintering at 1000 and 1100 C for 45 minutes after ignition completed. The specimens were investigated by optical SEM microscopy and the microstructures occurred were determined by EDS and XRD. In the first chapter of the study, the subject is introduced. In the second chapter a literature research was given on the materials and the method (SHS) itself. In the third chapter, the experimental studies, materials and method were presented. In the fourth chapter the results and in the fifth and last chapter conclusion and recommendations are given. Keywords: SHS; AISI 304,Ni3Al-Cr, coating, intermetallic