Study the sintering behavior of nanocrystalline 3Y-TZP/430L stainless-steel composite layers for co-powder injection molding

摘要

Recently, co-powder injection molding process (2C-PIM) has attained considerable interest to fabricate complex-shaped functional materials. The aim of this work is to study the sintering compatibility between nanocrys_talline yttria-stabilized zirconia (3Y-TZP) and PIM grade 430L stainless steel (SS) powders, which is the utmost important step in the 2C-PIM process. To evaluate the mismatch strain development during the co-sintering, the isothermal and nonisothermal behaviors of the ceramic and metal powders were studied. Small bilayers of 3Y-TZP/ 430L were made by a powder metallurgy technique and the feasibility of simultaneous sintering and joining of the composite layer was examined. Electron probe micro-analyzer (EPMA) was used to study the joint interface. The shear strength of the bond was tested by a shear-punch instrument. It is shown that the amount of mismatch sin_tering shrinkage between the zirconia ceramic and SS powder during sintering can be as high as 9.7%. Mean_while, sintering in vacuum induced lower mismatch strain compared to argon sintering. It is also shown that formation of a liquid phase by boron addition to the SS layer could assist bonding. The liquid phase accommodates the mis_match sintering shrinkage and ease materials transfer at the interface. EPMA analysis confirmed the interlayerdiffusion of Zr, Fe, and Cr during sintering to form a ternary Zr_Fe_Cr oxide interface.