Encapsulating Alumina Ceramic to 304 Stainless Steel with Filler of Al-Zn-Mg-Cu Powder

Al₂O₃ ceramic and 304 stainless-steel were encapsulated with the lab-made filler of Al-Zn-Mg-Cu powder.The influence of the sintering temperature and time on the phases and shear-strength of the encapsulated seam was investigated with X-ray diffraction, energy dispersive spectroscopy, scanning electron microscopy.The results show that the sintering temperature and time had a major impact.For example, the shear-strengths decreased with an increase of sintering temperature, and changed in an increase-decrease mode with an increase of sintering time, as both the sintering temperature and time increased, the shear-strengths increased up to 11.4 MPa.Sintered at 570℃ for 1 h, fairly compact Al-Zn-Mg-Cu alloy formed, comprising α-Al, MgZn₂, Fe-Al and MgAl₂O₄phases;and the shear-strengths on the stainless-steel and Al₂O₃ sides were 24 MPa and 6.4 MPa, respectively.Formation of MgAl₂O₄possibly accounted for the improved wettability of Al-alloy and Al₂O₃ ceramic.