Active metal brazing of silicon nitride ceramics using a Cu-based alloy and refractory metal interlayers. Issue 4 (March 2016)

• Record Type: Journal Article
• Authors: Fernandez, J. Martinez; Asthana, R.; Singh, M.; Valera, F.M.
• Is Part Of: Ceramics international. Volume 42:Issue 4(2016)
• Page Start: 5447
• Page End: 5454
• Publication Date: 2016-03
• Subjects: Silicon nitride -- Active metal brazing -- Multilayer joints -- Shear strength -- Scanning electron microscopy; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2015.12.087
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Silicon nitride/silicon nitride joints with refractory metal (W and Mo) interlayers were vacuum brazed using an active braze, Cu-ABA (Cu–3Si–2Al–2.25Ti, wt%), and two interlayer arrangements in a double-lap offset configuration: Si3 N4 /Cu-ABA/W/Cu-ABA/Mo/Cu-ABA/Si3 N4 and Si3 N4 /Cu-ABA /Si3 N4 . Titanium segregated at the Si3 N4 /Cu-ABA and Mo/Cu-ABA interfaces, but not at the W/Cu-ABA interface. The room-temperature compression-shear strength values of Si3 N4 /Cu-ABA/Si3 N4 and Si3 N4 /Cu-ABA/W/Cu-ABA/Mo/Cu-ABA/Si3 N4 joints were 118±24 MPa and 22±5 MPa, respectively. Elevated-temperature compression tests showed that Si3 N4 /Cu-ABA/Si3 N4 joints had strength of 31±6 MPa at 1023 K and 17±3 MPa at 1073 K. Likewise, Si3 N4 /Cu-ABA/W/Cu-ABA/Mo/Cu-ABA/Si3 N4 joints had strength of 19±4 MPa at 1023 K and 13±3 MPa at 1073 K. Knoop microhardness profiles revealed hardness gradients across the joints. The effect of joint microstructure and test configuration on the mechanical behavior is discussed.