Effect of Nb and Cu metal layer thickness on microstructure and property of Si₃N₄/Nb/Cu/Ni/Inconel600 joint

Partial liquid phase diffusion bonding (PLPDB) of Si₃N₄ to Inconel600 high temperature alloy was carried out by using the interlayer of Nb/Cu/Ni foil. The main processing factors had been highlighted for the strength of Si₃N₄/Nb/Cu/Ni/Inconel600 system. Optimum parameters had been obtained as bonding temperature 1403K,bonding time 50 min and bonding pressure 7.5 MPa. Effects of Cu and Nb metal layer on the microstructure and properties of joint were respectively investigated by changed thickness of Nb and Cu layer. Test results showed that while the thickness of Cu layer was thinner than 0.05 mm, the strength of joint increased fast with the increase of Cu layer thickness; but when the thickness surpassed 0.05 mm, the strength of joint increased slowly with the increase of Cu layer. When the thickness of Nb layer increased,the thickness of reaction layer increased, but the strength of Si₃N₄/Nb/Cu/Ni/Inconel600 joint increased firstly to a maximum value,then decreased.