窒化珪素セラミックス/ステンレス鋼接合体の破断強度に及ぼすセラミックス強度とNi中間材厚さの影響

抄録

Fracture strength of Si₃N₄ ceramics joined to stainless steels with a Ag-Cu-Ti filler and a Ni(0.02∼0.5 mm)/W/Ni interlayer was investigated as functions of the ceramic strength and Ni-interlayer thickness.
For the joints with a 1500 MPa ceramics fracture strength of the joints increased monotonously with decrease of Ni-interlayer thickness from 300 MPa at 0.5 mm to 660 MPa at 0.02 mm. For the joints with 800 and 1100 MPa ceramics, however, the fracture strength decreased rapidly when the Ni-interlayer was thinner than 0.25 mm. This degradation seems to be due to cracks formed during a bonding process. The effect of ceramic strength on the fracture strength of ceramic/metal joints was hardly observed when these pre-cracks were eliminated from the joints.
It was suggested that the bonding layer plays decisive role in the fracture strength of ceramic/metal joints in addition to the thermal residual stress, irrespective of the ceramic strength itself.