1986 Volume 50 Issue 8 Pages 752-757
The joining of magnesia to nickel metal at the temperatures from 1473 to 1673 K has been studied. The technique is an application of the diffusion phenomenon which occurs between magnesia and nickel oxide. Preliminarily, the specimen surface of nickel was oxidized at 1673 K for 0.9 ks in air. Then, a block of magnesia was placed on the preoxidized nickel and was reacted with nickel oxide at the experimental temperatures for 3.6 to 144 ks. Because magnesia and nickel oxide are completely soluble each other, the reaction layers of the joining parts are made of solid solution of these oxides.
The advantageous of this method is that the joining can be accomplished under atmospheric pressure without the use of fillers.
The fracture strength of the joining parts was measured by three point bending tests. The average values of fracture strength ranged from 30 to 40 MPa. The micro-structures of the diffusion layers and fracture surfaces were observed by EPMA, SEM and EDX.
