| Al₂O₃has been joined to STS304 stainless steel by a brazing method using Al-10 wt% Si insert-metal. The joining has been performed in a vacuum hot press under 4 mPa vacuum varying the conditions such as temperature(850-953 K), holding time(0-3.6 ksec) and applied contact pressure(0-9. 8 ㎫). With use of SEM, EDX and XRD observation of the morphology and microstructure for a bonded interface and the analyses for existing elements and phases have been carried out to investigate possible reaction(s) at the bonded interfaces. No reaction at the interface between Al₂O₃and insert-metal has occured but a formation of reaction layer between STS304 and insert-metal layer has been observed which is composed of Al, Si, Fe and Cr. The thickness of reaction layer increases with a joining temperature and a holding time. In the insert-metal layer the acicular eutectic Si-phase and the new ternary compound of (Al, Fe, Si) exist in the Al-matrix after the joining. The strength of joined body measured by a tensile test has been varied with the joining conditions. The maximum average strength of 32 ㎫ has been obtained from the joints which were joined at 873 K for 1.8 ksec under a contact pressure of 4. 9 ㎫. |
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