| Joining technology of ceramics, have been paid extensive attention on study and applications. It provided a probability to fabricate larger or complex components from basic shaped ceramic bodies with low cost and simple operation. Its significance may match with that of welding technology to metal material.In this work, ceramics joining of sintered bodies containing medium layers were concerned. For joining of sintered Al2O3 and YSZ ceramics, the interlayer components, containing Al2O3, YSZ and SiC, was designed according to the Al2O3- ZrO2 -SiO2 system phase diagrams. A series of interlayers were prepared by changing the contents of Al2O3 and SiC. Joining qualities and process conditions, including joining temperature and temperature schedule, thickness and composition of interlayer, crack and pore of interface, as well as component change and reaction during joining process, were investigated by XRD and SEM.The joining mechanism was analyzed, and refered to thermodynamics computation of interfacial reaction, as well based on experiments, the best sintering temperature was determinated as 1500℃. It was showed that a combination of fast sintering and slow sintering could result in the best joining effect; From the result, the interlayer which contained 38wt% Al2O3, 20wt% YSZ and 42wt% (28wt%) SiO2 (SiC) achieved the best joining effect. It was supposed that a sufficient interfacial reaction, suitable expanding by SiC oxiding might take place under that component condition, also that forming of mullite, a main phase resuled by reaction of Al2O3 and oxided SiC, might promote the interfacial contacts by mass transfer duo to its sticky flow at elevating temperature. Based on a series of tests concerning interlayer thickness and joining pressure, it was illustrated that the best joining effect was achieved under conditions with tiny pressure and thiner thickness,namely the interlayer contains 30wt% solid content.
|
PDF Full Text Request