Macroscopic Crack Repairing Of Oxide Ceramics

This paper has launched a series of work to the repairing of the macroscopical crack of ceramic. Here so-called repair is that joining specific ceramic raw materials among the macroscopic crack, which were produced after sintering in ceramic products, then re-sintering in less than matrix sintering temperature, thus macroscopic crack is closed, and does not influence the basic function of use of the original ceramic products.On the basis of consulting documents and a large amount of practice, this experiment adopts the oxide (Al₂O₃ , ZrO₂ ), the carbide (SiC) matches each other for the primitive material with the metal powder (Al powder ), have designed four kinds of different prescription : (1)Al/Al₂O₃/SiC ; (2)Al₂O₃/SiC/ZrO₂; (3)Al/SiC/ZrO₂; (4)Al/Al₂O₃/SiC/ZrO₂. In order to study the sintering performance of each prescription in advance, carry on volume and quality change to each sintering sample of prescription analysis, XRD diffraction phase analysis and SEM micrographs etc.. The result indicates that the synthetic temperature of mullite decreases notably (<1350℃) with the content of Al powder increasing, however sintering performance for the ceramic deteriorates at the same time. The addition of alumina and zirconium makes it easy to sinter, and reduces the sintering temperature, and improves the body performance at the same time.Samples of experiments sinter ordinarily in the air atmosphere, utilizing metal and carbide oxidize that can produce expansion effect, chemical reaction course will appear thus a large amount of liquid phase which leads to wet or reach the matrix combining through high-temperature plasticity with matrix. After analyzed comprehensively, prescription 4 as repairing raw materials is chose. And the ceramic ring of zirconium with macroscopic crack is repaired. The result proves, utilizing and filling a prescription 4 purposes repairing the macroscopic crack of ceramic can be realized.