Abstract:
7% mass fraction of SiO
2and 2%, 4% and 6% mass fraction of Na
2B
4O
7 were added as additives into the system of A1-Fe
2O
3 to examine their effects on the microstructures and properties of ceramic compound pipes made by centrifugal SHS (self-propagating high temperature synthesis) process. It was found that ceramic layer is mainly composed of α-Al
2O
3, FeAl
2O
4, Al
2SiO
5 and B
2O
3 by XRD analysis. The surfaces on ceramic layer by SEM are much denser than that without additives, and Fe is also found in ceramic layer combined with the EDS analysis. The results show that inner ceramic layer and transition iron layer combine well without any gap observed by metallurgical microscope. It is also found that the shearing strength of the ceramic layer and crushing strength of the composite pipe under 7%SiO
2+4%Na
2B
4O
7(mass fraction) are 22 MPa and 430 MPa, respectively, which are 240% and 22.8% greater than those without additives.