Considering the lack of an effective anti-oxidation protective layer for the oxidation process of Ti3SiC2, an in situ synthesis of Ti3SiC2 and Al2O3 was designed. Thermally stable Al2O3 was used to improve the high-temperature oxidation resistance of Ti3SiC2. Samples without TiC were selected for the oxidation test, and the oxidation morphology and weight gain curves of the oxidized surface in air at 1400 °C are reported. The change in the oxidation behavior occurred 4 h after oxidation. The addition of Al2O3 changed the composition of the oxide layer and compensated for the lack of a dense protective layer during Ti3SiC2 oxidation. Moreover, after 4 h of oxidation, the newly generated Al2TiO5 and the composite layer formed by diffusion were the main reasons for the large difference in the final weight gain between the two sets of samples.
Ti3SiC2/Al2O3 multilayered composites were prepared by the combination of tape casting and hot pressing sintering. The slurry was produced by adjusting the amounts of each organic material, including triethyl phosphate (TEP) as a dispersion, polyvinyl butyrate (PVB) as a binder, dioctyl phthalate (DOP) as a plasticizer, and anhydrous ethanol as an organic solvent. When TEP content was 3 wt.%, PVB content was 4.5 wt.%, R‐value (DOP/PVB) was 1.4, and solid content was 38 wt.%; the cast film with a smooth surface, good flexibility, and uniform thickness was obtained after defoaming, tape casting, and drying. Three samples were prepared, namely, S1–S3. The S1 was monolithic Ti3SiC2/Al2O3 (mass ratio is 1:1) composites. S2 and S3 were Ti3SiC2/Al2O3 multilayered composites, which matrix layers were Ti3SiC2/Al2O3 composites (mass ratio is 1:1) and Al2O3, respectively, and their interface layer was Ti3SiC2. S1–S3 were also sintered at 1550°C. The bending strength of multilayered materials were lower than that of monolithic material, but the fracture toughness of multilayered materials significantly increased. Due to the introduction of Ti3SiC2 interface layer, the friction coefficient and wear rate of Ti3SiC2/Al2O3 multilayered composites were reduced by 30.7% and 33.8%, respectively, compared with monolithic material.
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