Microstructure And Properties Of (Ca/Y)-α-Sialon Ceramics Synthesized From Water Quenched Blast Furnace Slag

Water quenched blast furnace slag is a byproducts during the smelting process.It's mainly used in the preparation of cement, siliceous fertilizer and so on. To increase the added value of the water quenched blast furnace slag is a dream for long. The main constituent of water quenched blast furnace slag are SiO2,Al2O3,CaO and some extraneous component comprise Fe, which is suitable raw materials for synthesizing Sialon powder. Many scholar have made extensive research about how to synthesize Sialon powder using blast furnace slag. The sintering craft of slag Sialon powder was always a challenge on account of the impurities Sialon powder usually contain. The former research all used a hot-press sintering or powder embedded sintering craft. These kinds of sintering processing have a high cost, so that the popularized is limited. The goal of this experiment is to sinter high performance Sialon ceramic using slag Sialon powder in a low cost way.The (Ca/Y)-α-Sialon ceramic were sintered using Ca-α-Sialon powder synthesized from water quenched blast furnace slag in a pressureless way. During the process, Al2O3 and Y2O3 were used as addition agents.Here we reported that how the sintering character,microstructure and mechanical property of the (Ca/Y)-α-Sialon ceramic influenced by the mixture ratio and sintering processing.We also investigated phrase, grain size, fracture mechanism of (Ca/Y)-α-Sialon ceramics by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM).The XRD analysis suggested that main phases of the samples after sintering was a-Sialon and component comprise phase is Fe-N compound. (Ca/Y)-α-Sialon columnar grains got thicker and more equiaxed with the increase of the content of Y2O3 and sintering temperature. (Ca/Y)-α-Sialon columnar grains get thicker and more equiaxed with the increase of the content of Y2O3 and sintering temperature.The results on mechanical property analysis show that proper percentages of Y2O3 in the samples could promote densification and increase the mechanical property of the material whereas more than 10 mass% Y2O3 in the sample could decrease of the density and the mechanical property. The best Y2O3 content is 10 mass%, the best sintering processing is 1700℃×1.5h. The volume density,bend strength,Vickers-hardness and fracture toughness reached 3.32 g·cm-3,238MPa,12.5GPa and 4.07 MPa·m-1/2 respectively due to the parameters.In summary, it shows that the synthesis of (Ca/Y)-a-Sialon ceramics from water quenched blast furnace slag using pressureless sintering method is a simple, low cost and high performance process. The basic research supplies a new chance for the utility of slag.