摘要
A rapid and facile approach was developed for the synthesis of ultrafine SmAlO_(3) powders through the combustion of stearic acid precursors.The obtained products were characterized by typical techniques including X-ray diffraction(XRD),Fourier Transform Infrared(FT-IR),thermogravimetric and differential thermal analysis(TG-DTA),scanning electron microscopy(SEM),and transmission electron microscopy(TEM)to analyze the phase composition and microstructure.The dielectric characteristics of SmAlO_(3) microwave ceramics,using the as-obtained products as original materials,were also studied.Compared with the conventional solid-state reaction method,the synthesis temperature was dramatically reduced to 750℃.The large-size sheet structure was composed of a number of micro/nano-scale crystallites,which were mostly irregular in shape due to the mutual growth and overlapping shapes of adjacent grains.The SmAlO_(3) ceramics with high density and uniform microstructure were obtained after sintering at 1500℃ for 4 h due to the favorable sintering activity of the as-synthesized powders.In addition,desired dielectric properties at microwave frequencies(dielectric constant ε_(r)=20.22,quality factor Q·f=74110 GHz,and a temperature coefficient of resonant frequency τ_(f)=-74.6 ppm/℃)were achieved.
基金
financially supported by the Natural Science Foundation of Anhui Provincial Education Department(Nos.KJ2019A0054 and KJ2018A0041)
the National Natural Science Foundation of China(No.51802003).
