【作者】 张丽；

【导师】 徐久军；

【作者基本信息】 大连海事大学 ， 材料科学与工程， 2010， 硕士

【摘要】 本文以Si3N4、AlN、A12O3和Y203为原料,根据Y-Si-Al-O-N相图和a-sialon分子式Rem/3Si12-(m+n)Al(m+n)OnN16-n进行组成设计,取m=1.2,n=1.1为组分点。原料粉末用行星式球磨机球磨24 h后,经烘干、造粒,采用热压烧结方法在氮气环境中进行烧结,压力为25 MPa。采用X射线衍射(XRD),扫描电子显微镜(SEM)和紫外／可见分光光度计研究球磨机转速、烧结温度、升温速率以及保温时间对sialon陶瓷物相组成、微观结构和光学性能的影响规律,并对sialon陶瓷进行了硬度表征。研究结果表明：当球磨机转速由210r/min提高到250 r/min时,原料粉末的平均粒度由0.603μm降到0.207μm；在相同的烧结工艺条件下所制备的陶瓷物相组成均为a-sialon;当球磨机转速为250 r/min时陶瓷的晶粒尺寸比球磨机转速为210r/min时陶瓷的晶粒尺寸小,且样品表面呈现暗绿色,该现象与烧结温度过高的sialon陶瓷状态一致。对250 r/min混出的粉料,烧结工艺研究表明：在升温速率为30℃/min,保温时间为30 min条件下,当烧结温度由1650℃升高到1900℃时,陶瓷的相组成均为a-sialon,而体积密度和晶粒尺寸增大；烧结温度为1650℃时a-sialon陶瓷透过率最低,烧结温度为1700℃时a-sialon陶瓷的透过率最大,为34.43%,随着烧结温度进一步升高直到1900℃,陶瓷的透过率降低；当烧结温度为1700℃,保温时间为30 min时,升温速率由30℃/min提高到38.5℃/min,陶瓷均生成了a-sialon相,体积密度降低,晶粒尺寸减小,透过率降低；当烧结温度为1700℃,升温速率为30℃/min时,保温时间由30 min降到15 min时,陶瓷均为a-sialon相,但晶粒尺寸减小、透过率降低。对250r/min混出的粉料,当烧结温度为1700℃,升温速率为30℃／min,保温时间为30 min时所制备的Y-a-sialon陶瓷透过率最高,在1100 nm处的透过率为34.43%,硬度为19.10 GPa,该陶瓷的透过率比当球磨机转速为210 r/min时制备的陶瓷略高,但烧结温度却降低了200℃。更多还原

【Abstract】 In this paper, Si3N4, AlN, Y2O3, A12O3 as raw materials, under the Y-Si-Al-O-N phase diagram and the a-sialon formula Rem/3Si12-(m+n)Al(m+n)OnN16-n for component design, obtained m = 1.2, n = 1.1 for the component points. The powders, after planetary ball milling for 24 hours, then drying, granulation, were sintered by hot sintering in nitrogen environments, under the pressure of 25 MPa. Ball milling speeds, sintering temperatures, heating rates and holding times on the phase composition of sialon ceramics, microstructure and optical properties were studied, by X-ray diffraction (XRD), scanning electron microscopy (SEM) and LabTeach UV/visible spectrophotom-eter.The results showed that the average particle size of powder after ball milling reduced from the 0.603μm to 0.207μm. The powers were sintered as the same method. The ceramic phase of the samples were a-sialon. The grain size of the sample, which was prepared with the powders mixed by the speed 250 r/min, was smaller than it when the speed was 210 r/min. The powders mixed by 250 r/min milling after sintered were dark green, the phenomenon consistent with sialon ceramics under too high sintering temperature sintering.To 250 r/min mixed with the powder out of this study, sintering process showed that at a heating rate of 30℃/min,30 min holding time, the ceramic phases were a-sialon, when the sintering temperature increased from 1650℃to 1900℃. The density and the grain size increased with sintering temperature increasing. When the sintering temperature was 1650℃, the transmission was the lowest. When the sintering temperature was 1700℃, the transmission of sialon ceramic was the highest-34.43%. As the sintering temperature further increased, until 1900℃, ceramics’ transmission decreased. When the sintering temperature was 1700℃, holding time 30 min, heating rate from the 30℃/min up to 38.5℃/min process, with the increase of heating rate, material density decreased, grain size decreased, the max transmission reduced. When the sintering temperature was 1700℃, heating rate 30℃/min, the holding time from 30 min down to 15 min, the ceramics’ density decreased, grain size decreased, transmittance decreased.To the powders mixed when the milling speed was 250 r/min, the Y-α-sialon ceramic’ transmittance was the highest when the sintering temperature was 1700℃, the heating rate was 30℃/min, and the holding time was 30 min.When the wavelength was 1100 nm, it’s transmittance was 34.43%, and it’s Vickers hardness was 19.10 GPa. Compared with the ceramic’s, when the milling speed is 210 r/min, the transmittance increased 1.64%, while the sintering temperature is decreased 200℃.更多还原