TiSi2提高TiB2陶瓷烧结致密性机理研究

以TiSi2作为烧结助剂,采用热压烧结制备了TiB2陶瓷.对烧结试样进行了XRD、SEM与EDS分析,对TiB2-x％ TiSi2系统进行了热力学计算分析,探讨了TiSi2促进TiB2陶瓷低温烧结致密的机理.结果表明:添加6.0wt％TiSi2作为烧结助剂,可以使TiB2陶瓷在1650℃热压烧结致密.TiSi2促进TiB2陶瓷烧结致密机理为:一是TiSi2熔点低于烧结温度,通过液相传质提高了烧结速率;二是通过高温烧结反应,形成了高熔点的Ti5Si3相以及SiO2玻璃相,SiO2以玻璃相的形式填充气孔并促进液相传质,使坯体致密.     

放电等离子烧结（SPS）技术烧结致密AlN陶瓷

利用放电等离子烧结技术烧结氮化铝,不加任何添加剂,在1800℃的烧结温度、25MPa的压力下,仅保温4min,就可达到99％的理论密度,SEM表明试样内部晶粒细小,结构均匀。实验表明,SPS技术可实现快速烧结。     

热压烧结高纯hBN陶瓷材料及其致密性研究

本文研究了B2O3和BN粉料的热行为,分析了未处理的BN陶瓷的物相特性,采用除杂处理后的BN原料,热压烧结制备了高纯BN陶瓷材料,分析了影响陶瓷材料弯曲强度和致密性的主要因素,探讨了BN晶粒的定向性与热压工艺之间的关系.     

热压烧结BN-AlN复相陶瓷致密化研究

研究了热压烧结BN-AlN复相陶瓷的致密化行为，研究了添加剂的加入量、AlN第二相的含量以及热压温度、保温时间等工艺参数对复相陶瓷致密化的影响。结果表明：当Y2O3的添加量为10％，AlN加入量为50％时，在1900℃，保温2h，压力为30MPa，N2气氛下可以制备出致密的BN—AlN复相陶瓷，对BN—AlN的相组成及显微结构进行了观察分析。     

热压烧结制备粉煤灰建筑陶瓷的工艺研究

以固体废弃物粉煤灰为主要原料,通过对原料进行预烧处理工艺得到活化粉煤灰粉体,分别在850 ℃、875℃、900 ℃、925 ℃、950 ℃度进行真空热压烧结,制备粉煤灰建筑陶瓷复合材料.利用XRD对复合材料的物相组成进行分析、采用SEM分析样品的微观结构,结合烧成样品的吸水率、体积密度、硬度等,分析不同的烧结温度对陶瓷性能的影响.结果表明:真空热压烧结过程中,随着温度升高,样品低共熔相增多,致密化程度增加.当烧结温度达到925℃时,所得复合陶瓷材料晶粒分布均匀、细小,晶粒尺寸为0.4~0.5 μm;陶瓷样品的体积密度、吸水率、硬度分别为2.62 g/cm3、0.05%、6.5 GPa.     

碳化硼陶瓷的无压烧结

按照不同的实验方案对碳化硼原料进行烧结,结果发现在2 108~2 226℃下进行无压烧结能得到高纯碳化硼制品,使用Al气和由SiC制得的Si气做为助烧结气,在2 226℃可得到高致密性的B4C制品,体积密度为2.455g.cm-3,约为理论密度的97.4%。     

烧结工艺对石英质多孔陶瓷性能的影响

以石英砂为主要原料,采用液相烧结法,经半干压成型制备石英质多孔陶瓷.采用SEM对多孔陶瓷的显微结构进行表征.探讨了烧结温度、保温时间对多孔陶瓷孔隙率及断裂强度的影响.结果表明:随着烧结温度升高,保温时间延长,石英质多孔陶瓷的孔隙率下降、断裂强度不断增大;最佳烧结温度为1250℃,最佳保温时间为30 min.在最佳烧结工艺条件下,制备得到高孔隙率陶瓷,孔结构单一且孔径分布较窄,平均孔径大约为12.41μm.     

β-氮化硅陶瓷烧结致密化的研究

以β-Si3N4粉末为原料,MgAl2O4为烧结助剂,通过气氛压力烧结(GPS)制备出致密的β-氮化硅陶瓷材料,探讨了β-氮化硅陶瓷烧结机制,系统研究了烧结助剂质量分数、烧结温度以及保温时间对材料致密化的影响.     

AIN陶瓷的烧结致密化与导热性能

氮化铝陶瓷具有高热导率，低介电常数，与硅相匹配的热膨胀系数等优良特性，应用领域非常广泛，对AIN粉体的合成，烧结工艺，助烧结剂及其应用等方面进行了介绍，并对AIN未来的发展趋势进行了展望。     

烧成温度对多孔SiC陶瓷管性能的影响

以SiC为骨料,添加低共熔混合物烧结促进剂,煤粉作为造孔剂,在不同的温度下烧成制备多孔陶瓷管.考察了烧成温度对多孔SiC陶瓷管的孔隙率、气体渗透通量、孔径分布以及抗弯强度等性能的影响,并通过SEM对其结构形貌进行了表征.结果表明:随着烧成温度的提高,孔隙率、气体通量及抗弯强度下降,孔径分布变宽.     

BN基复合陶瓷致密化的主要障碍

本文对ＢＮ基复合陶瓷进行了热压和无压烧结试验,对烧结体的密度变化和显微结构进行了研究,分析了影响ＢＮ基复合致密化的主要因素,认为卡片房式结构是妨ＢＮ基复合陶瓷致密化的主要原因。热压过程中施加的压力足够大时,可以破坏这种卡片房式结构,使片状ＢＮ定向排列,因而能获得同致密度的ＢＮ基复合陶瓷,热压过程中若有液相出现,有利于片状ＢＮ定向排列,因而能促进ＢＮ基复合陶瓷的致密化。无压烧结因不能消除坯体中的卡片     

Rapid Rate Sintering of Yttria Transparent Ceramics

This paper reports on the influence of rapid rate sintering (RRS) on densification and microstructure evolution of yttria transparent ceramics by using vacuum sintering. The presence of temperature gradient has been confirmed during the RRS process. The higher the heating rate (HR), the larger the temperature gradient in the samples would be. By using RRS, e.g., HR = 40°C/min, the samples could be densified very fast to a relative density of 99.6%. However, these samples could not be further densified, due to the presence of difference in densification caused by a heating rate‐induced temperature gradient. By using a two‐step RRS with an intermediate‐temperature thermal treatment, this problem has been successfully addressed. The intermediate‐temperature treatment allowed for the particle neck growth, so that effective thermal conductivity of the compacts was increased greatly. Therefore, the temperature gradient and differentiate densification were effectively prevented. Samples sintered using the two‐step RRS process could be fully densified and excellent in‐line optical transmittance was achieved. It is believed this strategy is applicable to other transparent ceramics, as well as other engineering ceramics.     

常压烧结制备氧化钨陶瓷靶材的致密化研究

采用常压固相烧结工艺,制备出高纯度、高致密度的氧化钨靶材。考察了粉体粒度、成型压强、烧结温度和保温时间等对靶材致密度的影响。测试结果表明,以粒度0.27μm的粉体为原料,成型压强为60MPa,烧结温度为1200℃,保温时间为1h的条件下,可以制备出高致密度的氧化钨靶材,其组成为高纯的单斜晶相。     

Effect of Green Density on Densification and Creep During Sintering

The effect of green density on both the densification rate and the creep rate was measured simultaneously during sintering by loading dilatometry. The experiments were performed on zinc oxide powder compacts with five different green densities covering a range of 0.39 to 0.73 of theoretical. The samples were heated at a constant rate of 4°C/min up to 1100°C in air. The densification rate at any temperature increases significantly with decreasing green density. The data for the densification rate and creep rate as a function of density show two quite distinct regimes of behavior; the rates were strongly dependent on density below 0.80, while above this value they were weakly dependent on density. The ratio of the densification rate to the creep rate was almost independent of temperature but increased almost linearly with increasing green density. The representation of the data in terms of models for sintering and creep is discussed.     

先进陶瓷材料快速烧结技术发展现状及趋势

快速烧结技术在节省时间和能源方面的巨大优势使其成为一直以来的研究热点.近几十年来,快速烧结技术(如火花等离子烧结、闪电烧结、选区激光烧结、感应烧结、微波烧结和传统烧结装置中的快速烧结等)的发展,使陶瓷材料的快速烧结成为可能.本文综述了近20年来先进陶瓷领域中的快速烧结技术和烧结机理,并对火花等离子烧结中直流脉冲电流和机...     

High-Pressure Self-Combustion Sintering of Alumina-Titanium Carbide Ceramic Composite

Al₂O₃-TiC ceramic composites were fabricated by highpressure self-combustion sintering (HPCS). The samples had a unique microstructure which was quite different from that of commercial Al₂O₃-TiC materials made by conventional processing. A possible mechanism for combustion reaction is suggested on the basis of the microstructure of the samples and the thermodynamical data. The HPCS sample had a higher K _IC value than commercial Al₂O₃-TiC materials.     

降低高铝瓷烧成温度的研究

从我国能源战略的高度和高铝瓷产业生存、发展的角度,阐述论证了低温烧成的必要性和重要性.基于高铝瓷烧结的内在规律和固有特点,指出低温烧结对高铝瓷性能有改善作用,提出了几种降低高铝瓷烧成温度的可行技术方案.