α-TCP/TTCP骨水泥的降解性能研究

通过体外实验研究α-TCP/TTCP骨水泥在模拟体液中的溶解性能.用电子探针、X-射线显微分析(EPMA)仪、扫描电镜、X-射线能谱(EDXA)对α-TCP/TTCP骨水泥骨内植入后材料与骨组织剖面的超微结构进行研究.结果表明α-TCP/TTCP骨水泥具有一定的降解性能和成骨作用.     

常压烧结制备AlN-W复合微波衰减材料及其性能研究

以氮化铝、钨为原料,在氮气气氛下,采用无压烧结方式制备了AlN-W复合微波衰减材料.采用扫描电子显微镜、矢量网络分析仪及激光导热仪对样品的微观结构、介电性能及热导率进行测试分析.结果表明:随着烧结温度的增加,AlN-W复合陶瓷的介电常数逐渐增大,介电损耗变化不大.随着烧结助剂添加量的增加,AlN-W复合陶瓷的介电常数和介电损耗相应增大.随着W含量的增加,AlN-W陶瓷的介电常数呈增加的趋势,介电损耗逐渐降低,当W添加量为60％时损耗几乎为零.随着W颗粒粒径的增加,AlN-W复合陶瓷的介电常数变化不大,介电损耗逐渐降低.由此可通过调节烧结温度、衰减剂含量、衰减剂粒径及烧结助剂的添加量,来制备符合实际需要的复合微波衰减材料.1750℃下制备的A1 N-40％W复合陶瓷热导率为91 W/m·K.初步分析了AlN-W复合陶瓷的微波衰减机理.     

微波烧结制备碳化硅粉体的研究

以乙炔炭黑和硅粉为原料,采用微波烧结技术合成制备了粒度不同的碳化硅粉体.研究了反应温度和保温时间对碳化硅粉体产率和粒度的影响.结果表明:在900℃反应30 min,所得产物的主要物相为β-SiC和仍残余少量金属Si.随着反应温度的升高,产物中SiC的含量不断增加,残余金属Si的含量则明显下降.当反应温度升高至1100℃以上时,则得到单相的β-SiC.在1200℃下反应5min,产物中主要物相为SiC,存在着少量未反应的金属Si,当反应时间延长到15 min时,即得到单相的β-SiC.     

透辉石复合的羟基磷灰石生物陶瓷材料的制备及性能

介绍了透辉石复登在磷灰石生物陶瓷材料的工艺条件,讨论了影响其抗折强度的主要因素。     

AlN-SiC微波衰减材料的高频介电性能研究

分别采用SPS和无压烧结工艺制备了AlN-SiC微波衰减材料.采用网络分析仪及扫描电镜检测仪,研究了衰减材料在X波段和Ku波段的介电性能及微观结构.研究结果表明:SPS制备的样品相对密度达到98％,介电性能在X波段ε'为14.01 ～13.98,tgδ为0.158 ～0.163,在Ku波段ε'为11.48 ～10.96,tgδ为0.18 ～0.17;采用无压烧结制备的样品密度仅为理论密度的95％,在X波段的ε'为26.97 ～24.26,tgδ为0.326 ～0.327.探讨了两种烧结方式制备样品的损耗机理.     

氮化硅陶瓷材料微波烧结研究现状

氮化硅是一种具有优良性能的陶瓷材料,是一种理想的高温结构材料和高速切削刀具材料,近年来随着微波技术的发展,氮化硅的微波烧结越来越受关注。本文简述了氮化硅陶瓷材料传统烧结与微波烧结的研究现状;比较分析了各种烧结技术制备的氮化硅陶瓷的微观结构和力学性能,得出了微波烧结氮化硅陶瓷的优越性;最后提出氮化硅陶瓷微波烧结在未来研究中还需解决的问题。     

微波水热辅助沉淀法制备氧化铝/碳化硅复合粉体

用微波水热辅助沉淀法制得氧化铝前驱体/碳化硅复合粉体,用XRD、SEM、TG-DSC对粉体进行了表征.研究表明:经过微波水热后,氧化铝的前驱体转变为AlO(OH),随着微波水热时间延长,AlO(OH)的结晶程度越来越高.pH值为7时,煅烧后的Al2 O3/SiC复合粉体的包覆效果最佳.     

微波烧结制备陶瓷材料的研究进展

微波烧结是一种新型的利用微波加热来对材料进行烧结的方法,它是一种快速制备高质量新型材料和使传统材料具有新的性能的技术手段。简要介绍了微波烧结的发展史、基本原理、制备陶瓷材料的研究进展、微波烧结技术存在的一些问题,并对微波烧结技术的前景进行了展望。     

基于辅热材料的微波烧结陶瓷刀具温度场研究

针对微波烧结A12O3基陶瓷刀具温度场,基于辅热材料温度特性,运用Comsol Multiphysics多物理场仿真软件进行模拟仿真,研究辅热材料用量及成分配比对刀具试样升温速率及温度均匀性的影响.研究结果表明:对于大小为17 mm×17 mm×6 mm的A12O3基陶瓷刀具的微波烧结,辅热材料SiC用量为44 g时,...     

助烧剂添加量对AlN微波烧结陶瓷微结构的影响研究

本文分别以Y2O3、CaO、Dy2O3、Nd2O2与Sm2O3为助烧剂,利用微波烧结法制备了AlN陶瓷,并分析了助烧剂添加量对陶瓷样品微结构的影响。研究结果发现,当以Y2O3为助烧剂时所得陶瓷几近完全致密,且其添加量对陶瓷晶粒与晶界的形态有较大影响;当以CaO为助烧剂时,添加量较小时所得陶瓷中孔洞也很少,添加量较大时会在陶瓷中出现大孔洞;当以Dy2O3与Nd2O2为助烧剂时所得陶瓷相当致密且没有孔洞存在;当以Sm2O3为助烧剂时,添加量较小时陶瓷相当致密且没有孔洞存在,而添加量较大时会出现少量孔洞;其中以Nd2O2与Sm2O3为助烧剂时会有穿晶现象发生。     

Characterization of Thermoelectric Metal Oxide Elements Prepared by the Pulse Electric-Current Sintering Method

Thermoelectric elements consisting of the layered polycrystalline materials of Al-doped ZnO and NaCo₂O₄ were prepared using the pulse electric-current sintering (PECS) method at 900°C for 3 min. Direct contact between the polycrystalline Al-doped ZnO and the NaCo₂O₄ was obtained in a single-step process for the stacked powders. The electrical conductivities of the polycrystalline materials prepared by PECS were higher than those of materials prepared by conventional sintering, despite their porous structure. The thermoelectric voltage of the 1-mol%-Al-doped ZnO and NaCo₂O₄ polycrystalline element (measuring ∼6 mm × 3 mm × 15 mm) was 83 mV at d T = 500 K, when the junction of the elements was at 800°C.     

Influence of Cu2O on Interface Behavior of Copper/SiCp Composite Prepared by Spark Plasma Sintering

Copper/SiC_p composites were prepared by spark plasma sintering. X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy techniques were used to characterize the sintered samples. Cu₂O was found to facilitate the physical wetting at the interface through the formation of an amorphous intergranular phase. The reaction between SiC and copper was detected in the samples containing little Cu₂O. It led to the degradation of SiC reinforcements and the decrease in hardness of copper/SiC_p composites.     

微波烧结AlN陶瓷的初步研究

采用微波高温烧结工艺,制备了致密的AlN陶瓷,并初步探讨了微波烧成环境对烧结体性能的影响.结果表明:利用微波烧结AlN陶瓷,虽然在节能省时方面效果显著,但是微波烧成环境对AlN陶瓷的烧成影响比较复杂,本文着重指出烧成环境中的碳热还原气氛能极大地加快AlN陶瓷的致密化速率,但容易在AlN陶瓷晶界相内部产生气孔,使AlN陶瓷的热导率降低.     

Effect of Co-Precipitation on the Low-Temperature Sintering of Biphasic Calcium Phosphate

Three types of biphasic calcium phosphate (BCP) powders were prepared and their sintering behavior was investigated. The specific surface area and HA/TCP ratio were similar in all three specimens. Most of the densification in the co-precipitated s-BCP occurred before the β- to α-TCP phase transformation, and a maximum density of ∼95% was obtained at 1100°C. The mixture of separately precipitated and calcined hydroxyapatite (HA) and tricalcium phosphate (TCP) (m-BCP) showed a poor sintering behavior, and the apparent density was below 70% at temperatures up to 1200°C. In the commercial HA and TCP mixture (c-BCP), the low temperature sintering was poor, but densification continued without the phase transformation due to the presence of MgO, achieving almost full densification at 1200°C.     

有机泡沫浸渍法制备ZrO2泡沫陶瓷烧结过程研究

采用两种不同添加剂,用有机泡沫浸渍法制备了两种氧化锆泡沫陶瓷试样;用高温电阻炉分别在1300 ℃、1400 ℃、1500℃、1600 ℃下进行烧结制备试样;测试了在各温度下烧结试样的收缩率,用环境扫描电镜和能谱分析仪观察陶瓷的显微结构,用X射线衍射仪分析试样的物相组成.结果表明:试样的收缩主要发生在1300～1500 ℃,在1300 ℃进入烧结中期,1400～1500 ℃进入晶粒成长期,1500-1600 ℃进入晶粒异常长大期.采用MgO、CeO2复合稳定,对促进烧结、生成高温稳定相有一定作用,可以减小试样的收缩.制品中高温相的含量在1300～1500 ℃烧结温度范围内迅速增加,1500℃后逐渐减少.     

溶胶-凝胶法制备有机/无机复合疏水薄膜的研究

研究了以聚四氟乙烯(PTFE)、硅溶胶为主要原料，利用溶胶-凝胶法在玻璃表面制备了SiO2／聚四氟乙烯有机／无机复合薄膜。分别用XRD，IR，SEM，TG-DTA等测试手段分析了涂膜在热处理过程中所发生的物理-化学变化，以及薄膜材料的组成、结构、表面形貌。研究表明：在复合薄膜材料中，PTFE与SiO2形成相互贯穿的无规网状结构，薄膜与基材附着力良好，表面呈现出良好的疏水性能。     

不同烧结工艺制备耐高温高透过率氮化物复合材料的研究

对相同组分的氮化物复合材料,在不同温度段采用无压、气氛压力烧结,进行性能对比试验。分析了两种工艺研制的材料性能在不同温度下的变化规律,探讨了相同温度下不同烧成工艺对材料密度、强度、耐温性、耐烧蚀性及介电性能的影响。     

B6O–c-BN Composites Prepared by High-Pressure Sintering

High-pressure sintering behavior in the B₆O– c -BN system was investigated using in-laboratory-synthesized B₆O and commercially available c -BN powders (with an average grain size of 0.5, 3, or 6 μm). No reaction occurred between the two components under the high-pressure (4–6 GPa) and high-temperature (1500°–1800°C) conditions that have been investigated. Well-dispersed, sintered B₆O– x ( c -BN) composites (where x = 0–60 vol%) of almost-full density were prepared by sintering at a pressure of 6 GPa and temperature of 1800°C for 20 min. The maximum Vickers microhardness (46 GPa) of these composites was attained by adding 40 vol% c -BN with an average grain size of 0.5 μm. The fracture toughness of these composites increased as the c -BN content increased; the maximum fracture toughness (1.5–1.8 MPa^.m^1/2) was observed for x = 40–60 vol%. Crack deflection along the B₆O– c -BN grain boundary contributed to increasing the fracture toughness.     

烧结法制备Y-TZP/微晶玻璃复合材料的研究

用烧结法制备了Y-TZP，微晶玻璃复合材料，结合DTA分析制定了热处理制度，研究了烧结温度和Y-TZP的加入对复合材料力学性能的影响。