直接金属氧化法制备SiCp/Al2O3-Al复合材料

利用直接金属氧化法制备了SiC颗粒增强Al2O3-Al基复合材料，借助于XRD和光学显微镜对该复合材料的组成及微观结构进行了观察，分析了SiO2层、合金成分和制备温度对复合材料性能的影响。结果表明：该复合材料结构致密且渗透完全，微观结构由三种相互穿插相组成：SiC预制体、连续的Al2O3基体及呈网状结构分布的未被氧化的残余铝合金。     

SiO_2溶胶直接静电纺产物的微观形貌和形成机理

以正硅酸乙酯(TEOS)为原料,采用溶胶凝胶和静电纺联合技术获得了SiO2凝胶纤维膜。研究了SiO2溶胶直接静电纺产物微观形貌与其粘度的相互关系。FESEM观察结果表明,当陈化时间适当时(47 h),SiO2溶胶的粘度为200～350 mPa.s,具有较好的静电纺能力,可获得纤维直径为2.5μm左右的尺寸均匀和无节珠的凝胶纤维膜。     

SiO2包覆对SrAl2O4:Eu2+,Dy3+及其复合涂层发光性能影响

以正硅酸乙酯(TEOS)为前驱体,采用溶胶-凝胶法制得SiO2-SrAl2 O4包覆粉体,利用超音速等离子喷涂技术在45#钢基体上制备了Cu-14Al-X/SrAl2 O4(未包覆/包覆)复合涂层.采用扫描电子显微镜、X射线衍射仪和激光粒度分析仪对SrAl2 O4:Eu2+,Dy3+磷光粉和SiO2-SrAl2 O4包覆粉体进行表征.利用荧光分光光度计对包覆前后磷光粉及Cu-14Al-X/SrAl2 O4(未包覆/包覆)复合涂层的发光性能进行分析,探究超音速等离子喷涂过程中SiO2表面包覆防猝灭工艺效果.结果表明:SiO2包覆膜层未改变SrAl2O4:Eu2+,Dy3+磷光粉的晶体结构,对磷光粉的发光性能影响不大,可起到有效的隔离和保护作用,使磷光粉的发光性能得到改善,防猝灭效果较好.     

复合化学气相沉积法制备厚膜α-Al_2O_3涂层硬质合金刀具

研究了厚膜α-Al2O3涂层硬质合金刀具的涂层设计方法,探索了采用中、高温连续复合化学气相沉积技术(MHT-CVD)生产厚膜α-Al2O3涂层硬质合金刀具的工艺,表征了复合涂层的微观结构,并对厚膜α-Al2O3涂层硬质合金刀具的性能进行了测试。研究表明,通过MHT-CVD工艺生产的厚膜α-Al2O3涂层硬质合金刀具具有比普通TiN涂层硬质合金刀具更佳的切削性能。     

复合电铸Ni-La2O3纳米复合材料的组织结构和性能

采用复合电铸工艺制备了不同La2O3纳米颗粒含量的Ni—La2O3纳米复合材料，用扫描电子显微镜和X射线衍射仪观察分析了纳米复合材料的表面形貌及组织结构，与电沉积纯镍作对比研究了纳米复合材料的显微硬度和耐磨损性能。结果表明，由于La2O3纳米颗粒的存在，导致Ni-La2O3纳米复合材料的组织结构发生了改变，它比纯镍沉积层具有更高的显微硬度及耐磨性，且La2O3纳米颗粒质量分数越大，纳米复合材料的显微硬度越高，耐磨性越好。     

与Y2O3共同掺杂下Sb2O5掺杂量对SnO2陶瓷压敏电阻电性能的影响

通过在SnO2陶瓷压敏电阻中共同掺杂Sb2O5和Y2O3(0.05％,物质的量分数),采用扫描电镜和阻抗仪研究了Sb2O5掺杂量(0,0.05％,0.10％,0.15％,物质的量分数)对SnO2压敏电阻微观形貌、电压梯度和晶粒电阻的影响.结果表明:随Sb2O5掺杂量增加,SnO2压敏电阻的晶粒尺寸和界面态密度先增大后减小,电压梯度、非线性系数和泄漏电流密度先减小后增大;Sb2O5掺杂量为0.10％时,SnO2压敏电阻的界面态密度最大,泄漏电流密度最小,晶粒电阻最小,综合电性能最好.     

纳米α-Al_2O_3和γ-Al_2O_3颗粒增强镍-磷复合镀层的性能对比

采用化学镀技术制备了纳米α-Al2O3和γ-Al2O3颗粒增强的镍-磷复合镀层,利用X射线衍射仪、扫描电子显微镜、电子探针等对复合镀层的物相结构、表面形貌、成分分布进行了分析,还对比了复合镀层与镍-磷镀层的显微硬度、耐磨性和耐腐蚀性。结果表明:与镍-磷镀层相比,纳米Al2O3颗粒的加入没有改变镀层的晶体结构,但使镀层的显微硬度明显提高;纳米α-Al2O3颗粒的加入提高了镀层的耐腐蚀性和耐磨性,而纳米γ-Al2O3颗粒的加入反而使镀层耐磨性和耐腐蚀性下降。     

TiC／（Al2O3／Y-TZP）纳微米复合陶瓷材料的性能及显微结构研究

采用热压烧结制备了TiC/(Al2O3/Y-TZP)纳微米复合材料,用SEM观察了复合材料断口形貌和微观结构,研究了纳米TiC含量对复合材料的力学性能的影响,结果表明:20%TiC(15%Al2O3/5Y-TZP)复相陶瓷抗弯强度和断裂韧性高达620MPa、6.8MPa·m1/2.     

SiO_2-Si_3N_4-SiO_2复合梁谐振式压力传感器结构设计与分析

提出了一种采用SiO2-Si3N4-SiO2复合谐振梁结构的谐振式压力传感器。采用有限元分析技术分别对谐振梁和传感器芯片结构进行了电热分析、模态分析以及谐响应分析,最后对SiO2-Si3N4-SiO2复合梁谐振式压力传感器的工艺进行了探讨,表明通过多晶硅牺牲层技术能更好地得到Si O2-Si3N4-Si O2复合谐振梁,具有良好的选频特性。     

锡掺杂量对In_2O_3粉体光学性能和形貌的影响

采用固相反应法在800℃烧结制备出了不同锡掺杂量的(In1-xSnx)2O3(x=0,0.01,0.02,0.05)粉体,通过X射线衍射仪(XRD)、拉曼光谱仪、傅里叶红外光谱仪(IR)、紫外吸收可见光谱(Uv-vis)分析仪以及扫描电镜(SEM)等对(In1-xSnx)2O3粉体的结构、光学性能和形貌进行了表征。结果表明:不同锡掺杂量的(In1-xSnx)2O3粉体都保持了In2O3的立方相晶胞结构;锡的掺杂改变了In2O3的紫外-可见吸收性能和红外吸收性能,抑制了In2O3粉体颗粒的长大,使其结构变得更加紧密。     

陶瓷-玻璃-单晶硅的阳极键合工艺性研究

首先采用射频磁控溅射法在ZrO2陶瓷基体上沉积一层钠硼硅酸盐玻璃，并通过该钠硼硅酸盐玻璃薄膜作为中间层利用阳极键合方法实现了ZrO2陶瓷与单晶硅的间接连接。     

Preparation and characterization of TiO_2-SiO_2-Fe_3O_4 core-shell powders in nano scale

TiO2/SiO2/Fe3O4 nanoparticles have bigger specific area which can greatly increase the efficiency of photo-catalysis.The TiO2/SiO2/Fe3O4 particles in nano scale were prepared with reduction method at high temperature in this paper,and their morphology,particle size and magnetic property were characterized by transmission electron microscope(TEM),Xray diffraction(XRD) and magnetometer.The results show that the grain sizes of Fe3O4,SiO2-Fe3O4 and TiO2-SiO2-Fe3O4 particles were 50nm,70nm and 120nm,respectively.With the modification of SiO2,Fe3O4 magnetic cores are protected from oxidation.Moreover,by the addition of TiO2 function layer,TiO2-SiO2-Fe3O4 functional nanoparticles,with the saturation magnetization density of 34.1emu/g,is magnetically recoverable.The processes of this method are so simple that the nanoparticles can be produced in large quantity.     

Characteristics of Sputter-deposited Gadolinia-doped Ceria Thin Films on Al2O3/SiO2/Si Systems

Metal oxide films prepared by thin film technology have been reported for the potential applications on thin solid electrolyte layers for solid oxide fuel cells(SOFCs). Gadolinia-doped ceria(GDC) thin films and Al2O3 layers on SiO2/Si substrates are successively deposited by RF reactive magnetron sputtering from a cerium-gadolinium (90:10 at.%) alloy target and Al target in O2/Ar gas mixture and then perform post-thermal treatments at 300-700 ℃ and 900 ℃ for 2 h, respectively. Materials characteristics and chemical compositions of GDC films and Al2O3 layers are investigated by X-ray photoelectron spectroscopy(XPS), cross-sectional scanning electron microscopy(SEM), X-ray diffraction(XRD), and atomic force microscopy(AFM). Stoichiometric Al2O3 layers with polycrystalline structures are firstly prepared onto SiO2/Si substrates. A cubic fluorite structure with columnar crystallites of GDC films is successfully deposited on Al2O3/SiO2/Si systems. The chemical composition of 700 ℃-annealed GDC films is (Ce0.91Gd0.09)O1.94 and possesses a higher film density of 7.257 g/cm3. As a result, GDC thin films prepared by RF reactive magnetron sputtering and post-thermal treatments can be used as thin solid electrolyte layers for intermediate temperature SOFCs system as compared to the well-known yttria-stabilized zirconia(YSZ).     

电解液中Na2CO3/C6H12O6对AZ31镁合金阳极氧化膜结构与耐腐蚀性能的影响

在添加不同含量Na2CO3和C6H12O6的NaOH-Na2SiO3-Na2B4O7基础电解液中,对AZ31镁合金进行直流阳极氧化处理,研究了镁合金阳极氧化膜的微观结构以及在中性盐雾中的耐腐蚀性能。结果表明:镁合金阳极氧化膜主要由MgO相和Mg2SiO4相组成;电解液中添加Na2CO3和C6H12O6后,阳极氧化膜表面微孔分布均匀且尺寸减小,阳极氧化膜厚度增加;当Na2CO3质量浓度由10g·L^-1增加到30g·L^-1时,微孔尺寸增大,氧化膜厚度减小;当C6H12O6质量浓度由5g·L^-1增加到15g·L^-1时,微孔尺寸减小,阳极氧化膜厚度增加;镁合金阳极氧化膜的主要腐蚀形式为点蚀,呈河流状花样分布;电解液中添加10g·L^-1 Na2CO3时,阳极氧化膜表面微孔最细小,孔径为1~3μm,阳极氧化膜厚度达16μm,阳极氧化膜具有较好的耐腐蚀性能。     

溶胶-凝胶法制备碳纳米管/SiO_2复合材料过程的TG-DSC-MS研究

利用热重 -差示扫描量热 -质谱 ( TG-DSC-MS)联用技术对溶胶 -凝胶 ( Sol-Gel)法热压烧结制备碳纳米管 ( CNT) /Si O2 复合材料过程中的热分解行为特性进行了表征研究。采用多离子检测模式预定测量热分解生成的 C+ ( m/z1 2 )、OH+ ( m/z1 7)、H2 O+ ( m/z1 8)、CO2 + ( m/z2 8)等 9种正离子。实验发现 :用溶胶 -凝胶法制备 CNT/Si O2 复合材料过程中 ,在 5 0 0℃以下生成 Si O2 ,CNT在 5 0 0～ 73 0℃左右氧化燃烧。在 5 0 0℃条件下煅烧 1 h,凝胶 Si O2 完全转变成玻璃粉。选择在 5 0 0℃条件下煅烧 CNT/Si O2 复合粉体 1 h可作为CNT/Si O2 复合材料的煅烧工艺     

Al_2O_3-SiO_2系纤维增强ZL109合金复合材料的高温蠕变特性

用加压铸造法制取Al2 O3 SiO2 系纤维增强ZL10 9合金复合材料 ,研究了在不同温度和不同试验应力下复合材料和ZL10 9合金的高温蠕变特性。结果表明 :经纤维增强的复合材料 ,在5 73K下的蠕变极限强度是ZL10 9合金的 1 2倍 ,在 673K的蠕变极限强度是Z10 9合金的 4倍 ,但复合材料的蠕变断裂具有突发性。     

粉末X射线衍射分析法鉴定乙烯球罐外输泵出口过滤网堵塞物样品中晶体物相

采用粉末X射线衍射(PXRD)分析法鉴定了乙烯球罐外输泵出口过滤网堵塞物样品中晶体物相。相鉴定结果为:Fe2O3(赤铁矿PDF#33-0664),Fe+3O(OH)(针铁矿PDF#29-0713),Fe+3O(OH)(纤铁矿PDF#44-1415),CaCO3(方解PDF#05-0586)和SiO2(石英PDF#46-1045)。目视检测发现,堵塞物样品中还含有大量纤维。本试验对乙烯球罐外输泵出口过滤网堵塞故障技术分析与技改具有指导意义。     

ZrO2对激光烧结Al2O3/SiO2/ZrO2显微组织和显微硬度的影响

在Nd:YAG激光器低功率烧结的条件下,基于选择性激光烧结工艺（SLS）成形复相陶瓷Al2O3/SiO2/ZrO2材料,利用扫描电子显微镜（SEM）、X射线衍射分析仪（XRD）和显微硬度计分别对激光烧结层加入ZrO2前后的表面形貌和断口形貌、表面物相、表面显微硬度进行了分析。结果表明,部分四方相ZrO2(t-ZrO2)相变成单斜相ZrO2(m-ZrO2),应力诱导微裂纹增韧作用和Al2O3弥散强化共同作用在某种程度上提高了烧结试样的断裂韧性,对于改善零件整体寿命和可靠性有着重要的意义。     

PMMA/SiO_2纳米复合材料的断面原子力显微镜分析

原位聚合法制备PMMA/nano-SiO2纳米复合材料,用DSC,TGA和溶解实验研究复合材料基本的结构和性能。用AFM对复合材料的断面进行详细的分析。结果表明,经表面处理的SiO2无机填料在低含量的情况下可以分散的比较均匀;高含量SiO2很难在PMMA基体中分散均匀,而且使PMMA的断面变得较为粗糙。SiO2填充粒子的添加和用量对基体的热稳定性、玻璃化转变温度、材料的溶解性都有较大的影响。     

Cryo-X-ray analysis-A novel tool to better understand the physicochemical reactions at the bioglass/biological fluid interface

The present study deals with the short-term physicochemical reactions at the interface between bioactive glass particles [55SiO(2)-20CaO-9P(2)O(5)-12Na(2)O-4MgO. mol%] and biological fluid (Dulbecco Modified Eagle's Medium (DMEM)). The physicochemical reactions within the interface are characterized by scanning transmission electron microscopy (TEM) (STEM) associated with Energy-dispersive X-ray spectroscopy (EDXS). Microanalysis of diffusible ions such as sodium, potassium, or oxygen requires a special care. In the present investigation the cryo-technique was adopted as a suitable tool for the specimen preparation and characterization. Cryosectioning is essential for preserving the native distribution of ions so that meaningful information about the local concentrations can be obtained by elemental microanalysis. The bioglass particles immersed in biological fluid for 24 h revealed five reaction stages: (i) dealkalization of the surface by cationic exchange (Na(+), Ca(2+) with H(+) or H(3)O(+)); (ii) loss of soluble silica in the form of Si(OH)(4) to the solution resulting from the breakdown of Si--O--Si bonds (iii); repolymerization of Si(OH)(4) leading to condensation of SiO(2)); (iv) migration of Ca(2+) and PO(4) (3-) to the surface through the SiO(2)-rich layer to form CaO-P(2)O(5) film; (v) crystallization of the amorphous CaO-P(2)O(5) by incorporating OH-- or CO(3) (2-) anions with the formation of three different surface layers on the bioactive glass periphery. The thickness of each layer is approximately 300 nm and from the inner part to the periphery they consist of Si--OH, which permits the diffusion of Ca(2+) and PO(4) (3-) ions and the formation of the middle Ca--P layer, and finally the outer layer composed of Na--O, which acts as an ion exchange layer between Na(+) ions and H(+) or H(3)O(+) from the solution.