自蔓延高温合成法制备TiN陶瓷粉末

采用自蔓延高温合成法（ＳＨＳ）制备了ＴｉＮ陶瓷粉末，研究了压坯密度，稀降剂掺加及氮气分压对合成过程和合成转化率的影响．结果表明：采用ＳＨＳ法制备的ＴｉＮ是由ＴｉＮ及少量Ｔｉ的固溶体构成的，通过改变工艺参数，可以得到高纯度的ＴｉＮ．影响ＴｉＮ转化率的关键因素是Ｔｉ粉与氮气的有效接触面积和氮气向反应区的转输速度．     

堇青石-莫来石复相陶瓷制备

以MgO-Al2O3-SiO2三元相图为依据,采用不同原料进行堇青石-莫来石复相陶瓷材料配料组成的设计,并在高温下合成制备了堇青石-莫来石复相陶瓷材料.研究了堇青石含量、不同原料配方对试样性能的影响.试验结果表明:配料一的试样性能较好,抗折强度均达35 MPa以上.     

块体Ti_2AlN/TiN复合材料的制备

在合成Ti2Al N配比的基础上原位引入15%体积含量的Ti N,在原位热压(HP)和放电等离子(SPS)两种烧结工艺条件下合成了块体Ti2Al N/Ti N复合材料。通过X射线衍射(XRD)分析烧结产物的相组成,用扫描电镜(SEM)和电子探针(EPMA)结合能谱仪(EDS)研究材料的显微结构特征。原位热压工艺合成Ti2Al N/Ti N复合材料的最佳温度为1 300℃,烧结试样的密度为4.30 g/cm3,达到理论密度的96.2%;放电等离子烧结工艺合成Ti2Al N/Ti N复合材料的最佳温度为1 200℃,烧结试样的密度为4.23 g/cm3,达到理论密度的94.7%。Ti2Al N和Ti N相均有团聚现象,Ti2Al N为片状形貌,晶粒发育完善,具有明显的层状结构特征;Ti N为尺寸1～2μm的四方小颗粒。     

以木材为模板制备TiN/C多孔陶瓷

利用TiO2溶胶浸渍松木木炭模板形成TiO2/C复合体,并经高温碳热-氮化反应制备了一种具有木材管胞组织结构的多孔TiN陶瓷;利用X射线衍射对氮化后的物相进行分析,采用扫描电镜对多孔TiN/C陶瓷的形貌进行观察,研究了氮化温度、气氛分压、TiO2/C质量比对最终产物TiN/C多孔陶瓷的晶体结构、微观形貌的影响.试验结果表明,当氮化条件为1400℃、4h时,可得到立方相结构的TiN陶瓷;在木炭转变为多孔TiN陶瓷的氮化过程中,木炭的显微结构很好地保留在多孔TiN陶瓷中.并通过热力学计算探讨了TiN陶瓷转化过程的机理.     

中温烧结0.6Mg_4Nb_2O_9-0.4SrTiO_3复相陶瓷

采用传统固态反应方法制备0.6Mg4Nb2O9-0.4SrTiO3复合陶瓷。研究LiF掺杂对其烧结特性、相结构和微观形貌的的影响。通过X射线衍射(XRD)和扫面电镜(SEM)观察样品的相组成和显微结构。实验结果表明:1.5 wt%LiF添加,可将Mg4Nb2O9/SrTiO3陶瓷的致密化烧结温度从1300℃降至1100℃;XRD表明除主相Mg4Nb2O9、SrTiO3外,还有少量新相Sr(Ti1-xNbx)O3+δ生成。     

多层复合TiN镀层的研究进展

TiN镀层已获得广泛的应用.为克服单一TiN镀层的不足和进一步改善TiN镀层的性能,近年来,对TiN镀层进行了深入的研究.本文综述了多层复合TiN镀层研究的最新进展,详述了TiN/氮化、TiN/Ni-P、TiN/TaN、TiN/SiC、TiN/TiCrN/CrN/CrTiN、Ti(C,N)/TiN、TiN-MoS2/Ti、TiN-DLC多层复合镀层的工艺、结构和性能,指出了今后TiN镀层的研究方向.     

膨润土-高吸水性复合树脂的制备

采用水溶液共聚法，以过硫酸铵为引发剂，N，N’-亚甲基双丙烯酰胺为交联剂，在丙烯酸和丙烯酰胺共聚交联反应的基础上添加膨润土，合成膨润土-高吸水性复合树脂(BSAC)．系统研究了交联剂、引发剂、膨润土的添加量对BSAC的吸水性和吸盐水溶液性能的影响．引发剂、交联剂、膨润土的添加量分别为单体质量的3．4‰、0．6‰和10‰时，制备出来的BSAC吸收蒸馏水和0．9％NaCl溶液的倍数分别为1100和110，并具有较好的耐热性，其在降低树脂成本及提高树脂的综合性能方面具有使用价值。     

中温烧结Mg_4Nb_2O_9-CaTiO_3陶瓷相结构的研究

采用传统固态反应方法制备了(1-x)Mg4Nb2O9+xCaTiO3[(1-x)MN-xCT]复合陶瓷。探讨了烧结温度、组分x对Mg4Nb2O9/CaTiO3复合材料相结构的影响。通过XRD和EDS进行物相分析。实验结果表明:V2O5添加能够有效降低Mg4Nb2O9/CaTiO3陶瓷的烧结温度;(1-x)MN-xCT复相的形成主要取决于烧结温度和x的含量。1150℃烧结、0.5≤x≤0.7范围内,形成了Mg4Nb2O9/CaTiO3复相,无新相生成,但元素在不同相之间发生了扩散。     

Dielectric tunable properties of BaTi_4O_9-doped Ba_(0.6)Sr_(0.4)TiO_3 microwave composite ceramics

BaTi4O9-doped Ba0.6Sr0.4TiO3 (BST) composite ceramics were prepared by the conventional solid-state reaction and their structure, dielectric nonlinear characteristics and microwave dielectric properties were investigated. The secondary phase of the orthorhombic structure Ba4Ti13O30 is formed among BST composite ceramics with the increase of BaTi4O9. At the same time, a duplex or bimodal grains size distribution shows fine grains in a coarse grain matrix. The degree of frequency dispersion of dielectric permittivity below Tm is increased initially and then decreased with respect to BaTi4O9. As the BaTi4O9 content increases, the tunability of composite ceramics decreases, while the Q value increases. Inter-estingly, 70 wt% BaTi4O9-doped BST has a tunability ~4.0% (under 30 kV/cm biasing) versus a permit- tivity ~68 and quality factor ~134.1 (at ~3.2 GHz).     

金属间化合物/陶瓷复合材料的制备技术

简要介绍了金属间化合物／陶瓷复合材料的制备方法、基本原理以及发展现状，并对其未来的发展方向作了展望。     

ZrN／TiN复合涂层刀具的制备及切削性能

采用中频磁控溅射和电弧离子镀2种方法组合，在YG6硬质合金基体上沉积ZrN／TiN复合涂层．研究了复合涂层刀具的制备工艺，并对复合涂层刀具的性能参数进行了测试．通过切削试验研究了ZrN／TiN涂层对硬质舍金刀具切削性能的影响，并与未涂层刀具的切削效果做了对比．结果表明：ZrN／TiN涂层提高了硬质合金刀具的硬度，降低了涂层刀具的切削力，提高了涂层刀具的耐磨损能力．     

纳米TiC对Si3N4基复合陶瓷材料性能和微观结构的影响

用热压法制备了纳米TiC增韧补强的Si₃N₄基复合陶瓷材料,研究了不同TiC含量对复合陶瓷材料力学性能与微观结构的影响.结果表明：纳米TiC颗粒的添加对复合材料的力学性能的提高是有利的,当纳米TiC的质量分数为15%时,复合材料具备较优的力学性能,其抗弯强度、断裂韧性、HV硬度分别达到895MPa,8.03MPa.m1/2,15.06GPa;不同尺寸的Si₃N₄晶粒形成双峰结构,有利于复合材料性能的提高;其断裂机制为沿晶断裂和穿晶断裂的混合类型.     

ZrN/TiN复合涂层刀具的制备及切削性能

采用中频磁控溅射和电弧离子镀2种方法组合,在YG6硬质合金基体上沉积ZrN/TiN复合涂层.研究了复合涂层刀具的制备工艺,并对复合涂层刀具的性能参数进行了测试.通过切削试验研究了ZrN/TiN涂层对硬质合金刀具切削性能的影响,并与未涂层刀具的切削效果做了对比.结果表明：ZrN/TiN涂层提高了硬质合金刀具的硬度,降低了涂层刀具的切削力,提高了涂层刀具的耐磨损能力.     

电弧离子镀TiN/TiAlN复合涂层摩擦磨损性能研究

利用阴极电弧离子镀技术,在硬质合金基体上制得5层和20层TiN/TiAlN复合涂层.研究表明,这两种涂层均为典型的B1-NaCl面心立方结构,且均呈(200)择优取向.两种涂层表面光滑平整,粗糙度分别为0.32和0.11,硬度为1 470HV和2 000HV .20层复合涂层的摩擦系数和比磨损率低于5层,表明增加复合层数有利于提高涂层的耐磨损性能,涂层的磨损机理为磨粒磨损.     

Influence of alumina addition on the optical property of zirconia/alumina composite dental ceramics

The influence of various alumina additions on the optical property of zirconia/alumina composite ceramics was investigated. The relative sintered densities, transmittances, color and the microstructure of the composite ceramics were studied. The experimental results showed that the relative sintered densities and transmittances decreased with alumina addition. The lightness increased obviously but the chroma change was small. Pure zirconia nanopowders sintered densely could obtain the relatively high transmittance, while the transmittance and the lightness of slight addition changed significantly. The zirconia/alumina composite ceramics with alumina addition less than 7.5wt% could achieve the relatively stable and reliable optical properties.     

直流PCVD TiN膜针孔率的研究

用铁氰化钾贴纸法研究了PCVD(Plasma CVD)TiN膜中针孔率与沉积温度、样品表面粗糙度和膜厚度的关系。发现TiN膜薄时,针孔率高,针孔直径多数在1～3μm;TiN膜厚时,针孔急剧减少,针孔直径均在3.5～6μm,表明小直径的针孔在TiN生长中逐渐消失。TiN膜厚达到8～10μm时,仍有针孔存在。扫描电镜观察表明:形成针孔的主要原因是表面存在杂质(或污物)和孔洞缺陷。     

Toughening mechanism of lined Al2O3-ZrO2 multiphase ceramics in SHS composite pipes

1. IntroductionEngineering ceramics is known worldwide becauseof its high operating temperature, corrosion resistanceand wear resistance. The ceramics-lined compositepipes are widely researched for their extensiveprospects in engineering application. The …     

Effect of nano-ZrO2 on microstructure and thermal shock behaviour of Al2O3/SiC composite ceramics used in solar thermal power

The Al2O3-ZrO2(3Y)-SiC composite ceramics used in solar thermal power were prepared by micrometric Al2O3,nano-ZrO2 and SiC powders under the condition of pressureless sintering.The bulk density and bending strength of samples with 10vol% nano-ZrO2 sintered at 1480℃ were 3.222 g/cm3 and 160.4MPa,respectively.The bending strength of samples after 7 times thermal shock tests (quenching from 1000℃ to 25℃ in air medium) is 132.0MPa,loss rate of bending strength is only 17%.The effect of nano-ZrO2 content on the microstructure and performance of Al2O3-ZrO2(3Y)-SiC composite ceramic was investigated.The experimental results show that the bending strength of samples with above 10vol% nano-ZrO2 content has decreased,because the volume expansion resulting from t-ZrO2 to m-ZrO2 phase transformation is excessive;Adding proper nano-ZrO2 would be contributed to improve the thermal shock resistance of the composite ceramics.The Al2O3-ZrO2(3Y)-SiC composite ceramic has promising potential application in solar thermal power.     

HA-ZrO2生物复合材料的制备

首先以H3PO4和Ca(OH)2为主要原料利用湿化学方法合成了结晶良好的羟基磷灰石粉体(HA),在该粉体中分别引入15%、20%和25wt%的m-ZrO2粉体,经成型后分别在900℃、1 000℃、1 100℃和1 200℃温度下煅烧1h,详细研究ZrO2含量和烧结温度对该复合材料物相及体积密度的影响规律.结果表明:随着烧成温度的升高,该复合材料的体积密度呈上升趋势,当温度为1 000℃时达到最大值,当温度进一步升高时,体积密度下降.而复合材料中的HA相随温度的升高而不断降低,当温度超过1 000℃时该趋势更加明显.随ZrO2的引入材料体积密度有一定提高,但当ZrO2含量超过20%时,其体积密度有所降低,当ZrO2含量为20%时,杂质含量最低.