朱平
,
林忠钦
,
陈关龙
,
池田清彦
材料研究学报
采用断裂力学中的四点弯曲试验法, 研究并预测了氧化铝和氧化锆陶瓷材料在大气和水环境中的循环疲劳破坏特性. 结果表明, 在相同的应力条件下,氧化铝和氧化锆陶瓷材料, 尤其是氧化锆陶瓷, 在水环境中的疲劳寿命比大气中的低.通过将预测结果与实验结果比较和对人造股关节的应用,验证了这种疲劳寿命预测方法的有效性和适用性.
关键词:
无机非金属材料
,
ceramics
,
mater environment
,
cyclic loading
Zhijun LIN
,
Meishuan LI
,
Yanchun ZHOU
,
null
,
null
材料科学技术（英）
Layered ternary ceramics represent a new class of solids that combine the merits of both metals and ceramics. These unique properties are strongly related to their layered crystal structures and microstructures. The combination of atomic-resolution Z-contrast scanning transmission electron microscopy (STEM) and transmission electron microscopy (TEM), selected area electron diffraction (SAED), convergent beam electron diffraction (CBED) represents a powerful method to link microstructures of materials to macroscopic properties, allowing layered ternary ceramics to be investigated in an unprecedented detail. Microstructural information obtained using TEM is useful in understanding the formation mechanism, layered stacking characteristics, and defect structures for layered ternary ceramics down to atomic-scale level; and thus provides insight into understanding the ``Processing-Structure-Property" relationship of layered ternary ceramics. Transmission electron microscopic characterizations of layered ternary ceramics in Ti-Si-C, Ti-Al-C, Cr-Al-C, Zr-Al-C, Ta-Al-C and Ti-Al-N systems are reviewed.
关键词:
Layered ternary ceramics
,
ternary
,
ceramics
,
MAX
,
phase
,
TEM
,
S
Journal of the American Ceramic Society
Carbon-silicon carbide (C-SiC) graded-matrix composites were prepared via chemical vapor infiltration with carbon and SiC codeposition from methyltrichlorosilane (CH3SiCl3), acetylene (C2H2), argon, and hydrogen, The graded-matrix composites were prepared by gradually varying the source gases, from C2H2 to CH3SiCl3, in a semicontinuous process. Oxidation resistance, wear, and mechanical tests were conducted, and the microstructure was observed via optical microscopy, electron probe microanalysis, transmission electron microscopy, and scanning electron microscopy, The results show that this material seems to be macroscopically homogeneous, as an integral part of the entire material; however, microscopic examination shows a gradient variation of the matrix sheaths around each fiber. The oxidation resistance of the material is significantly superior to that of a C/C material, which is a promising thermostructural material, because of its lour density, good mechanical properties, and good resistance to oxidation.
关键词:
ceramics
Japanese Journal of Applied Physics Part 1-Regular Papers Brief Communications & Review Papers
The temperature, frequency, and voltage dependences of the dielectric properties of 0.93Pb(Fe(1/2)Nb(1/2))O(3)-0.07PbTiO(3) single crystals were investigated in the temperature range of 100-300 K. An anisotropic colossal dielectric response was observed when the probe of the AC field was along the [100] and [111] directions. One relaxation was detected in the [100] direction, while two relaxations were detected in the [111] direction. The activation energies of the relaxations are in the range of 0.155-0.190 eV, indicating that the relaxations are probably caused by 3d electrons hopping between Fe(2+) and Fe(3+). The origin of the anisotropic colossal dielectric response can be explained by a "two-hopping path'' model. (C) 2011 The Japan Society of Applied Physics
关键词:
ceramics
Journal of Applied Physics
The electronic structure and properties of layered ceramic Ti3GeC2 have been examined by means of ab initio linear combination of atomic orbital calculations. The calculated band structure shows Ti3GeC2 to be strongly metallic with high densities of states at the Fermi level. The electrical conductivity is dominated by a Ti (2) 3d state with less contribution from Ti (1) 3d, Ge 4p, and C 2p states. The major factors governing the electronic properties are pd hybridization from Ti 3d, Ge 4p, and C 2p states, and p-d bonding stabilizes the structure. (C) 1999 American Institute of Physics. [S0021-8979(99)02015-0].
关键词:
ceramics
DAI Zurong LI Baocheng Taiyuan Institute of Mechanical Engineering
,
Taiyuan
,
ChinaWU Houzheng CHEN Yuru LIU Wenxi Tianjin University
,
Tianjin
,
China
金属学报(英文版)
A dynamic process of the martensitic transformation in(Y,Mg)-PSZ ceramics was observed in situ using TEM.Under the effect of contact stress between tetragonal(t)-ZrO_2 precipi- tates,a group of substructural martensite variants may occur priorly and then another one was induced by the elastic strain relaxation,both form(100)_m twins further.In addition,the crystallography of the martensitic transformation was also discussed.
关键词:
ceramics
,
null
,
null
余祖孝
,
郝世雄
,
罗宏
,
将志鹏
材料保护
陶瓷表面金属化处理的传统镀银工艺存在工艺复杂、设备投资大、成本高、耐焊及耐磨性不足等缺点,使用化学镀铜技术可以很好地解决上述问题.用电化学等方法,研究了添加剂亚铁氰化钾、2,2'-联吡啶和L-精氨酸对陶瓷化学镀铜镀液的沉积速度与稳定性、镀层的耐腐蚀性、导电性及结合力的影响.结果表明:用4%AgNO_3作为活化荆,代替价格昂贵的PdCl_2,效果较好.陶瓷镀铜最佳配方和工艺为:15 g/L硫酸铜,10 mL/ L甲醛,40 g/L酒石酸钾钠,pH值12.6,室温,施镀时间1 h,无搅拌.添加剂最佳使用量分别为:5mg/L亚铁氰化钾;5 mg/L 2,2'-联吡啶;10 mg/L L-精氨酸以及二元复合添加剂5 mg/L 2,2'-联吡啶+10mg/L L-精氨酸.所得陶瓷镀铜层呈现光亮的淡粉红色.
关键词:
陶瓷
,
化学镀铜
,
活化剂
,
添加剂
,
亚铁氰化钾
,
2,2'-联吡啶
,
L-精氨酸
,
性能
鲁圣国
,
唐新桂
,
伍尚华
,
ZHANG Qi-Ming
无机材料学报
doi:10.3724/SP.J.1077.2014.13310
电卡效应在实现高效率和小尺寸的固态制冷器件方面具有巨大的潜力.本文介绍了获得大电卡效应的热力学原理,评述了近年来电卡效应的实验表征工作,发展了一种直接测量电卡效应熵变或温度变化的方法.结果表明:驰豫型铁电体聚合物和一级相变聚合物材料表现出较大的电卡效应.综合最近在BaTiO3单晶和多层陶瓷电容器的工作,以及铁电制冷器件的尝试,电卡效应表现出诱人的应用前景.
关键词:
铁电材料
,
单晶
,
陶瓷
,
聚合物
,
电卡效应
,
制冷器件
,
综述
陈杰
,
徐佳楠
,
周阳
,
张萍
,
杨为中
钢铁钒钛
doi:10.7513/j.issn.1004-7638.2016.05.015
利用工业废料钒钛渣为原料制备日用陶瓷,在原料球磨时间10 min,烧结温度1 100℃等较佳工艺条件下,研究MgO添加剂对陶瓷的烧失率、线收缩、吸水率、气孔率、断裂模数等的影响.采用XRD、SEM研究样品的晶相组成和显微结构.试验结果表明:添加0.6％ MgO能显著提高钒钛废渣陶瓷的断裂模数,降低吸水率和气孔率;陶瓷主晶相为石英、钙长石、镁铬尖晶石等.添加MgO可提高钒钛废渣的用量,实现废弃资源再利用.
关键词:
钒钛废渣
,
陶瓷
,
球磨时间
,
MgO
,
MgCr2O4
,
线收缩
,
断裂模数
