热处理对YBa_2Cu_3O_（7－x）的J_c影响

论述了热处理温度、时间、气氛对ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－ｘ）的组织和Ｊ＿ｃ的影响，在氧气氛下热处理ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－ｘ）的效果比在空气下效果好．最佳热处理条件为：８７０℃，３小时，２个大气压纯氧条件下，Ｊ＿ｃ值可达１１４０Ａ／ｃｍ￣２。     

YBa_2Cu_3O_7-x-Ni超导带材的成型工艺研究

本文论述 YBa_2Cu_3O_(7-X)粉末在镍带上成型的工艺,YBa_2Cu_3O_(7-X)—Ni 在820℃保温约3分钟后进行轧制,通过轧制形成的 YBa_2Cu_3O_(7-X)—Ni 复合带没有超导电性,经过热处理后(820℃～950℃),复合带具有超导电性,Tc>77K.Jc 值为0.1～390A/cm~2.     

热加工和热处理对YBa_2Cu_3O_(7-x)超导带材的相结构和氧的影响研究

本文论述了YBa_2Cu_3O_(7-x)超导带材热加工和热处理中相结构和氧的变化,热轧后的带材为正交相和四方相,在热处理加热时,超导带材首先吸氧,当加热到450℃时又失氧,在冷却过程中从900℃到450℃吸氧较快,450℃以后,吸氧逐渐平衡。高J_c的超导带中J_c与氧含量不呈线性关系,高J_c的带材经X射线分析二类应力较大。     

STUDY ON PREPARATION OF YBa_2Cu_3O_(7-x) ULTRAFINE POWDERS BY SOL-GEL PROCESS

The ultrafine powders of YBa_2Cu_3O_(7-x) withthe size of 100nm were synthesized by Sol-Gel process using cit-rate as complex and ammonium hydroxide to adjust pH of solu-tion. The process of Sol formation and Gel polymerization ofYBa_2Cu_3O_(7-x) in the Sol-Gel synthetic reaction has bee studied.The particle size,pruity,sintering activity and superconductingproperties of YBa_2Cu_3O_(7-x)prepared by Sol-Gel method are betterthan by solid state reaction.     

YBa_2Cu_3O_(7-δ)超导体比热的测量

用绝热法测量了ＹＢａ＿２Ｃｕ＿３Ｏ＿（７－δ）高温超导体的比热，介绍了测量方法和测量装置，并给出了在液氦７７～１１０Ｋ温度区所测比热的结果．     

Bi_(1,7-X)Pb_(0.3)Sb_xSr_2Ca_2Cu_3O_(10)的制备及超导电性研究

本文采用差热分析研究了Bi_(1,7-x)Pb_(0.3)Sb_xSr_2Ca_2Cu_3O_(10)(x=0.05;0.10;0.15;0.20)系统的烧结工艺,研究了元素Sb的置换对该体系超导电性的影响,少量Sb的置换有利于110K相的快速生成,减少反应时间,同时,由于Sb~(3+)的离子半径小于Bi~(3+),置换量过大则会导致大量的杂相生成而降低体系的T_c.     

LOW TEMPERATURE MAGNETIC FORCE MICROSCOPY STUDY OF VORTEX IN A YBa_2Cu_3O_(7-x) THIN FILM

A low temperature magnetic forc micro-scope for the study of high temperature superconductor isdeveloped. It has been applied to spatially resolve singlevortices at low temperature (77K) in a YBa_2Cu_3,O_(7-x). thinfilm deposited by laser ablation on a NdGaO_3 substrate.The images of disordered vortex arrangements are obtained. The movement of single vortices after a contactmode scanning of the detecting tip over the thin film sur-face is observed. The reason for the movement is dis-cussed.     

Ca替代Y对YBa_2Cu_3O_(7-δ)超导电性的影响

用固相反应方法制备了Y_(1-x)Ca_xBa_2Cu_3O_y(x=0.0,0.02,0.05,0.10,0.15,0.20,0.50)系列样品,发现超导转变温度随x增加而呈线性下降。粉末x-射线衍射结果表明,在x≤0.15范围内,体系呈现出很好的正交单相性,晶格参数无明显变化。用碘滴定方法测量了体系的氧含量,发现随着x的增加,Cu的平均价态降低,氧含量减少。把上述结果同Y_(1-x)Pr_xBa_2Cu_3O_y作比较,表明氧含量和Cu的平均价态均不是决定Tc的直接因素。讨论了氧含量改变的可能位置和引起超导电性发生变化的原因。     

Sol－Gel法制备YBa_2Cu_3O_（7－x）超细粉末研究

用柠檬酸盐作螯合剂，用氨水调节溶液的酸度，通过Ｓｏｌ－Ｇｅｌ转变制得了粒径为１００ｎｍ大小的ＹＢａ２Ｃｕ３Ｏ（７－ｘ）超细粉末，对ＹＢａ２Ｃｕ３Ｏ（７－ｘ）在合成反应中溶胶的形成和凝胶聚合过程进行了研究和探讨。Ｓｏｌ－Ｇｅｌ法制得的ＹＢａ２Ｃｕ３Ｏ（７－ｘ）超细粉末在粒度、纯度、烧结特性和超导性能上，均优于固态反应合成方法。     

YBa_2Cu_3O_（7－δ）超导陶瓷螺旋谐振器

用ＹＢａ２Ｃｕ３Ｏ（７－δ）超导陶瓷裸线绕制了一定弹性和强度的螺旋谐振器内导体，整个ＹＢａ２Ｃｕ３Ｏ（７－δ）螺旋是导通和超导的。对比测试了室温和液氮温区下超导螺旋和同样尺寸Ｃｕ螺旋谐振器的品质因数（Ｑ），液氮温区（７７Ｋ、ｌ００ＭＨｚ）下，前者的Ｑ值比后者高３倍，初步显示了ＹＢａ２Ｃｕ２Ｏ（７－δ）高温超导体在这一领域应用的优越性。     

Magnetism Regulation of (In_(1-x)Fe_x)_2O_3 Semiconductors Prepared by Sol-gel Method

Fe doped In2O3 samples (In1-xFex)2O3 (x=0, 0.05, 0.1, 0.2 and 0.3) on glass substrate were prepared by sol-gel method. The XRD results demonstrate that the solubility of Fe ions in In2O3 matrix is around 20%, above which impurity phase can be observed. The transmittance of the samples with x=0, 0.05, 0.1 and 0.2 are above 80% in the visible region while the transimittance of the glass is 90%. The transmittance curves slightly red-shifts as x increasing. All of the samples except x=0 are ferromagnetic at roo...     

x变化对Nd1＋xBa2—xCu3Oy结构与性能的影响

用X-ray衍射方法研究了不同x值对烧结Nd1 xBa2-xCu3Oy样品衍射图谱的影响规律，对不同Nd422相加，入量的烧结及区域熔炼Nd1 xBa2-xCu3Oy超导体进行了X－ray粉末衍射并测量了各样品的Jc值，对比结果表明，Nd422相的加入会使Nd1 xBa2-xCu3Oy中的x值增大并影响Jc。对取代与Nd1 xBa2-xCu3Oy超导体性能的关系做了初步的探讨，认为，取代的作用是双重的，Nd123之所以具有很好的Jc-B特征，正是Nd-Ba取代的作用使然；适量的取代对改善样品的性能是有好处的，因此研究的目标应是寻找最佳的取代量。     

添加Y_2O_3的AlN陶瓷的高温强度

以Y_2O_3为烧结助剂,采用热压烧结法制备了AlN陶瓷。采用X—ray、SEM、EPA测试了样品的结构,确定了样品的相组成与相分布。探讨了抗弯强度与温度、抗弯强度与1300℃空气中氧化时间的关系。结果表明,在低于1300℃时强度随温度升高缓慢下降,在1300～1500℃时急剧下降。在1300℃空气中样品产生氧化,强度随氧化时间的增加不断下降。本文讨论了AlN陶瓷在不同温度范围及长时间在1300℃空气中氧化后的断裂机理。