Wear mechanism of electrodeposited amorphous Ni-Fe-P alloys

1　INTRODUCTIONAmorphousalloysarecharacterizedbyhighwearandcorrosionresistance ,togetherwithmanyspecificphysicalproperties[1,2 ] .Theyhavebeenusedasfunc tionalmaterialsinmanyfieldsextensively .Theamor phousNi Palloyhasbeenappliedtoautomobile[3] ,aircraft,computer ,electronics ,food processing ,petroleum ,andsoon[4 ] .Electrodepositionorelectrolessplatingisoneofthemostsimple ,convenientandeconomicmethodstoobtainvariousamorphousalloys .Themostattractiveamorphousalloysconsistoftheelementsof…     

FeCuMoSiB合金穆斯堡尔谱研究

用Ｘ射线衍射技术和穆斯堡尔谱技术，研究了Ｆｅ７３．５ＣｕＭｏ３Ｓｉ１３．５Ｂ９合金的结构和超业细相互作用。该合金的相组成为α－Ｆｅ（Ｓｉ）纳米晶和边界相即五余非晶相。典型纳米晶状态下的穆斯堡尔谱由５条亚谱构成，其中４条亚谱为６峰谱，对应α－Ｆｅ（Ｓｉ）相中的４种不同环境的Ｆｅ原子。另１条亚谱对应边界处的非晶相，研究了非晶带材经５００－６００℃不同温度晶化处理后的穆斯堡尔谱特性。     

蒸发法制备Ni－Ti纳米非晶合金粒子

采用气相蒸发法制备纳米量级的Ｎｉ－Ｔｉ非晶合金粒子，研究了各种因素对Ｎｉ－Ｔｉ纳米非晶合金粒子形成的影响，并用透射电子显微镜，高分辨电子显微镜，Ｘ射线衍射仪和能谱等多种手段对纳米非晶合金粒子进行了表征．结果表明，当粒子成分在共晶区Ｎｉ（４０）Ｔｉ（６０）附近时，容易形成非晶；较低惰性气体压力和较高蒸发温度有利于Ｎｉ－Ｔｉ纳米非晶粒子的形成．     

Fe－Dy非晶膜晶化过程中结构及磁性变化

用真空双源蒸镀法在ＮａＣｌ和Ｓｉ单晶衬底上制备Ｆｅ，Ｄｙ成分调制多层膜．研究了非晶膜晶化过程，等温退火后多层膜结构及磁性变化。结果表明，在２００℃以下退火，其沉积态非晶和成分调制结构几乎不变；３００℃开始晶化，首先出现Ｆｅ晶核，随温度升高，Ｆｅ，Ｄｙ逐步晶化，６００℃全部形成晶态ｂｃｃ－Ｆｅ和ｈｃｐ－Ｄｙ．饱和磁化强度Ｍｓ对非晶Ｆｅ，Ｄｙ膜晶化时Ｆｅ晶核的形成十分散感，而只有Ｆｅ晶粒的长大才导致矫顽力Ｈｃ增加．     

Influences of Ta, Nb, or Mo additions in Zr-based bulk metallic glasses on microstructure and thermal properties

The master-alloy ingots for casting bulk metallic glasses are routinely prepared by arc melting a mixture of pure elements. This paper addresses the difficulty in achieving complete and homogeneous melting of refractory component additions in Zr-based BMGs using the above procedure, and its influences on the microstructure and thermal behavior of alloys.     

Performance of positive and negative electrodes in amorphous manganese oxide supercapacitor

Using potassium permanganate and acetic manganese as the reactants, amorphous manganese oxide was prepared with mechanochemical method. XRD was used for microstructure characterization, while cyclic voltammetry and constant current charge-discharge were used for electrochemical performance testing. The positive electrode （PE） and negative electrode （NE） were investigated respectively in amorphous manganese oxide supercapacitor, aiming to find their different performances in charging-discharging. The results show that the crystalline structure is destroyed in both the PE and NE material during charge-discharge process. Thereinto, the NE suffers a bit more seriously. When cycling, the PE potential scope diminishes while the NE potential scope enlarges. The increased inner resistance makes the NE curves almost bended to be a right angle, but not the PE curves. The cell＇s equivalent series resistance （ESR） is more dependent on the NE, and the capacitance is mainly determined by the rapid descent of the NE potential range. The capacitances of the NE are highly rate-dependent, decreasing from 121.3 to 53.1 F/g, by 56.2%, over the range of 5-25 mV/s. However, the PE appears to be weakly dependent and its capacitance is only dropped by 22.1%.     

微量碳对淬态Fe－Si－B非晶丝表面层结构及脆性的影响

用旋转水中熔融金属纺丝法制备了Ｆｅ－Ｓｉ－Ｂ非晶金属丝。拉伸和弯折性能表明，当合金中杂质碳原子分数含量≥０．２％时，制备态（淬态）非晶丝发生脆化。电子探针、Ａｕｇｅｒ能谱分析与透射电镜观察发现，非晶丝表面具有大约１５０－３００ｎｍ宽的富碳层且包含Ｆｅ＿（２３）（Ｃ，Ｂ）＿６相。该相是Ｆｅ－Ｓｉ－Ｂ非晶丝脆化的原因。     

基于铁基非晶薄带巨磁阻抗效应的位移传感器

利用铁基非晶薄带的特性研制了一种新型的非接触位移传感器.介绍了铁基非晶薄带的磁敏特性、处理方法及位移传感器电路的设计,并对传感器的特性进行了测试.结果显示:所设计的位移传感器重复性好,最大偏差为0.2973％、迟滞小,最大为0.6526％.     

Thin‐film transistor mobility limits considerations

The mobility limiting scattering mechanisms for amorphous semiconductors and polar polycrystalline semiconductors are studied in the context of developing new high‐performance thin‐film transistor (TFT) channel layer materials for large‐area electronics. A physics‐based model for carrier transport in an amorphous semiconductor is developed to estimate the mobility limits of amorphous semiconductor TFTs. The model involves band tail state trapping of a diffusive mobility. Simulation reveals a strong dependence on the band tail density of states. This consideration makes it difficult to realize a high‐performance p‐type oxide TFT. A polar crystalline semiconductor may offer a higher mobility but is fundamentally limited by polar optical phonon scattering. Any crystalline TFT channel layer for practical large‐area applications will not be a single crystal but polycrystalline, and therefore, grain size and grain boundary‐dependent scattering will further degrade the transport properties.