双喷嘴快淬法制得的非晶/晶体Fe_(55)Ni_(20)Cu_5P_(10)Si_5B_5

正Krzysztof Ziewiec等人采用双喷嘴快淬法制造Fe_(40)Ni_(40)P_(10)Si_5B_5和Fe_(70)Cu_(10)P_(10)Si_5B_5合金混合物,是两种液相不互溶的合金。根据Fe_(70)Cu_(10)P_(10)Si_5B_5合金试验,选择适宜快淬温度。双喷嘴快淬制得Fe55Ni20-Cu5P10Si5B5合金,晶体沿非晶带和非晶/晶体的快淬方向排列。Fe_(55)Ni_(20)Cu_5P_(10)Si_5B_5合金由于加热而晶化,析出带状微结构。双喷嘴得到的非晶相比单一喷嘴快淬法多。对双喷嘴快淬法制得的合金的结构、相成分     

Cr,Cu,Co对Fe—Si—B非晶合金磁致伸缩系数的影响

本文报道了Fe_(80-x)Cr_xSi_5B_(15),Fe_(80-x)Cr_xC_5B_(15),Fe_(80-x)Cu_xSi_5B_(15)和(Fe_(1-x)Co_x)_(32)Cu_(0.4)Si_(4.4)B_(13.2)四系列非晶合金在室温下的饱和磁致伸缩系数λs随成分x的变化关系,讨论了C,Si,Cr,Cu,Co原子对磁致伸缩系数的影响。发现少量Cu,Co的加入大大提高了非晶合金的λs。特别是(Fe_(1-x)Co_x)_(82)Cu_(0.4)Si_(4.4)B_(13.2)系列中当x=0.02时峰值λs=70×10~(-6)。     

Fe基非晶合金的晶化及其在NaCl溶液中的电化学腐蚀行为

采用单辊甩带法制备出完全非晶态的Fe_(78)Si_(13)B_9和Fe_(73.5)Si_(13.5)B_9Nb_3Cu_1薄带,并利用非晶晶化退火法制备非晶和纳米晶双相合金Fe_(73.5)Si_(13.5)B_9Nb_3Cu_1薄带.利用X射线衍射仪和示差扫描量热计对该非晶薄带的非晶特性及其晶化过程进行研究,并用电化学极化曲线的方法和电化学阻抗技术对比研究非晶Fe_(78)Si_(13)B_9和双相合金Fe_(73.5)Si_(13.5)B_9Nb_3Cu_1在1 mol/L NaCl溶液里的电化学腐蚀行为,用SEM对极化测试后的试样形貌进行观察;同时还研究不同的热处理温度对材料的结构及在1 mol/L NaCl溶液里耐腐蚀性能的影响.结果表明:该非晶薄带的晶化过程分为两步;双相合金比非晶合金的耐腐蚀性要好;随着热处理温度升高,非晶合金和双相合金的耐腐蚀性能都得到提高.     

Finemet型纳米晶软磁合金的双团簇特征与成分优化

基于Finemet合金的成分及其非晶前驱体的晶化特征,提出了Finemet型合金的"双团簇"结构模型和团簇式成分,即Finemet合金的非晶前驱体可看作由2类团簇结构构成:一种为基于a-Fe(Si)有序固溶体(例如Fe_3Si相)的[Si-Fe_(14)](Cu_(1/13)Si_(12/13))_3弱稳定团簇结构;另一种为对应于Fe-B-Si-Nb系块体非晶合金的[(Si,B)-B_2(Fe,Nb)_8]Fe强稳定团簇结构。将2种团簇成分式按等比例混合,设计并制备了多个新成分合金。热分析和磁性测量结果表明,所有成分的非晶样品均显示多峰晶化特征,其中,[(Si_(0.8)B_(0.2))-B_2Fe_(7.2)Nb_(0.8)]Fe+[Si-Fe_(14)](Cu_(1/13)Si_(12/13))_3(即Fe_(74)B_(7.33)Si_(15.23)Nb_(2.67)Cu_(0.77))非晶两晶化峰的峰间距(ΔT_p=T_(p2)-T_(p1))最大,约为192 K。该非晶样品在813 K等温退火60 min后获得典型的纳米晶/非晶复相结构,其饱和磁化强度B_s约为1.26 T,矫顽力H_c约为0.5 A/m,1 k Hz下的有效磁导率m_e约为8.5×10~5。新成分纳米晶合金的综合软磁性能均优于典型成分为Fe_(73.5)Si_(13.5)B_9Cu_1Nb_3的已有Finemet纳米晶合金。     

非晶合金Fe_(80-x)Cu_xSi_5B_(15)和(Fe_(1-y)Co_y)_(82)Cu_(0.4)Si_(4.4)B_(13.2)的晶化行为

用X射线衍射、吸收和内转换电子发射Mossbauer谱技术,研究了Fe_(80-x)Cu_xSi_5B_(15)和(Fe_(1-y)Co_y)_(82)Cu_(0.4)Si_(4.4)B_(13.2)两系列非晶合金的晶化行为.单辊急冷法制备的非晶带,晶化首先从贴辊面开始,晶化产物为α-Fe相.在Fe_(80)Si_5B_(15)非晶合金中以少量Cu替代Fe可以提高晶化温度.我们的结果表明,过渡金属的含量超过80at.-%,如增加到82at.-%,晶化温度就明显降低.所研究两系列含Si的铁基非晶合金在400—450℃范围内退火2h,都出现α-Fe,Fe_3B和Fe_2B三种晶态相共存状态.退火温度再升高,亚稳相Fe_3B逐渐转变为Fe_2B和α-Fe.     

辊速及晶化工艺对(Nd, Pr)13Fe80Nb1B6快淬薄带组织和矫顽力的影响

用熔体快淬法制备(Nd,Pr)_(13)Fe_(80)Nb_1B_6快淬薄带并晶化处理,研究辊速和晶化条件对其组织和矫顽力的影响.结果表明,在10～20、25和35 m/s分别得到纳米晶、部分非晶和完全非晶薄带,且在18 m/s制备的薄带有较好的c轴各向异性.快淬态薄带的矫顽力随辊速(10～25 m/s)的增大而增加.非晶薄带晶化后由(Nd,Pr)_2Fe_(14)B相和富稀土相组成,且完全非晶薄带晶化后比部分非晶薄带晶化后的矫顽力要高,这是由于前者比后者具有更均匀的微结构造成的.非晶薄带晶化后矫顽力最大为1616 kA/m,高的矫顽力与添加Pr和Nb有关.     

硅含量对FeBSi非晶合金性能及晶化过程的影响

用真空感应炉冶炼母材.原料用纯度为90%的B粉、纯铁和单晶硅.用双辊法制成宽度3mm,厚度0.04mm的非晶合金带材.其成分为Fe_(82)B_(18-x)Si_x(x=2,4,6,8,10)以及Fe_(80)B_(20).饱和磁化强度σ、晶化温度Tc、居里温度Tθ、磁致伸缩λs、玻璃转化温度Tg随硅含量的变化而变化,合金的玻璃化温度随硅含量的增加而升高得较快.将上述的非晶合金在250,300,350,400,450,500,600,700℃保温20分钟后淬     

磁场退火对纳米晶合金软磁性能的影响

利用真空退火,将非晶合金纳米晶化,并通过XRD试验手段验证了其纳米晶结构,研究了磁场退火对纳米晶合金软磁性能的影响。研究表明,在外加磁场条件下,对Fe_(74.5)Cu_1Nb_2Si_(13.5)B_9、(Fe_(0.5)Co_(0.5))_(73.5)Cu_1Nb_3Si_(13.5)B_9和Ni_(25)(Fe_(0.5)Co_(0.5))_(48.5)Cu_1Nb_3Si_(13.5)B_9纳米晶合金进行二次热处理,可以不同程度地减小合金的饱和磁致伸缩程度。然而,磁场退火后纳米晶合金在较低温度下的初始磁导率出现了不同程度的降低,原因可以归结为:在磁场退火的过程中,感生出的单轴各向异性增加了合金总的各项异性。     

Fe_(80)Si_(8.5)B_xP_(9.5-x)Cu_2非晶形成能力与磁性能研究

铁基非晶拥有优异的软磁性能,B元素的加入对非晶合金具有重要意义。结果表明:Fe_(80)Si_(8.5)B_xP_(9.5-x)Cu_2(x=0,1,3,6,8)中随B元素含量的增加,其非晶形成能力增加,热稳定性增加。同时也提高了Fe_(80)Si_(8.5)B_xP_(9.5-x)Cu_2非晶合金的软磁性能,当x=8时,其饱和磁化强度(M_s)达234.94emu/g,磁矫顽力为20.7Oe。     

表面处理和温度对非晶/纳米晶磁芯软磁性能的影响

用宽20 mm、厚25μm的Fe_(73.5)Cu_1Nb_3Si_(13.5)B_9非晶带材绕制成环形磁芯,再经550℃×100 min晶化退火处理制成非晶/纳米晶磁芯。研究了环氧树脂封装和测试温度对其软磁性能的影响。结果表明,与环氧树脂封装前相比,封装后的起始磁导率、最大磁导率、饱和磁感应强度和电感减小;矫顽力、磁滞损耗和剩磁增大;磁化曲线和磁滞回线基本上重合。随测试温度的升高,环氧树脂封装前后的起始磁导率和电感均呈先增大后减小的趋势;饱和磁感应强度均减小;矫顽力均增大。     

纳米晶(FeCo)78Nb6B15Cu1合金晶化过程及其磁特性研究

采用熔体快淬法制备(FeCo)78Nb6B15Cu1非晶薄带,通过DSC测试薄带的晶化特性,并据此在400,500,700和750℃进行1h退火处理。用XRD和SEM分析薄带在不同退火温度下的晶化行为,并用VSM测试薄带与粉体的静态磁参数。结果表明:对于固定成分的Hitperm合金,选择合适的退火温度,可控制晶粒大小和晶相比例。由于晶粒表面无序磁矩含量的变化,导致材料比饱和磁化强度发生变化,同时更小的纳米晶粒对降低矫顽力有利。由于淬态引入的微量结晶,薄带存在表面晶化现象,这在一定程度上会恶化材料的静态磁特性。     

Nd60Fe30M10（M=Al，Si，Ga）系非晶永磁的性能与组织结构

采用真空快淬设备以辊速5m／s、10m／s、15m／s、20m／s、30m／s制备了Nd60Fe30M10（M=Al,Si,Ga）系的“非晶带”,研究了制备速度对“非晶带”永磁性能和结构的影响。实验结果表明：Nd60Fe30Si10和Nd60Fe30Ga10同经典合金Nd40Fe30Al10一样,也显示出非晶永磁性能,并且比相同条件下制备的Nd60Fe30Al10“非晶带”的永磁性能更好;三种“非晶带”的矫顽力随辊速的降低而提高。对Nd60Fe30Al10“非晶带”的TEM分析表明,以30m／s辊速制备的“非晶带”,有2～5nm的析出物弥散分布在非晶基体上;而以5m／s辊速制备的“非晶带”,有10nm左右和150-200nm的析出物分布在非晶基体上。析出物的生成,促进了矫顽力的提高。     

Interaction of surface of ribbons of amorphous soft-magnetic iron-based alloys with vapor

The interaction with water vapor of the surface of ribbons of amorphous soft-magnetic iron-based alloys with positive saturation magnetostriction and an effect of the interaction on the magnetization distribution and magnetic properties have been investigated. The results of the investigation showed that, during in-air heat treatment, the interaction of the surface of ribbons of amorphous soft-magnetic alloys with water vapor upon the heating of samples and at the initial stage of isothermal holding exerts a substantial effect on the magnetization distribution and the level of magnetic properties formed. Preliminary room-temperature treatment of the ribbon surface in the as-quenched state with water vapor favors an increase in pseudo-uniaxial tensile stresses along the ribbon axis because, during annealing, the enhanced concentration of hydrogen and oxygen atoms introduced into the ribbon surface is formed in this direction. When certain regimes of heat treatment are used, this leads to an increase in the volume of domains with magnetization oriented along the axis of the ribbon in its plane and allows a significant enhancement in the efficiency of the in-air heat treatment.     

Effects of Ribbon Thickness on Structure and Soft Magnetic Properties of a High-Cu-Content FeBCuNb Nanocrystalline Alloy

The effects of ribbon thickness (t) on the structure and magnetic properties of a Fe_82.3B₁₃Cu_1.7Nb₃ alloy in melt-spun and annealed states have been investigated. Increasing the t from 15 to 23 μm changes the structure of the melt-spun ribbons from a single amorphous phase to a composite with dense α-Fe nanograins embedded in the amorphous matrix. The grain size (D_α-Fe) of the α-Fe near the free surface of the ribbon is about 6.7 nm, and it gradually decreases along the cross section toward the wheel-contacted surface. Further increasing the t to 32 μm coarsens the D_α-Fe near the free surface to 15.2 nm and aggravates the D_α-Fe ramp along the cross section. After annealing, the ribbon with t = 15 μm has relatively large α-Fe grains with D_α-Fe > 30 nm, while the thicker ribbons possessing the pre-existing nanograins form a finer nanostructure with D_α-Fe < 16 nm. The structural uniformity of the ribbon with t = 23 μm is better than that of the ribbon with t = 32 μm. The annealed ribbons with t = 23 and 32 μm possess superior soft magnetic properties to the ribbon with t = 15 μm. The ribbon with t = 23 μm exhibits a high saturation magnetic flux density of 1.68 T, low coercivity of 9.6 A/m, and high effective permeability at 1 kHz of 15,000. The ribbon with t = 32 μm has a slightly larger coercivity due to the lower structural uniformity. The formation mechanism of the fine nanostructure for the ribbons with suitable t has been discussed in terms of the competitive growth effect among the pre-existing α-Fe nanograins.     

Structure and magnetic characterization of amorphous and crystalline Nd–Fe–Al alloys

Glass formation has been studied in Nd₆₀Fe₃₀Al₁₀ alloy produced by melt-spinning, water quenching and copper mold chill casting. Partially amorphous alloys were obtained by melt-spinning at low wheel speeds of 5 to 15 m/s and by water quenching of a 1-mm diameter rod, while fully amorphous alloys were obtained by melt-spinning at higher wheel speeds of 20 and 30 m/s and chill casting of a 1-mm diameter rod. A high coercivity was observed in the partially amorphous ribbon melt-spun at 5 m/s and water quenched rod, and in the fully amorphous chill cast rod, while low values of coercivity were obtained in fully amorphous ribbons melt-spun at high speeds of 20 and 30 m/s. Crystallization of water quenched and chill cast samples after heat treatment at high temperature resulted in a substantial reduction of the high coercivity. Results of X-ray diffraction indicate that formation of Nd and a ternary Fe–Nd–Al phase with an unknown crystal structure were present after crystallization. TEM results and a magnetic study of the heat treated samples indicate that as long as there is an amorphous phase produced by low cooling rate, the high coercivity remains. The high coercivity of bulk amorphous samples is discussed. The unknown ternary Fe–Nd–Al phase is antiferromagnetic with a Neel temperature at about 260 K.     

Structural, thermal and magnetic properties of Fe-Si-B-P-Cu melt-spun ribbons: Application of non-isothermal kinetics and the amorphous random anisotropy model

The microstructural variation of Fe-Si-B-P-Cu melt-spun ribbons was analyzed on the basis of non-isothermal kinetics and the amorphous random anisotropy model. The magnitude of latent heat of the crystallization process obtained from DSC curves increases with the increase of quenching wheel speed. The apparent activation energies of the nucleation and growth of α-Fe nanocrystallites increase as the quenching wheel speed increases. Thermal analysis implies that the size of the local short-medium order (cluster) in melt-spun ribbons reduces with the increase of quenching wheel speed. Meanwhile, magnetic measurements display that the coercivity of the stress-released ribbons decreases with the increasing quenching wheel speed. This confirms the thermal analysis results on the basis of the amorphous random anisotropy model. Combing thermal analysis with magnetic measurements, it is believed that the cluster size of the melt-spun ribbons decreases with the increase of the cooling rate during melt-spinning process. Nanocrystalline alloy with desirable microstructure and soft magnetic properties is anticipated to be obtained from an amorphous alloy prepared at an appropriate cooling rate by adjusting the quenching wheel speed.     

带厚对FeSiB非晶铁芯软磁性能的影响

研究了带材厚度对非晶环形铁芯软磁性能的影响,铁芯由标称成分为Fe91.7Si5.3B3.0(质量分数),分别为带厚22μm,25μm和26μm的带材制成。铁芯在氮气保护下经过653~723K保温1h进行热处理。在5~30kHz以及200~1 000mT(Bm)范围内测试铁芯软磁性能。研究表明,带材厚度影响铁芯软磁性能,随着带材厚度的减小,铁芯动态损耗值、矫顽力和剩磁都逐渐减小,带厚22μm带材绕制的铁芯可以获得最优的软磁性能。     

快速凝固新型Au-Ag-Ge合金薄带的制备

采用单辊快速凝固法制备了Au-19.25Ag-12.80Ge合金薄带。利用TEM方法对合金薄带的显微组织进行了观察分析,根据热传输平衡方程对快速凝固过程冷却速率进行估算。结果表明:辊面线速度在18~24 m/s范围内时,快速凝固冷却速率可达8.93×105~1.293×106K/s,随着快速凝固冷却速率的增加,合金薄带厚度有所减小;单辊快速凝固工艺的冷却速率对合金薄带的显微组织有重要影响,由于快速凝固工艺增加了材料的固溶度,减小了成分偏析,细化了晶粒,因此显微组织更加均匀细小,形成了纳米晶,快速冷却工艺在金属熔液内垂直于辊轮方向上产生的冷却速度梯度,造成了晶粒内部应力集中现象的产生。     

Effect of parameters of heat treatment on magnetic properties and magnetization distribution in ribbons of amorphous soft magnetic iron-based alloys

The effect of the isothermal-holding temperature and cooling rate upon in-air heat treatment on the magnetic properties and magnetization distribution in ribbons of amorphous soft magnetic iron-based alloys with positive saturation magnetostriction has been investigated. The results of the investigation showed that the dependence of the maximum magnetic permeability on the isothermal-holding temperature correlates with the corresponding changes in the magnetization distribution in the ribbon and is determined by diffusion processes that occur upon in-air heat treatment at a specific isothermal-holding temperature. An increase in the cooling rate leads to an ambiguous effect on the level of magnetic properties. The increase favors an improvement in magnetic properties when, after in-air heat treatment, either a predominantly amorphous state of the surface or a state with the formed amorphous-crystalline surface layer with a nearly optimal thickness is obtained.     

Al86Fe10Zr4非晶合金的晶化与腐蚀行为研究

利用甩带法制备出Al86Fe10Zr4非晶薄带,用X射线衍射仪和差示扫描量热计对该非晶的非晶特性及晶化过程进行了研究.结果表明,Al86Fe10Zr4非晶薄带的晶化过程为两步晶化,其晶化温度分别约为603和718 K.用Kissinger 法得到了合金两步晶化过程的激活能分别为273和239 kJ/mol.对该非晶薄带...