Fe基非晶合金涂层在晶化过程中的硬度与组织变化

对等离子喷涂含Cr，Ni，W，Mo，C，Si等合金元素的Fe-B基非晶合金涂层进行了100～730℃不同温度4h热处理试验。差热分析结果表明，涂层的急剧结晶温度在590℃附近。热处理试验结果表明，在450℃以下热处理时，涂层仍基本保持非晶态，硬度变化不大。在450～610℃之间热处理时，随温度升高，涂层逐渐晶化，析出以Fe23(C，B)6和Fe23B6相为主的硬质相和富Fe相，在590℃左右获得晶粒尺寸约为20nm纳米晶组织，涂层硬度随温度升高急剧增大，在610℃左右硬度达到最大值，约1270HV。在630～730℃之间热处理时，富Fe相逐渐成为主要相，并有Fe23(C，B)6，Fe23B6，Fe2B和FeB等多种硬质硼化物相形成，晶粒尺寸随温度升高长大并形成树枝晶，涂层硬度逐渐降低。     

Cu对Fe基非晶合金内禀磁性及晶化行为的影响

利用ＤＳＣ，ＸＲＤ，ＴＥＭ，Ｍｏｓｓｂａｕｅｒ谱及磁性测量技术研究了Ｃｕ取代Ｆｅ对ＦｅＳｉＢ非晶合金的内禀磁性及晶化行为的影响。结果表明：Ｃｕ元素取代Ｆｅ使ＦｅＳｉＢ非晶合金的λｓ，σｓ，Ｈｆ，μＦｅ下降，但居里温度Ｔｃ升度。而且，Ｃｕ的加入能够显著地降低ＦｅＳｉＢ非晶合金的晶化温度及晶化激活能，改善αＦｅ（Ｓｉ）相的形貌。ＦｅＣｕＳｉＢ非晶合金的晶化行为表明：在非晶合金内部存在αＦｅ（Ｓｉ）相成     

Zr对Pr-Fe-B非晶合金晶化形成纳米晶合金的作用

从非晶合金化激活能的角度，分析了Pr-Fe-B非晶合金在退火过程中晶粒粗大的原因，揭示了Zr元素在其晶化过程中的作用，结果表明，Zr能改变Pr-Fe-B非晶合金中α－Fe相的晶化行为，有助于形成尺寸细小的α-Fe相。     

Fe基非晶合金涂层的多晶型晶化过程研究

等离子喷涂Fe基非晶合金涂层的晶化温度在590℃左右.在高于晶化温度热处理时,涂层首先以多晶型晶化方式直接结晶形成亚稳的Fe23(c,B)6和Fe23B6化合物相.随热处理时间延长,Fe23(C,B)6和Fe23B6相发生分解,逐渐转变为更稳定的Fe3B相和Fe固溶体相.热处理温度越高,Fe23(C,B)6相和Fe23B6相的分解转变速度越快.随热处理温度升高或时间的延长,晶化涂层的硬度呈线性降低.经590℃,4h热处理后,涂层结晶形成纳米晶组织;经660℃,4h热处理后,涂层结晶形成树枝状晶组织,随热处理温度升高,涂层中扁平状粒子间结合增强并趋于熔合,晶粒发生长大.     

Cu对Fe基非晶合金内禀磁性及晶化行为的影响

利用 DSC,XRD,TEM,M(?)ssbauer 谱及磁性测量技术研究了 Cu 取代 Fe 对 FeSiB 非晶合金的内禀磁性及晶化行为的影响。结果表明:Cu 元素取代 Fe 使 FeSiB 非晶合金的λ_s,σ_s,(?)_f,(?)_(Fe)下降,但居里温度 T_c 升高。而且,Cu 的加入能够显著地降低 FeSiB 非晶合金的晶化温度及晶化激活能,改善x-Fe(Si)相的形貌。FeCuSiB 非晶合金的晶化行为表明:在非晶合金内部存在α-Fe(Si)相成分富集区。     

非晶合金COFeNbSiB的纳米晶化及磁性

研究了Co68Fe7Nb5Si12B8和Ｃo64Fe11Nb5Si12B8两种非晶合金在４００－５８０℃温度间等温退火１h后的纳米晶化行为和磁性,结果表明,在４５０－５６０℃退火１h后,在两种晶合金的基体上均析出上了单一相bcc结构的α－Ｆe(Co)固溶体,当退火温度（Ｔa）低于４７０℃时,合金具有很好的晶化相Ｃo-B,Fe-B及其它化合物析出,磁性变得比较软,这可能是由于具有bcc结构的α－Ｆe(Co)相最大有大的磁致伸缩。     

Sm-Fe-Si-C非晶合金的晶化动力学

用差热分析（ＤＴＡ）,结合Ｘ射线衍射（ＸＲＤ）研究了Ｓｍ－Ｆｅ－Ｓｉ－Ｃ非晶态合金的晶化动力学。结果表明：温度低于９００℃时,该合金晶化相为α－Ｆｅ（Ｓｉ）固溶体和Ｓｍ２（Ｆｅ,Ｓｉ）１７Ｃｘ。α－Ｆｅ（Ｓｉ）相的晶化表观激活能为４３１．５１ｋＪ／ｍｏｌ,Ｓｍ２（Ｆｅ,Ｓｉ）１７Ｃｘ相的晶化表观激活能为５１４．４３ｋＪ／ｍｏｌ。上在晶化初期活能变化不大,当α－Ｆｅ（Ｓｉ）相的体积分数大于７０％,Ｓ     

Co对Nd-Fe-Al大块非晶合金的晶化行为和磁性能的影响

采用示差扫描量热法(DSC)，X射线衍射(XRD)和振动样品磁强计(VSM)研究了Co对Nd—Fe-Al大块非晶合金的非晶形成能力，晶化行为和磁性能的影响。结果表明：加入Co元素后可以显著提高Nd—Fe-Al大块非晶合金的非晶形成能力以及提高合金的居里温度。Nd60Fe30-xAl10Cox(z=0、5、10)大块非晶合金在室温有较高的内禀矫顽力，具有硬磁性。内禀矫顽力随着Co含量的增加变化不大．但是饱和磁化强度和剩磁则随着Co含量的增加有所下降。Nd60Fe3-xAl10Cox(x=0、5、10)大块非晶合金具有的硬磁性能来自于非晶相。合金少量晶化后，磁性能变化不大。完全晶化后合金的硬磁性迅速消失。     

预退火温度对Cu基块状非晶玻璃转变及晶化的影响

采用差示扫描量热（Dsc）分析方法测定了Cu50Zr42Al8块状非晶合金在不同温度（350～450℃）预退火4h后的玻璃转变温度Tg、起始晶化温度Tx、晶化峰值温度Tp和玻璃转变过程中的比热容变化。结果表明：预退火处理试样的玻璃转变温度Tg、玻璃转变比热变化ΔCp，g随退火温度的升高呈现逐渐增加的趋势，而其起始晶化温度Tx和晶化峰值温度Tp随退火温度的变化不明显。并利用结构弛豫理论分析了预退火温度对玻璃转变和晶化的     

Cr/Mo比对FeCoMoCrZr非晶合金晶化过程及磁性能的影响

采用单辊急冷法制备了一系列不同Cr/Mo比的FeCoMoCrZr非晶薄带,并对该系非晶合金进行等温热处理。用XRD和VSM研究Cr/Mo比的变化对(Fe0.58Co0.42)73Mo17-xCrxZr10系非晶合金晶化过程和磁性能的影响。结果表明,x在9~17之间变化时,所制备的合金薄带为非晶结构;(Fe0.58Co0.42)73Mo5Cr12Zr10非晶合金的晶化过程为:Am→α-Fe(Co)+CrFe4+Fe23Zr6+Cr2Mo,(Fe0.58Co0.42)73Cr17Zr10非晶合金的晶化过程为:Am→α-Fe(Co)+Am′→α-Fe(Co)+CrFe4+Fe3Ni2+未知相;Cr/Mo比例的增加降低了合金的热稳定性,促进了退火后α-Fe(Co)相的析出。两种合金的饱和磁化强度Ms随退火温度的变化趋势相同但幅度不同,在低于晶化峰值温度Tp退火,(Fe0.58Co0.42)73Mo5Cr12Zr10合金的Ms随退火温度的升高缓慢上升;而(Fe0.58Co0.42)73Cr17Zr10合金的Ms随退火温度的升高快速大幅上升。     

Finemet-Co非晶合金的结晶动力学研究

利用标准的单棍甩带技术在大气环境下制备了Fe73.5-xCOxSi13.5B9Cu1Nb3 (x=10、30,50)非晶条带.在550和600℃下分别对非晶条带进行真空等温退火1h,从而在非晶基体中形成纳米晶相.X射线衍射(XRD)分析结果表明,550和600℃真空等温退火1h后,Fe73.5-xCOxSi13.5B9...     

Influence of microstructure and hydrogen concentration on amorphous silicon crystallization

Hydrogenated amorphous silicon samples were deposited on glass substrates at different temperatures by high frequency plasma-enhanced chemical vapor deposition. In this way, samples with different hydrogen concentrations and structures were obtained. The transition from an amorphous to a crystalline material, induced by a four-step thermal annealing sequence, has been followed. Effusion of hydrogen from the films plays an important role in the nucleation and growth mechanisms of crystalline silicon grains. Measurements of hydrogen concentrations, Raman scattering, X-ray diffraction and UV reflectance showed that an enhanced crystallization was obtained on samples deposited at lower substrate temperatures. A correlation between these measurements allows to analyze the evolution of structural properties of the samples. The presence of voids in the material, related to disorder in the amorphous matrix, results in a better quality of the resulting nanocrystalline silicon thin films.     

Zr对非晶Co-Si薄膜晶化和相变的影响

利用X射线衍射分析技术结合差示扫描量热仪,研究了Zr在Co-Si合金非晶薄膜晶化和相变过程中的作用.结果表明:溅射态非晶Co-Si薄膜和Co-Si-Zr薄膜在加热到950℃的过程中,均主要析出Co-Si和Co-Si2两种晶化相;Zr的加入增大了晶化激活能,抑制了晶化相的形核和长大,使薄膜能够在更高的温度范围保持稳定,但在高温800℃以上加热时,却使晶化相Co-Si向Co-Si2的转变加快.     

Influence of chemical composition and excess free volume on surface crystallization of amorphous alloys

Small-angle x-ray scattering and electron Auger spectroscopy were used to study the distribution of the excess free volume and the chemical composition of the surface layers of amorphous alloy ribbons. The relationship between these structure parameters and the surface crystallization characteristics of amorphous alloys is analyzed. Pis’ma Zh. Tekh. Fiz. 24, 58–64 (December 12, 1998)     

Preparation and crystallization of chromium-based amorphous alloys

The glass formability of the Cr₇₂ (B, Si, C)₂₅Al₃ system has been investigated. Samples were prepared by rapid quenching from the melt by the melt spinning technique. Of the compositions investigated, only Cr₇₂B₁₀C₁₀Si₅Al₃ and Cr₇₁ C₁₇Si₈Al₃ formed fully amorphous alloys. These showed crystallization temperatures of 997 and 990 K, respectively, among the highest reported for transition metal-metalloid amorphous alloys. The crystallization products have been found to be Cr₇C₃ and Cr₃(Si, B) for Cr₇₂B₁₀C₁₀Si₅Al₃ and Cr₇C₃ and Cr₃Si for Cr₇₂C₁₇Si₈Al₃. The effects of substituting iron in place of chromium in Cr₇₂C₁₇Si₈AI₃ have been investigated. For up to 20 at% Fe the crystallization products are (Cr, Fe)₇C₃ and Cr₃Si. An alloy with 30 at% Fe crystallizes into (Cr, Fe)₇C₃ and hexagonal Cr-Si-C.     

Characteristic features of silumin alloys crystallization

The results differential thermal analysis (DTA) of crystallization of multicomponent silumin alloys with 8÷22 wt %Si and Mg, Cu, Ni and Fe minor admixtures are presented in the paper. It has been proved that to any one of the solid phases crystallizing from liquid (, β, Mg₂Si, Al₆Cu₃Ni, Al₂Cu, Al_gFe₂Si) a particular thermal effect can be deduced and identified. A new hypothesis concerning hypereutectic silumin alloys crystallization has been proposed in the work.     

Formation and crystallization of Al-Fe-Si amorphous alloys

Rapid solidification experiments of Al-based Al-Fe-Si ternary alloys have been performed both by the gun and single roller methods. Glass forming tendency is found to be largest near theβ-phase (Al₉Fe₂Si₂) composition, where the amorphous state is obtained both by the gun and single roller methods. Crystallization behaviour of amorphous AlFe_13.0Si_17.4 alloy, nearβ-phase composition, followed the course of (i) the appearance of fineα-Al particles and (ii) the transformation of the matrix intoβ-phase. The ratio of crystallization temperature and the melting point,T _x/T _m, for AlFe_13.0Si₂17.4 amorphous alloy is smaller than 0.5 indicating the difficulty of glass formation of these alloys.     

In-situ observation of phase transformation in amorphous silicon during Joule-heating induced crystallization process

During the Joule-heating induced crystallization (JIC) process of amorphous silicon for display applications, its phase transformation from amorphous to polycrystalline phases occurs through two different kinetic paths of either solid-to-solid or solid-to-liquid-to-solid phases. Depending on input conditions such as power density and pulsing time, each path results in nano-crystalline silicon phases or large grain structures produced by lateral growth, respectively. In this study, the phase-transformation phenomena during the JIC process were detected electrically and optically by the in-situ measurements of input voltage/current and normal reflectance at wavelength of 532 nm. The temperature field estimated from a simple conduction model confirms the phase-transformation behavior observed experimentally. In addition we could obtain the poly-Si structure produced by solid phase crystallization having the process time of 250 μs and reaching the highest temperature around 1350 K.