化学镀钴-镍-磷合金镀层沉积速度的探讨

化学镀钴－镍－磷合金镀层具有良好的磁学性能,正日益受到人们的青睐。由于沉积速度往往对镀层性能产生很大影响,在此重点了影响化学镀钴－镍－磷合金镀层沉积速度的各因素。结果表明,提高镀液中金属离子总浓度及镍盐所占的比例,在ＰＨ为８￣１０范围内加入适量的稳定剂及采用活性强的基材有利于化学镀钴－镍－磷合金镀层沉积速度的提高。     

化学镀钴工艺试验小结

化学镀钴是利用强还原剂——次亚磷酸钠在化学镀钴溶液中的还原作用,使钴离子还原成金属钴,沉积在待镀零件表面。由于还原剂中含磷,所以获得的是钴磷合金沉积层。化学镀钴能避免电镀时因镀件几何形状复杂而造成的电力线分布不均,均镀能力差的缺陷,改善了镀层抗蚀,耐磨等性能,得到孔隙率低,均匀致密的镀层。化学镀钴层系磁性镀层,可应用于记忆存储器件上,由于它的记录性能优于传统的氧化铁涂层,因此化学镀钴引起了人们深入的研究。     

化学镀Co-Ni-P合金薄膜化学成分的考察

考察了影响化学镀Ｃｏ－Ｎｉ－Ｐ合金薄膜化学成分的因素,镀液中ｃｃｏ＾２＋／（ｃｏ＾２＋ｃＮｉ＾２＋）的比值越高和总金属离子浓度越低,薄膜的钴含量越高,镍和磷的含量越低。较高的ｐＨ值和较厚的薄膜会提高薄膜的钴含量,降低镍含量,磷元素倾向于偏聚在晶界上。     

化学镀CoWP薄膜的制备及磁性研究

利用化学镀的方法制备了CoWP磁性薄膜。研究了施镀时间对化学镀CoWP薄膜矫顽力和饱和磁化强度的影响,并利用场发射扫描电子显微镜(FSEM)、X射线衍射(XRD)和振动样品磁强计(VSM)研究了CoWP磁性薄膜的表面形貌、成分、微结构及磁学性能。结果表明,化学镀CoWP薄膜主要为hcp结构Co相,晶粒大小为2~3μm;随着施镀时间的增加,CoWP薄膜的饱和磁化强度也随之增大,最高达到122emu/g;CoWP薄膜的矫顽力都在250Oe以下。通过计算Kelly-Hankel(δM)曲线,证实了CoWP磁性薄膜中存在交换耦合作用,产生了剩磁增强效应。     

SiCw-Co复合材料的制备及吸波性能的研究

为了改善SiC晶须的磁损耗性能,提高吸波性能,扩大其在科技、军事等领域的应用范围。本实验采用化学镀钴的方式制备SiCw-Co复合材料,选定化学镀溶液中硫酸钴的质量、化学镀的时间、化学镀的温度三个因素,设计了一个“三因素三水平”的正交实验,运用极差分析法讨论硫酸钴的质量、化学镀的时间和温度对SiCw-Co复合材料吸波性能的影响,最终得到制备SiCw-Co复合材料的最佳工艺。结果表明:在SiC晶须表面镀钴的最佳条件:化学镀溶液中硫酸钴的质量为8.0 g,化学镀时间为5 min,化学镀的温度为80℃。此时SiCw-Co复合材料的吸波性能最好,反射损失率最小为-20.12 dB,低于-10 d B的波段宽度约为3 GHz,同时具有一定的介电损耗和磁损耗能力。     

超声波诱导下化学镀制备钴-镍合金薄膜

在超声波诱导下化学镀制备钴-镍合金薄膜,并研究了超声波功率对沉积速率及薄膜性能的影响。结果表明:选择适当功率的超声波,有利于提高沉积速率,降低薄膜的表面粗糙度,细化薄膜表面的微粒,从而大大提高薄膜的耐蚀性。当超声波功率大于100 W时,剧烈的空化效应降低了还原剂的稳定性,使得薄膜表面团聚开裂,耐蚀性降低。     

硼氢化钠对滑轮用铸钢板化学镀Ni-B合金薄膜性能的影响

在滑轮用铸钢板上化学镀Ni-B合金薄膜,并研究了硼氢化钠的质量浓度对化学镀Ni-B合金薄膜性能的影响。结果表明:适当增加硼氢化钠的质量浓度,有利于增大化学镀Ni-B合金薄膜的厚度及硼的质量分数,从而提高化学镀Ni-B合金薄膜的硬度。当硼氢化钠的质量浓度大于1.2 g/L时,硼氢化钠的水解速率加快及剧烈的析氢反应,导致化学镀Ni-B合金薄膜的厚度及硬度有所降低。当硼氢化钠的质量浓度为1.2 g/L时,化学镀Ni-B合金薄膜表面"胞状"颗粒均匀、致密,摩擦因数和磨损率最低,具有最佳的耐磨性。     

SmCo薄膜的共溅射制备及磁学性能研究

采用磁控共溅射方法制备了非晶态的SmCo磁性薄膜,用振动样品磁强计(VSM)分析了薄膜的磁学性能,并通过原位后退火处理研究了其磁学性能。结果表明,在600℃下退火30分钟,SmCo薄膜样品的矫顽力升高,并且磁化取向有从面内转向垂直方向的趋势。     

化学镀空心玻璃微珠基吸波材料的研究进展

化学镀作为一种空心玻璃微珠的改性手段,其工艺设备简单、镀层厚度均匀且镀层包覆性能好,作为吸波材料被广泛使用。简述了化学镀的发展和原理,综述了利用化学镀银、化学镀镍、化学镀钴和化学镀铜表面改性后空心玻璃微珠基吸波材料的研究现状。指出化学镀铜法表面改性后的空心玻璃微珠因其成本低和吸波性能良好将成为发展趋势。     

化学镀非晶态镍磷合金镀层抗氧化性能研究

化学镀镍磷合金镀层由于其非晶态结构而具有优良的性能。为进一步拓宽其应用领域,通过比较试验,研究了化学镀镍磷合金层及不锈钢在５００℃及高温常温冷热交替环境中的耐蚀性和抗氧化性。试验发现,在１００ｈ内,化学镀镍磷合金层在５００℃下的增重与不锈钢基本相同,经氧化后,镀层磷含量显著降低,在盐溶液循环氧化试验中,化学镀镍磷合金层在上述条件下具有良好的耐蚀性和抗氧化性。     

组织结构对Co-Ni-P薄膜形貌和磁性的影响

化学镀 Co- Ni- P薄膜镀态下为非晶态结构 ,表面较为平整 ;经 30 0℃× 1 h热处理 ,发生了晶化转变 ,表面由“圆锥峰“所构成 ;随加热温度的提高 ,镀层析出了 Co2 P相 ,并发生了由密排六方结构的α- Co向面心立方结构的β- Co的同素异构转变。非晶态 Co- Ni- P薄膜的矫顽力较低 ,矩形比较高 ;薄膜向晶态转变时 ,矫顽力和矩形比皆呈上升趋势 ;50 0℃× 1 h热处理 ,薄膜由α- Co和 Co2 P相构成时 ,且在晶界上偏聚较多磷的影响下 ,矫顽力和矩形比的值达到最高 ;温度继续升高 ,晶粒长大 ,第二相粗化时 ,薄膜的矫顽力和矩形比都减小。化学镀 Co- Ni- P薄膜具有优秀的高密度垂直记录特性。     

化学镀非晶态Co-Ni-P薄膜磁性的研究

化学镀Ｃｏ－Ｎｉ－Ｐ薄膜镀态下为非晶态结构,Ｃｏ－Ｎｉ－Ｐ薄膜的矫顽力较低,矩形比较高,其易磁化方向与膜面垂直。薄膜越厚,矫顽力越高,矩形比越低;镀液的ｐＨ值越高,矫顽力越高;当以化学镀Ｎｉ－Ｐ合金作为中间镀层时,可获得较高的矫顽力和矩形比。     

Magnetic properties of nanocrystalline iron group thin film alloys electrodeposited from sulfate and chloride baths

Systematic studies of iron group binary (NiCo and CoFe) and ternary (CoNiFe) thin film alloys relating their magnetic properties with film composition, grain size and the corresponding crystal structure were investigated. Anions influence current efficiencies, magnetic properties, surface morphology and phases of electrodeposited films. Higher current efficiencies in chloride baths compared to sulfate baths were observed for CoFe, NiCo and CoNiFe alloys. The higher deposition current efficiencies in chloride baths were attributed to a catalytic effect. Anion types in CoFe and CoNiFe thin film alloys influenced the microstructures and the resulting magnetic properties (coercivity and squareness). The microstructures of NiCo alloys depend on the deposit Co contents rather than anion types. The surface morphologies of CoFe, NiCo and CoNiFe thin films were independent of anion types. CoFe deposits exhibited relatively smooth surface morphology and turned into fine crystallites with increasing solution Fe⁺² concentration. NiCo deposits showed very smooth surface morphology. CoNiFe deposits had the surface morphology of polyhedral crystallites. The deposit Fe content in CoFe electrodeposits linearly increased with increasing solution Fe⁺² concentration for both chloride and sulfate baths. Similar linear behavior of deposit Co contents was observed in NiCo electrodeposits.     

磁控溅射法制备铁氧体薄膜的磁性能研究

采用溶胶-凝胶法制备纳米晶镍锌钴铁氧体/二氧化硅复合粉体,并将该粉体制成靶材.采用磁控溅射法在单晶硅基底和玻璃基底上沉积镍锌钴铁氧体复合薄膜,并对其进行磁性能研究.研究结果表明:镍锌钴铁氧体/二氧化硅复合薄膜具有较好的软磁性能;在相同的溅射条件下,两种基片上的薄膜的矫顽力都较小,但硅基片上薄膜的饱和磁化强度较玻璃基片上的大,软磁性能更好;经后退火处理,薄膜的饱和磁化强度得到明显地提高,软磁性能得到改善.     

Electrodeposition of low-stress high magnetic moment Fe-rich FeCoNi thin films

Low-stress high magnetic moment Fe-rich FeCoNi thin films were electrodeposited from acidic chloride baths to investigate the effects of the deposition temperature, solution pH and l-ascorbic acid on film morphology, crystal structure, magnetic properties and film stress. As the deposition temperatures were increased from 23 to 70 °C, the film stress in the FeCoNi films decreased from 260 to 28 MPa at pH 1.5 in the absence of l-ascorbic acid. The film stresses further decreased to approximately 0 MPa when solution pH was increased to 2.15. However, the plating baths became unstable at pH higher than 2.15 because of precipitate formation. On increasing the deposition temperature, the deposit Fe content in the FeCoNi thin films decreased from 83 to 72 atomic percent (at.%) and the Co content increased from 17 to 27 at.%. In the case of the deposit Ni content, it slightly increased with increasing deposition temperature. From the XRD analysis, the change of the preferred planes from the bcc (1 1 0) to bcc (2 0 0) with increasing deposition temperatures was observed. It is believed that the changes in the grain size and the incorporation of impurities during electrodeposition influenced the stress of the FeCoNi films. The presence of l-ascorbic acid enhanced the stability of the baths at high pH meanwhile reducing current efficiencies. With increasing deposit Ni content, magnetic saturation (B_S) and parallel squareness slightly decreased and increased, respectively.     

Development of an electroless CoNiZnP solution for high coercivity films

This paper describes the development of an electrolessly deposited CoNiZnP film for use in magnetic storage devices. A low temperature type solution, which can be operated at 310 K, has been developed. High coercivity films, which have a coercivity of 135 kA m^–1 (1700 Oe) at a film thickness of 80 nm, are deposited from the solution     

固体平壁上受热降膜分布模型

在降膜受热流动过程中,由于液膜边缘与膜中央之间存在速度差异,造成液膜横向温度分布不均,由此在液膜横向产生了表面张力梯度, 即引起了自液膜边缘向液膜中央的Marangoni流动,从而使得液膜收缩变形. Marangoni流动引起的收缩效应与液体润湿性及流动压力的扩展效应相互作用, 在液膜边缘形成了凸起区. 根据液膜边缘凸起区内的受力平衡和物料平衡关系,同时考虑温度引起的表面张力梯度对液膜流动的影响,建立了受热降膜收缩模型. 此模型显示, 较低的壁温、较小的固液接触角以及较大的液体流量有利于液膜在加热固体壁面上的扩展. 通过与实验数据的对比显示,该模型较准确地预测了受热液膜下落初始过程中的液膜分布, 能够为传质传热过程及其设备的优化设计提供理论依据.     

热处理对TiO_2薄膜微观力学性能的影响

采用喷涂法在5mm普通浮法玻璃上制备了纳米级锐钛矿型TiO2薄膜,并进行了不同温度的热处理。采用原子力显微镜、X射线衍射仪和纳米压痕仪分析了薄膜的形貌、结构和微观力学性能。讨论了热处理温度对纳米TiO2薄膜微观力学性能的影响。结果表明:随着热处理温度由20℃升高到500℃,薄膜中TiO2均变为锐钛矿型,平均晶粒尺寸略有增加,薄膜表面平整;随热处理温度从350℃升至500℃,平均粗糙度由12.516nm降低至11.433nm;热处理后纳米压痕硬度和弹性模量均有增加,分别由412.6MPa,14.9GPa增加到908.3MPa,28.4GPa;塑性指数逐渐增大,由0.028增大到0.032;摩擦因数由0.166降低到0.120。     

Magneto-optic and magneto-electric effects in poly(vinylidene fluoride) - Zn0.2Co0.8Fe2O4 nanocomposite organic flexible film

The inorganic-organic multiferroic magnetoelectric materials possess extensive research interest for an application point of view considering the flexible magnetoelectric devices. The ferroelectric polymer based poly(vinylidene fluoride) - Zn_0.2Co_0.8Fe₂O₄ magnetoelectric flexible having self-standing nanocomposite film has been prepared through the low temperature chemical process and followed by the solution casting technique. The structural characterizations have been carried out by X-ray diffraction technique. The surface morphology of this film is analysed using atomic force microscopic topography. The electrical properties of the flexible film have been observed with an induced effect of confirmable visible light, where the magnetic field produces a significant influence. The combined effect of the visible light and the magnetic flux is controlling the electrical properties of the film. This film is showing the resistive switching effect with time and the radiation of light energy at room temperature. The magnetoelectric coupling coefficient of the flexible film has been measured as a function of an applied magnetic field at different experimental configurations at room temperature. The attempted research work provides an information about the visible light and magnetic field induced effects of the magnetoelectric material. However, it may be extended for an application purpose to develop the multiferroic magnetoelectric based devices.     

Magnetic Ceramics: V, Magnetic Properties of Square Loop Ferrites Within the System MgO-MnO-Fe2O3

Thirteen compositions within the center of the system MgO-MnO-Fe₂O₃ were investigated because of their rectangular hysteresis-loop characteristic. Initial permeabilities were measured, and B_m, B_T, H_c , and R_8m were obtained from quasi-static hysteresis loops. High MgO content was found to be detrimental to the magnetic properties and to impair the loop rectangularity. The highest hysteresis-loop squareness ratio, R, _8m , was found in a composition with high Fe₂O3 content, and the lowest coercive force, H_c , was found in a composition with high MnO content.