扁平化对FeSiAl合金结构及电磁特性的影响

通过球磨对气雾化FeSiAl合金粉末进行扁平化,并制备成软磁合金复合材料(SCM)。研究球磨时间对合金粉末微观形貌、显微结构以及1MHz~1GHz频率范围内SCM的复磁导率的影响。结果表明:随着球磨时间的增加,合金粉末的扁平率由1.18增大到7.01,粒径由50.36μm减小到33.31μm,平均晶粒尺寸由79.7nm减小到49.7nm,内应变由0.4252%增大到0.5974%;对合金粉末进行球磨可以明显提高SCM的μ′和μ″;随着球磨时间增加,SCM在同频率下的μ′和μ″均逐渐增大。     

FeSiAlCr片状合金微粉超精细结构对材料饱和磁化强度的影响

为了研究FeSiAlCr片状合金微粉的超精细结构和材料饱和磁化强度的影响关系,本文对合金微粉进行了不同温度的退火处理,并对合金微粉进行XRD、穆斯堡尔谱测试。研究发现通过球磨法获得的片状合金微粉的晶体结构为A2结构(即α-Fe结构),经过高于500℃的氮气保护退火后转变为A2结构和D03超晶格结构。穆斯堡尔谱测试结果显示,使用湿法球磨方法得到的原始合金微粉具有连续分布的超精细磁场,经过高于500℃退火的合金微粉具有分立的超精细磁场,可以使用四种原子占位来进行拟合,显示出更高的有序度。同时,合金微粉的饱和磁化强度和平均超精细磁场有接近线性的关系,均随着退火温度的升高有明显提升。研究中还发现,在退火温度为600℃时,存在超精细磁场和饱和磁化强度的拐点,分析是由于在该温度点退火过程中产生了非磁性的B2相。     

退火工艺对La-Nb共掺杂Bi_4Ti_3O_(12)薄膜结构的影响

采用sol-gel法制备了Si基Bi3.25La0.75Ti2.94Nb0.06O12.03(BLTN)铁电薄膜,研究了退火温度、升温速率和退火时间对BLTN薄膜微观结构的影响。结果表明:制备的BLTN薄膜具有单一的钙钛矿结构,且为随机取向,表面平整致密;退火温度由550℃升高到750℃时,薄膜的衍射峰强度增强,晶粒尺寸由65 nm增大到110 nm;退火升温速率由10℃/min提高为20℃/min时,薄膜的晶化程度降低;退火时间对薄膜的晶相结构影响不大,但时间超过30 min会造成薄膜表面孔洞增多、致密性下降。     

热处理温度对ZrO2薄膜表面形貌和结构的影响

采用溶胶-凝胶法,在302不锈钢表面制备了经不同温度热处理的ZrO2薄膜。通过原子力显微镜(AFM)、X射线衍射仪(XRD)和傅里叶变换红外光谱仪(FTIR),研究了热处理温度对ZrO2薄膜表面形貌和相结构的影响。研究结果表明:室温下ZrO2结构呈非晶态,随着温度升高,晶体结构逐渐由四方相(t-ZrO2)向单斜相(m-ZrO2)转变;当热处理温度从400℃升高到600℃时,薄膜表面ZrO2晶粒尺寸由40 nm逐渐增大到70.1 nm,表面粗糙度也由3.34 nm缓慢增大到5.3 nm;而当热处理温度为700℃时,ZrO2晶粒明显增大(109 nm),表面粗糙度迅速增大到33 nm;红外吸收谱显示,随着热处理温度的升高,非晶态ZrO2(648与460.9 cm-1)逐渐向480.2和574.7 cm-1处的t-ZrO2结构以及424.3和732.8 cm-1处的m-ZrO2结构转变,与XRD结果一致。     

退火温度对WO_3薄膜结构及气敏性能的影响

采用直流磁控溅射法制备了WO3薄膜,并在350~550℃时对薄膜进行退火处理,研究了退火温度对薄膜结构及气敏性能的影响。结果表明:退火前及350℃退火后的薄膜为非晶态,450℃和550℃退火后的薄膜为WO3–x型晶态;随退火温度的提高,薄膜厚度增加,晶粒度增大。550℃退火后薄膜的厚度,较450℃退火后薄膜厚30nm,晶粒度相差8nm;450℃和550℃退火后的薄膜,在150℃时对体积分数为0.05%的NO2的灵敏度接近于22。     

磁场退火对FePt/Ag薄膜磁性能的影响

采用磁控溅射法室温沉积获得FePt/Ag薄膜,然后在500℃下,于真空磁退火炉中对薄膜进行退火处理。利用XRD和振动样品磁强计(VSM),研究了磁场退火对薄膜结构和磁性能的影响。结果表明,500℃零磁场退火获得了矫顽力为0.763 4 MA.m–1、平均晶粒尺寸21 nm的L10-FePt薄膜。磁场提供了FePt成核生长的驱动力,0.8 MA.m–1磁场退火后FePt的平均晶粒尺寸为26 nm,矫顽力增大至0.804 3 MA.m–1。非磁性Ag的掺杂可有效抑制磁性FePt晶粒的团聚生长。     

退火温度对Fe_(40)Co_(40)Zr_7Nb_2AlB_9Cu合金的结构、热行为及磁性能的影响

采用单辊快淬法制备了Fe40Co40Zr7Nb2AlB9Cu非晶合金薄带,在不同温度下对其进行等温退火处理。研究了退火温度对合金的结构、热行为和磁性能的影响。结果表明:Fe40Co40Zr7Nb2AlB9Cu非晶合金的DTA曲线存在2个晶化放热峰,晶化激活能分别为267.3 kJ/mol和188.3 kJ/mol。其晶化过程为:非晶→非晶+α-FeCo→α-FeCo+Co2Zr+ZrCo3B2+Fe(Co)3Zr。α-FeCo相的晶化体积分数和晶粒尺寸随退火温度的升高而逐渐增大。低于873 K退火时,矫顽力变化不明显;873 K退火时,矫顽力达到最小值0.27 kA/m;高于873 K退火时,矫顽力逐渐增大。     

Fe-Cr-Si-B非晶磁粉芯的制备与磁性能研究

以水雾法制备的Fe-Cr-Si-B非晶合金粉末为原料制备了非晶磁粉芯,研究了退火温度和成型压力对磁粉芯性能的影响。结果表明:Fe-Cr-Si-B合金粉末具有较高的非晶化程度和良好的热稳定性;当退火温度低于非晶合金的起始晶化温度时,非晶磁粉芯的起始磁导率μi在440℃附近达到峰值44.7,对应的损耗则相对最低(260×10–3W/cm3,50 kHz);当成型压力由30 MPa增大到50 MPa时,磁粉芯的μi由38.6增大到46.4,其损耗则逐渐降低。     

衬底和退火温度对多晶硅薄膜结构及光学性质影响

通过射频等离子体增强化学气相沉积(RF-PECVD)技术与退火处理制备多晶硅薄膜,研究了衬底和退火温度对所制薄膜的结构及光学性质的影响。本次试验最大的晶粒尺寸是在衬底温度为250℃获得,考虑薄膜表面的质量,最佳的退火温度为635℃,衬底温度为225℃,在玻璃衬底形成的晶粒大于50 nm,光学带隙为1.5 e V。结果表明:衬底温度影响着薄膜中氢含量以及相关的缺陷。随着退火温度的升高,晶化率的提高,光学带隙先减小后增大。     

热处理对点式锻压激光成形GH4169合金组织与力学性能的影响

研究简化热处理制度对点式锻压激光沉积(PF-LF)GH4169合金显微组织和力学性能的影响。将时效时间由原来的18 h减少为3 h,不仅大大节省了试验时间,而且在提升材料性能方面也起到了重要作用。结果表明,在1 010℃固溶时效后,合金中的Laves相出现大部分熔解,合金发生再结晶现象,再结晶晶粒细小且分布均匀,平均晶粒尺寸为6.8μm左右,实现了超细晶组织,合金的强度和塑性也远超锻件标准。1 050℃固溶时效时,再结晶完成,晶粒尺寸略有长大,约为15μm, Laves相基本完全固溶消失,与1 010℃热处理相比,合金的强度有所下降而塑性有所改善,均超过锻件标准。在1 010℃和1 050℃进行双固溶时效时发现,合金中出现了大量的退火孪晶组织,退火孪晶的产生对合金的强度和塑性均产生了影响,虽然合金的性能均超过锻件标准,但略低于单固溶时效状态下的合金性能。     

扁平化及退火温度对FeSiAl合金吸波性能的影响

采用湿磨工艺对水雾化FeSiAl粉末进行了扁平化,然后在不同温度下对其进行了退火处理。借助XRD,SEM和VSM,研究了扁平化工艺和退火温度对FeSiAl粉末物相组成、形貌和静磁性能的影响。另外,借助矢量网络分析仪,考察了以所制合金粉末为吸收剂制成的吸波材料在0.5~4.0 GHz频率范围内的电磁参数与吸波性能。结果表明:经扁平化和退火处理后,FeSiAl吸波材料的复磁导率得到了显著提高。与由未经处理的FeSiAl粉末制成的吸波材料相比,由经扁平化并经700℃退火的FeSiAl粉末制成的吸波材料在0.5~4.0 GHz的低频段具有更加优异的吸波性能。     

特高频高磁损耗材料的制备及其磁特性研究

采用磁粉芯工艺制备了抑制电磁干扰(EMI)用高磁损耗软磁合金复合材料(SCM)。通过SEM微观形貌观察与复磁导率(μr'、μr')测试,对不同制备阶段的样品进行了分析,研究了球磨与退火过程对磁导率的影响,并与铁氧体材料磁导率特性进行了对比。结果表明:μr'呈磁共振双峰宽频分布,1.2GHz时,μr'为7.3,μr'max为14.5。特高频带内,SCM磁损耗性能超过铁氧体材料。     

磁控溅射法制备Ag/FePt/C/FePt薄膜的结构和磁性能

采用磁控溅射法,在自然氧化的Si(001)基片上沉积了Ag/FePt/C/FePt纳米薄膜,并分别在400,450,500,600℃下对薄膜样品进行了1h的退火热处理。利用X射线衍射仪和振动样品磁强计,对薄膜样品的结构和磁性进行了分析。结果表明,当热处理温度为450℃时,Ag/FePt/C/FePt薄膜中已形成了具有有序面心四方结构的L10-FePt。随着热处理温度的升高,薄膜样品的有序化程度提高,矫顽力Hc增强,晶粒尺寸变大。当热处理温度为600℃时,薄膜样品的平行膜面Hc为905.8kA·m-1,晶粒尺寸为23nm。     

退火工艺对钛酸锶钡薄膜结构的影响

采用射频磁控溅射在Pt/Ti/SiO2/Si(100)衬底上制备Ba0.6Sr0.4TiO3(BST)铁电薄膜,在500~750℃之间对薄膜快速退火。XRD分析表明:500℃时BST薄膜开始晶化为ABO3型钙钛矿结构,温度越高结晶越完整,晶粒越大。理论计算表明,薄膜在低温退火后无择优取向,高温退火后在(111)、(210)晶面有择优取向。退火气氛、保温时间、循环次数等因素对薄膜晶粒大小无明显影响,但对表面粗糙度和结晶程度影响较大。     

Microstructure in copper interconnects - Influence of plating additive concentration

Downscaling of copper interconnects is demanding more knowledge about the microstructure and grain growth mechanisms in sub 100 nm dimensions. Large grains are needed to reduce the resistivity and to increase the reliability of narrow lines. Plating additives are used for a void free filling of the interconnecting vias and lines. Fractions of these additives are incorporated into the copper as impurities during electrochemical deposition. In the present paper the role of additive concentration on grain growth is investigated. Interconnect lines from 72 nm to 1.9 μm line width were completely filled with copper using different additive concentrations in the electrolyte. The impurity level was measured by time of flight secondary ion mass spectrometry. The samples were stored at room-temperature to achieve self-annealing or tempered at low and high temperatures. Self-annealing slows down with increasing additive concentration whereas bamboo-like grains are present after annealing all samples at high temperatures. Grain growth was studied as well as the average grain size, resistivity, and {1 1 1} texture.     

Analysis of copper grains in damascene trenches after rapid thermal processing or furnace anneals

The microstructures of Cu lines in damascene trenches annealed at temperatures from room temperature to 425°C using both rapid thermal processing (RTP) and furnace annealing were investigated using an array of characterization techniques including transmission electron microscopy (TEM), focused ion beam, scanning electron microscopy (SEM), and electron backscatter diffraction-orientation-imaging microscopy (EBSD-OIM). It was found that the final grain sizes strongly depend on the annealing process used; RTP generated larger grains than furnace annealing. The Cu line electrical resistance correlated with grain size differences observed for RTP and furnace anneals. The ramping rate, not the annealing time, played the critical role in the grain growth process. In either case, a high density of Σ3 coincident site lattice (CSL) twin boundaries was observed in the Cu lines. Forty-five percent of the grain boundaries measured were found to be Σ3 CSL twins, which are differentiated from random high-angle boundaries by having preferred electrical and diffusion properties. The minimum feature dimension of width or height of the damascene trenches limited the average grain size. Prior to the trench height limitation, the average grain size increased linearly with the trench width. The Cu (111) texture became stronger as the trench width increased up to 0.5 μm; for wider trenches, the texture did not increase further.     

Structure and electrical properties of polycrystalline SiGe films grown by molecular beam deposition

The structural and electrical properties of polycrystalline Si_0.5Ge_0.5 films 150 nm thick grown by molecular beam deposition at temperatures of 200–550°C on silicon substrates coated with amorphous layers of silicon oxynitride were studied. It is shown that the films consist of a mixture of amorphous and polycrystalline phases. The amorphous phase fraction decreases from ～50% in films deposited at 200°C to zero in films grown at 550°C. Subsequent 1-h annealing at a temperature of 550°C results in complete solid-phase crystallization of all films. The electron transport of charge carriers in polycrystalline films occurs by the thermally activated mechanism associated with the energy barrier of ～0.2 eV at grain boundaries. Barrier lowering upon additional annealing of SiGe films correlates with an increase in the average grain size.     

Effects of Substrate Bias on Microstructure of Osmium-Ruthenium Coatings for Porous Tungsten Dispenser Cathodes

Osmium-ruthenium (Os-Ru) films used as coatings for porous tungsten (W) dispenser cathodes were investigated in this study. By applying different levels of substrate biasing power during sputtering, the texture of deposited Os-Ru films varied between {0002}, {10-10}, and {10-11} in this hexagonal close-packed alloy. Furthermore, film texture changed from one preferred orientation to other preferred orientation(s) during annealing (at 1050^degC_B for 10 min), during which the microstructure of certain Os-Ru films changed from a columnar to an equiaxed grain morphology. Due to a low degree of texture transition during annealing and due to the high compositional and structural stability of the Os-Ru grains, a 5 W bias power appears to be best for film deposition. In addition, the 5 W biased Os-Ru films transformed completely into a basal plane texture, which has the highest planar density, and grain size increased significantly (from ~20 to ~100 nm) during annealing, all while maintaining a columnar grain structure. These characteristics are believed to be helpful in inhibiting interdiffusion between the W substrate and the Os-Ru film. Preventing or slowing the interdiffusion of W atoms can improve the lifetime and even the performance of dispenser cathodes.     

Solid-phase Crystallization of Hydrogenated Amorphous Silicon on Glass Substrates

Amorphous silicon films prepared by PECVD on glass substrate have been crystallized by conventional furnace annealing and rapid thermal annealing（RTA）, respectively. From the Raman spectra, X- ray diffraction and scanning electron microscope, it is found that the grain size is crystallized at 850 ℃ in both techniques. The thin film made by RTA is smooth and of perfect structure, the thin film annealed by FA has a highly structural disorder. An average grain size of about 30 nm is obtained by both techniques.