大规模真空蒸镀二氧化钛薄膜及其表征

采用大型真空镀膜设备在玻璃基底上蒸镀二氧化钛(TiO2)薄膜,并对TiO2薄膜进行了SEM、AFM、XRD、紫外可见光吸收光谱、亲水性的测试及分析,探讨了退火温度对薄膜性能的影响.结果表明制备的TiO2薄膜具有良好的均匀性.在室温条件下,TiO2薄膜具有无定型的结构;在300～500℃的条件下,TiO2薄膜退火2h后以锐铁矿晶型为主,600℃退火的TiO2薄膜明显向金红石型转变.随退火温度的升高,薄膜对紫外光和可见光的吸收有明显提高,并出现了明显的红移现象.另外,亲水性也随退火温度的升高而变强,500和600℃退火的TiO2薄膜表面出现超亲水性.     

改性纳米TiO_2薄膜超亲水性的研究进展

纳米TiO2超亲水薄膜是新型的功能性薄膜,在自洁、防雾和生物兼容性应用等方面起着重要的作用。由于普通的TiO2薄膜禁带宽度较大,亲水性能不佳,使其实际应用受到极大的限制,改性是提高TiO2薄膜超亲水性能的重要手段。因此,对TiO2进行改性就成为该领域的关键课题之一。文中综述了纳米TiO2薄膜的超亲水性机理,以及实现超亲水性表面的改性方法。     

退火温度对纳米TiO2薄膜结构和亲水性的影响

采用射频磁控溅射方法制备出纳米二氧化钛(TiO2)薄膜,研究了不同退火温度对薄膜微观结构和超亲水性的影响.结果表明:退火温度升高,晶粒长大,孔隙率减小;常温制备300 ℃以下退火的TiO2薄膜为无定形结构,亲水性差;400 ℃～650 ℃退火的薄膜为锐钛矿结构,表现出超亲水性;800 ℃退火薄膜为金红石结构,亲水性有所下降.     

电子束蒸镀快速沉积铜膜研究

利用电子束蒸镀设备沉积金属薄膜是微电子领域最常见的薄膜沉积工艺之一。然而使用普通钨坩埚电子束蒸镀铜薄膜时,沉积速度非常低。这是因为熔融的铜与钨坩埚是浸润的,当提高电子枪功率时,液态铜的表面自由能随着温度的升高而降低,液态铜会沿着坩埚壁向上铺展,消耗电子束能量。为此,对钨衬埚壁进行结构优化,阻止了电子枪功率较高时液态铜的向上铺展,将铜膜的沉积速度从2?/s提高到20?/s,并对不同沉积速率制备的铜薄膜的粗糙度、均匀性、应力进行对比,验证了该方法的可行性。     

有机玻璃基材表面电子束蒸镀铬-铝-二氧化硅薄膜及其性能研究

采用电子束蒸镀的方法,以有机玻璃为基材,在其表面蒸镀铬过渡层,再蒸镀铝,最后蒸镀保护层二氧化硅.实验结果表明:增加铬过渡层的样品,铝膜结合的非常牢固,附着力得到很大的提高.和未蒸镀二氧化硅保护层的样品进行耐腐蚀性测试对比,发现二氧化硅薄膜具有很好的保护性,铝膜在10%的碱性溶液中完好无损;而没镀二氧化硅保护层的样品,铝膜很快溶解.试验结果表明,采用电子束蒸发技术,在使用合适的工艺参数下,可以在有机玻璃表面制备附着力好、耐腐蚀的高反射铝膜.     

钛合金表面高温真空蒸镀钛涂层的组成和结构

对钛合金表面高温真空蒸镀钛涂层进行了研究,并将钛合金表面蒸镀层及附近的组成和结构与未作蒸镀处理的钛合金的组成和结构作了对比分析,对经蒸镀处理后的钛合金试样表面元素含量的变化作出了初步的解释。     

电子束辐照对HDPE结构与亲水性能影响的研究

研究了在空气中电子束辐照所引起的ＨＤＰＥ分子结构变化以及辐照对ＨＤＰＥ亲水性的影响”。结果表明,通过电子束辐照可在ＨＤＰＥ分子链上引入含氧极性基团,使的表面自由能增大,极性增强,与水的接触角减小。辐照ＨＤＰＥ的分子量降低,分子量分布变窄。     

蒸镀TiO2薄膜的面料

采用真空蒸镀法制备了负载纳米TiO2织物。利用扫描电镜（SEM）和X射线衍射仪（XRD）分别分析了其表面形貌和晶体结构,探讨了负载TiO2和热处理对棉织物的抗紫外线性能的影响。萁结果表明：在蒸镀条件相同的前提下,蒸镀时间为13s且经过热处理的负载纳米TiO2织物的抗紫外线性能较好。     

使用PEM监控制备光致亲水性TiO2薄膜的研究

本文采用中频反应磁控溅射方法在玻璃表面制备了TiO2薄膜,为使反应溅射的工作点能够稳定在“过渡区”,得到较高的薄膜沉积速率,使用了等离子体发射光谱监控法（Plasma Emission Monitor,PEM）对溅射过程进行控制。利用台阶仪测膜厚,用X射线衍射（XRD）和透射率光谱扫描等测试方法对薄膜的特性进行表征。对制得的薄膜进行了光照试验,研究了温度、PEM工作点等不同工艺条件对薄膜亲水性的影响。薄膜经过1 h左右的紫外光照射,得到了很好的亲水性效果,其表面的水接触角达到了小于1°的水平。将薄膜经过光照后再置于黑暗中一段时间,如此循环了5次,仍具有很好的光致亲水效果,证明此过程是可以循环重复的。     

H2O+ O2气氛下电子束蒸镀制备MgO介质保护膜特性研究

采用电子束蒸镀法在H2O+ O2气氛下制备了MgO介质保护膜,通过扫描电镜、X射线衍射(XRD)等方法分析了MgO薄膜的表面、截面形貌与晶体结构,研究了不同H2O流量下得到的MgO薄膜对等离子屏放电特性的影响。结果表明:MgO薄膜呈柱状结构,随H2O流量增加MgO晶粒尺寸变大、晶界减少;XRD分析结果显示H2O+ O2气氛下,MgO薄膜除(111)晶面择优取向外,还出现了(220)晶面取向;H2O气氛的通入降低了等离子屏的维持电压、改善了放电裕度,同时缩短了寻址放电延迟时间,有利于等离子屏节能降耗和实现快速寻址。     

电子束蒸发法制备TiO2薄膜的折射率研究

用电子束蒸发法制备TiO2薄膜,并对其进行300℃、400℃、850℃热处理和掺杂.详细研究了工艺参数、热处理和掺杂对TiO2薄膜折射率的影响.实验结果表明:镀制高折射率的氧化钛薄膜最佳工艺参数为基片温度200℃、真空度2×10-2 Pa、沉积速率0.2 nm/s;随着热处理温度的升高,薄膜折射率也逐渐增大;适量掺杂CeO2(CeO2:Ti0质量比1.7:12)会提高薄膜的折射率,过量掺杂CeO2反而会降低折射率.     

离子辅助蒸发(1-x)TiO2-(x)Ta2O5薄膜及其光学性能研究

采用离子辅助蒸发的方法，以不同配比的Ta2O5和TiO2混合物为初始膜料在K9玻璃上制备了TiO2-Ta2O5混合薄膜，并对其透射性能和光学常数进行研究。实验结果表明，薄膜在可见光范围内的平均透射率在82％以上，并随着Ta2O5含量的增加而增加；薄膜的折射率在1．80～2．07范围内变化（550nm）。对同-Ta2O5含量的薄膜来说，退火后TiO2薄膜和80TiO2—20Ta2O5薄膜的折射率较退火前提高，而90TiO2-10Ta2O5薄膜的折射率较退火前降低。     

Studies on tin oxide films prepared by electron beam evaporation and spray pyrolysis methods

Transparent conducting tin oxide thin films have been prepared by electron beam evaporation and spray pyrolysis methods. Structural, optical and electrical properties were studied under different preparation conditions like substrate temperature, solution flow rate and rate of deposition. Resistivity of undoped evaporated films varied from 2.65 × 10⁻² ω-cm to 3.57 × 10⁻³ ω-cm in the temperature range 150–200°C. For undoped spray pyrolyzed films, the resistivity was observed to be in the range 1.2 × 10⁻¹ to 1.69 × 10⁻² ω-cm in the temperature range 250–370° C. Hall effect measurements indicated that the mobility as well as carrier concentration of evaporated films were greater than that of spray deposited films. The lowest resistivity for antimony doped tin oxide film was found to be 7.74 × 10⁻⁴ ω-cm, which was deposited at 350°C with 0.26 g of SbCl₃ and 4 g of SnCl₄ (SbCl₃/SnCl₄ = 0.065). Evaporated films were found to be amorphous in the temperature range up to 200°C, whereas spray pyrolyzed films prepared at substrate temperature of 300– 370°C were poly crystalline. The morphology of tin oxide films was studied using SEM.     

Structural and optical properties of electron beam evaporated CdSe thin films

Thin films of cadmium selenide (CdSe) as a semiconductor is well suited for opto-electronic applications such as photo detection or solar energy conversion, due to its optical and electrical properties, as well as its good chemical and mechanical stability. In order to explore the possibility of using this in optoelectronics, a preliminary and thorough study of optical and structural properties of the host material is an important step. Based on the above view, the structural and optical properties of CdSe films have been studied thoroughly in the present work. The host material, CdSe film, has been prepared by the physical vapour deposition method of electron beam evaporation (PVD: EBE) technique under a pressure of 5 × 10⁻⁵ mbar. The structural properties have been studied by XRD technique. The hexagonal structure with a preferred orientation along the (0 0 2) direction of films has been confirmed by the X-ray diffraction analysis. The films have been analysed for optical band gap and absorbed a direct intrinsic band gap of 1·92 eV.     

新型Ti-650合金电子束焊接头组织及性能研究

采用电子束对新型耐650 ℃使用的高温钛合金板材进行焊接,并进行1 000 ℃/1 h/AC+700 ℃/4 h/AC的退火处理,研究了接头的组织、硬度分布,母材和接头的拉伸性能和持久性能.结果表明,接头组织由α相、少量β相、以及大量细小的再结晶α相构成.接头中母材、热影响区和焊缝的显微硬度值比较均匀,介于440~490HV之间.室温条件下,母材和接头的抗拉强度均高于1 000 MPa,延伸率均介于7%~10%;650 ℃拉伸,母材抗拉强度达到了750 MPa,延伸率最高达20%;接头的抗拉强度在700 MPa以下,延伸率在10%~14%之间.接头与母材的持久断裂均是由孔洞聚集形成微裂纹,在力的作用下不断扩展,直至最终断裂.而接头中柱状晶的晶界促进了裂纹的扩展,所以母材的持久寿命和应变优于接头.根据结果分别得出了650 ℃下接头和母材应力与寿命的关系式.     

Optical and structural properties of ZnO/TiO2/ZnO multi-layers prepared via electron beam evaporation

We prepared a ZnO/TiO₂/ZnO multi-layer on quartz glass substrate via electron beam evaporation. Optical and structural properties of the ZnO/TiO₂/ZnO multi-layer were investigated. The TiO₂ buffer layer is found to improve the crystallinity of the ZnO thin film. A green emission of the ZnO thin film deposited on the TiO₂ buffer layer was significantly enhanced due to the increased defect concentration of oxygen vacancy. Photoluminesence spectra measured at 9 K revealed that a violet luminescence at 409 nm was attributed to the draft of the donor's defect levels in the ZnO thin film.     

电子束选区熔化成形Ti_(2)AlNb合金微观组织与性能EI北大核心CSCD

Ti_(2)AlNb基合金由于具有优异的高温比强度、高温抗蠕变性能和较高的断裂韧度,因而被认为是替代传统镍基高温合金最具潜力的材料。采用电子束选区熔化(selective electron beam melting,SEBM)技术成形Ti-22Al-25Nb合金,通过工艺优化获得高致密度(5.42-5.43 g/cm^(3))的成形试样。研究了沉积态和热等静压(hot isostatic pressing,HIP)态试样的显微组织演变、物相演变及其对力学性能的影响。结果表明:沉积态和HIP态组织呈现出沿成形方向的柱状晶结构,且均由B2,O和α_(2)相组成,沉积态试样中的O/α_(2)相自上而下逐渐增加,HIP后组织趋于均匀化,且相对沉积态,析出相的宽度缩小、数量减少。沉积态试样中析出相较多的下部区域具有更高的显微硬度((345.87±5.09)HV),HIP后试样硬度值增加至388.91-390.48HV。沉积态试样室温抗拉强度和伸长率分别为(1061±23.71)MPa和(3.67±1.15)%,HIP后抗拉强度增加至(1101±23.07)MPa,伸长率降低至3.5%。     

电子束熔炼制备块体钨的组织与显微硬度研究

钨材料具有极高的熔点,传统上采用粉末冶金方法制备,获得的钨材料具有晶粒细小、微观组织均匀等优点, 但致密性不足。为进一步提升钨材料的性能,本研究将98.3%的钨粉和1.7%的碳粉均匀混合,在1 800 ℃、26 MPa条件下热压成型,而后采用电子束熔炼技术对成型后的钨块进行熔炼,利用金相显微镜、SEM、显微硬度计等对其显微组织、致密度和显微硬度进行评价,并与传统粉末冶金法制备的块体钨的性能进行了对比。结果表明:电子束熔炼制备的钨锭冶金质量好,致密度可达99.8%;试样的显微硬度达到9.16 GPa,显著高于粉末冶金法制备的块体钨材料,突破了热压烧结工艺制备块体钨的致密度-显微硬度的关系;经1 300 ℃、6 h退火热处理后,显微硬度略有下降,但仍达到8.86 GPa,显示出电子束熔炼技术在制备块体钨硬度性能方面的优势。     

Investigation of spitting behaviour of NiCoCrAlY type materials during electron beam evaporation

ABSTRACT

Spitting behaviour of four casted and powder metallurgy ingots used in the fabrication of NiCoCrAlY-type environmental protective coatings by electron beam physical vapour deposition was investigated and correlated with ingot microstructures and compositions. Spits found in the coatings mainly consisted of the Ni₅Y phase precipitated in the β-NiAl matrix while their typical size exceeded 50?µm. Spitting was less pronounced for ingots having a higher Cr content, larger size of γ-Ni(Co, Cr) precipitates formed within β-NiAl grains and narrower transitional zone formed at the interface between molten and unmolten ingot regions and consisting of coarsened β grains. Large (above 100?µm) agglomerates of the Ni₅Y phase detected below the zone were identified as the main spit precursors.     

Comparison study of microstructure, chemical composition and optical properties between resistive heating and electron beam evaporated LaF3 thin films

LaF₃ thin films were deposited by electron beam (EB) and resistive heating (RH) evaporation, respectively. Properties such as microstructure, chemical composition, surface morphology and optical constants of the LaF₃ thin films were characterized by measurements of X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy and spectrophotometer, then comparison was made between this two deposition methods. It's found that the microstructure properties of the LaF₃ films deposited by these two methods were different, and slight content of oxyfluoride films was formed during deposition according to the result of chemical composition analysis. The microstructure of LaF₃ bulk materials after interaction with electron beam and resistive heating was also characterized to analyze how the two deposition processes affect the formation of LaF₃ thin films and their microstructure properties. When it was for the laser resistance of the films, although the EB evaporated LaF₃ thin films occupied lower absorption and optical loss than those of the RH films, they showed slightly smaller laser induced damage thresholds at 355 nm, which was thought to be related to their much more rougher surface and higher tensile stress.