电化学法制备BaMoO4和SrMoO4薄膜的生长特性比较研究(Ⅰ):共性分析

采用恒电流电化学技术直接在金属钼片上制备了具有白钨矿结构的钼酸盐（BaMoO4、SrMoO4）薄膜,对制备时间分别为10s直到50min的BaMoO4薄膜和制备时间分别为1min直到100min的SrMoO4薄膜的生长情况进行了SEM测试,并对相应结果进行了对比分析。研究表明：用电化学法制备BaMoO4和SrMoO4晶态薄膜,其生长特性既具有共性,也具有鲜明的个性。其共性特征是：1）成膜机制相同;2）薄膜生长初期就有比较完整的晶核生成;3）晶核和晶粒优先选择在金属基体缺陷（折叠、划痕、缺陷、凹凸不平等）处堆砌和生长;4）基体上晶粒的数量随着制备时间的增加而增加,晶粒的尺寸也随着时间的延长而长大,晶粒逐渐从稀疏分布到布满整个基体;5）在具有白钨矿结构的钼酸盐晶态薄膜的生长过程中,晶体的{111}面总是显露的。其鲜明的个性特征将在另文中讨论。该研究结果对功能晶态薄膜的生长（特别是利用电化学技术制备功能晶态薄膜的生长）和了解及预测自钨矿结构的晶态薄膜的生长习性,均具有重要意义。     

电化学法制备BaMoO_4和SrMoO_4薄膜的生长特性比较研究(II):个性研究

采用恒电流电化学技术直接在金属钼片上制备了具有白钨矿结构的钼酸盐(BaMoO4、SrMoO4)薄膜,对制备时间分别为10s直到50min的BaMoO4薄膜和制备时间分别为1min直到100min的SrMoO4薄膜的生长情况进行了SEM测试,并对相应结果进行了对比分析。研究表明:用电化学法制备BaMoO4和SrMoO4晶态薄膜,其生长特性既具有共性,也具有鲜明的个性。其共性特征已在另文中给出。其鲜明的个性特征是:1)BaMoO4和SrMoO4这两种薄膜在生长初期晶粒的成核速率不同;两种薄膜晶粒的生长速率不同;2)两种薄膜晶粒的形貌不同,晶粒的尺寸大小明显不同;3)两种薄膜晶粒的生长取向不同。该研究结果对功能薄膜的电化学制备和了解及预测白钨矿结构的晶态薄膜的生长习性,具有重要意义。     

电化学法制备BaMoO4和SrMoO4薄膜的生长特性比较研究(Ⅱ):个性研究

采用恒电流电化学技术直接在金属钼片上制备了具有白钨矿结构的钼酸盐（BaMoO4、SrMoO4）薄膜,对制备时间分别为10s直到50min的BaMoO4薄膜和制备时间分别为1min直到100min的SrMoO4薄膜的生长情况进行了SEM测试,并对相应结果进行了对比分析。研究表明：用电化学法制备BaMoO4和SrMoO4晶态薄膜,其生长特性既具有共性,也具有鲜明的个性。其共性特征已在另文中给出。其鲜明的个性特征是：1）BaMoO4和SrMoO4这两种薄膜在生长初期晶粒的成核速率不同;两种薄膜晶粒的生长速率不同;2）两种薄膜晶粒的形貌不同,晶粒的尺寸大小明显不同;3）两种薄膜晶粒的生长取向不同。该研究结果对功能薄膜的电化学制备和了解及预测白钨矿结构的晶态薄膜的生长习性,具有重要意义。     

电化学技术制备BaMoO4薄膜的初期生长特性

采用恒电流电化学技术直接在金属钼片上制备了具有白钨矿结构的钼酸盐(BaMoO4)薄膜.对BaMoO4薄膜进行了SEM测试,并对相应的测试结果进行了对比和分析.研究表明,在薄膜生长初期,其生长特性具有若干显著的特点,包括晶核和晶粒优先选择在基体缺陷处堆砌和生长;生长初期形成的晶核都具有白钨矿结构的骨架;晶核和刚开始长大生成的晶粒都是疏松的;晶粒都明显显示有蜂窝状空隙存在等.在薄膜生长的初始阶段,晶粒基本上以其c轴垂直于薄膜基体表面进行生长;随着薄膜制备时间的延长,晶粒的生长方向倾向于按其c轴在薄膜的表面内的方向进行生长.     

利用电化学技术制备白钨矿结构BaMoO4薄膜的成核和生长过程

采用恒电流电化学技术直接在金属铝片上制备了具有白钨矿结构的钼酸盐(BaMoO4)薄膜;通过EDX测试研究了该薄膜的成核和生长.研究结果表明,在薄膜生长的初期,一定数量的MoO4负离子配位多面体沉积在基片上并形成具有白钨矿结构的蜂窝状骨架,继而Ba2 对该蜂窝状骨架进行填充,由此形成晶核和晶粒;随着沉积时间的延长,蜂窝状结构不断长大,Ba2 离子也不断填充;当晶粒生长过程结束时,晶粒变饱满并且晶粒表面变光滑;当薄膜生长一定阶段时,晶粒及薄膜的组成符合其化学计量比.     

SrMoO4薄膜的化学溶液制备技术和发光性质研究

利用化学溶液技术制备了具有单一白钨矿结构的SrMoO4多晶薄膜.用X射线衍射仪(XRD)分析了薄膜的晶相结构,用红外光谱(IR)对薄膜的均一性进行了表征,用原子力显微镜(AFM)对薄膜的表面形貌进行了观察.采用荧光光谱仪测试了所制SrMoO4薄膜在不同温度下的光致发光特性.研究结果表明,在276 nm的紫外光激发下,钼酸锶薄膜室温条件下显示出良好的光致发光特性,呈现宽带(～300 nm)的发光特征.另外,光致发光光谱的峰值呈现出明显的温度漂移特性,从511 nm(11 K)变化到484 nm(293 K).此外,本文还讨论了SrMoO4薄膜在闪烁材料和紫外成像薄膜材料方面的可能应用.     

HiPIMS室温溅射晶态氧化铝薄膜的粒子能量调控EI北大核心CSCD

晶态氧化铝薄膜与非晶态相比,具有更加优良的力学性能和宽波段光学透过性能。基于等离子体发射光谱(OES)反馈控制方法(PEM),引入高能脉冲磁控溅射(HiPIMS)技术,实现了室温条件下晶态γ-Al_(2)O_(3)薄膜的快速制备。采用高压探针、电流探针传感器和数字示波器监测HiPIMS的放电特性,采用等离子体发射监测器进行时间平均的OES研究,采用X射线衍射仪和扫描电镜分析薄膜的晶相结构、晶粒尺寸及断面形貌,采用纳米压痕仪测试薄膜的纳米硬度和模量。结果表明,HiPIMS条件下的成膜环境出现大量的离子态,主要包括AlⅡ、ArⅡ甚至高价态粒子OⅣ参与反应。随着溅射电压由650V增加至800 V,晶粒逐渐细化,由18 nm减小到8 nm,同时沉积速率从27 nm/min增加到55 nm/min。基体偏压对薄膜的沉积速率,微结构以及力学性能等方面均有显著的影响。随着基体偏压的增加,γ-Al_(2)O_(3)的择优取向由(422)转变为(311),薄膜在偏压U_(s)=-100 V条件下获得了最高硬度19.3 GPa。通过对成膜粒子能量的设计与调控,进一步优化了薄膜的结构和性能,为功能薄膜氧化铝的大规模产业化奠定良好的应用基础。     

沉积时间对钼薄膜结构和热疲劳性能的影响

采用直流磁控溅射在不同沉积时间条件下制备钼薄膜,并用电子束热负荷装置对薄膜进行热疲劳性能试验,利用X射线衍射仪(XRD)对其结构和残余应力状态进行测试分析,用扫描电镜(SEM)对钼薄膜热疲劳前后形貌进行表征。结果表明:薄膜沿(110)取向择优生长,呈柱状晶结构,薄膜内存在张应力,残余应力随沉积时间增加而逐渐减小。热循环试验后均未出现薄膜脱落现象,但均产生表面裂纹。随着沉积时间由4h增加至8h,疲劳裂纹由穿晶断裂的直线裂纹转变为沿晶开裂的曲折裂纹,同时成膜过程中的退火效应使薄膜的晶粒长大、晶粒结构更加趋于完整、残余应力减小,从而使薄膜疲劳裂纹减小。     

反应磁控溅射沉积纳米多孔BiVO4薄膜光催化剂:总压力和基底的影响

使用脉冲直流电源、金属Bi和V靶材,在氩气和氧气气氛保护下,通过反应磁控溅射法在不同基板上沉积纳米多孔BiVO4薄膜,然后在空气中进行后退火处理,形成具有光敏性的单斜白钨矿晶体.研究总压力和基底对薄膜晶体结构、形貌、显微组织、光学和光催化性能的影响.结果表明,在石英玻璃基底上沉积的单斜白钨矿结构于250℃开始结晶,薄膜...     

BiVO_4/WO_3薄膜的原位相转换法制备及其光电化学性能研究

BiVO_4/WO_3异质结薄膜因其优异的光电催化活性,已成为光电催化领域的研究热点。然而,目前制备BiVO_4/WO_3异质结薄膜通常采用简单的沉积方法,制备的薄膜存在大量的晶隙和界面缺陷,不利于载流子在界面处的传输。本文利用WO_3→Bi_2WO_6→BiVO_4原位相转换的原理,成功制备BiVO_4/WO_3异质结薄膜。通过XRD和TEM等手段表征BiVO_4/WO_3异质结薄膜的结构,发现制备的薄膜存在晶隙和界面缺陷少的特点。以制备的薄膜为光阳极,通过光电化学测试,表明原位生长法制备的BiVO_4/WO_3薄膜的光电化学性能优于沉积法制备的BiVO_4/WO_3薄膜的,原位生长法制备的BiVO_4/WO_3薄膜的光电流密度达到0.32 mA/cm~2 (φ=1 V (vs. Ag/AgCl))。     

镁合金AZ31锰系磷化膜的生长过程及形成机理

以磷酸二氢锰的盐溶液为研究体系,采用SEM和EDS和电化学分析手段,研究镁合金AZ31锰系磷化膜的生长过程和形成机理。结果表明:磷化膜的生长过程分为5个阶段:基体溶解-成核阶段(0～130 s)、基体和磷化膜溶解阶段(130～630 s)、磷化膜快速生长阶段(630～1 300 s)、磷化膜稳态生长阶段(1 300～2 000 s)和磷化终止阶段(2 000 s以后)。磷酸盐晶核在镁合金AZ31浸入溶液的初始阶段一次形成,并优先在β相表面经过成核—长大—分裂—细化—增厚5个过程,沿表面方向生长和外延,最终形成致密的磷化膜。并且,磷化膜有两层,第一层是以Mg3(PO4)2和AlPO4以及MnHPO4为主的沉积薄膜;第二层则是在β相表面成核—长大的MnHPO4磷化膜。     

TC4表面沉积Nb涂层在模拟体液环境下的电化学性能研究

利用双阴极等离子溅射技术在Ti-6Al-4V (TC4)合金表面沉积Nb涂层,采用XRD、XPS和SEM研究涂层的组成及横截面形貌,并采用电化学工作站对涂层与基体的电化学性能及其钝化膜半导体特性进行研究.电化学测试均在模拟人体体液环境的Ringer's溶液中37℃下进行.结果 表明,Nb涂层厚度约为18 μm,无孔洞、...     

X-ray diffraction investigations of well-ordered sexithiophene films deposited on flexible substrates

Through optimizing deposition conditions such as substrate temperature and growth rate, well-ordered sexithiophene films were deposited on flexible substrates of insulating polyvinylpyrrolidone (PVP) and transparent conductive indium tin oxide (ITO). X-ray diffraction investigation showed that well-ordered sexithiophene films were deposited at substrate temperature of 90 °C and growth rate of 10 nm/min on PVP substrate with the main axis of sexithiophene molecules oriented parallel to the PVP surface and the crystallinity was declined with the decrease of substrate temperature. On ITO substrate, substrate temperature notably influenced the sexithiophene molecule orientation. There existed an inclined angle between the main axis of sexithiophene molecules and the ITO surface in the film deposited at room temperature. With the increase of substrate temperature, the main axis tended to parallel to the ITO surface and well-ordered sexithiophene film was deposited at 50 °C and 10 nm/min. Too slow or too rapid growth rate would lead to poor crystallinity of sexithiophene films on both PVP and ITO substrates.     

Growth of highly oriented Pt(100) thin films on a MgO(100) seed layer deposited on Si(100) substrates by rf magnetron sputtering

The growth of highly oriented Pt(100) thin films on Si(100) substrates deposited by rf magnetron sputtering was studied using a MgO(100) seed layer. The effects of the sputtering parameters on the growth of the MgO(100) seed layer were investigated in order to obtain the deposition condition which gives the best crystalline quality of (100) oriented MgO thin films. A highly crystallized MgO(100) film was obtained at a substrate temperature of 425°C, a rf power of 4.4W/cm² and a pressure of 12.5 mTorr. The crystalline quality of the MgO film was greatly decreased when the Si substrate was oxidized. The degree of (100) preferred orientation of the Pt film deposited on a MgO(100)//Si(100) substrate was found to be sensitive to the thickness of the MgO(100) seed layer, which is explained by the thickness dependence of the crystalline quality and the surface roughness of the MgO seed layer. A highly oriented Pt(100) film, for which the I₂₀₀/(_I200+I₁₁₁) ratio was about 0.8, was obtained at 550°C on a 50 nm thick MgO seed layer.     

紫外光辐照Bi_(4-x)Nd_xTi_3O_(12)薄膜制备工艺

以Pt(111)/Ti/SiO_2/Si为基片,采用溶胶凝胶法,通过紫外光辐照钕掺杂钛酸铋(Bi_(4-x)Nd_xTi_3O_(12), x=0.25, 0.75)胶体,分别采用电泳沉积和甩胶沉积制备薄膜,并对比了制备的薄膜质量.通过差热-热重分析(DSC-TG)、X射线衍射(XRD)、原子力显微镜(AFM)等技术手段对Sol-Gel法制备的BNT薄膜进行了表征.研究结果表明,经紫外光辐照和电泳沉积制备的Bi_(4-x)Nd_xTi_3O_(12) (x=0.25, 0.75) 薄膜于300 ℃煅烧有机物,500 ℃随炉热处理,可得到均匀致密且(117)择优取向的钙钛矿相BNT薄膜.     

The mechanism of low temperature deposition of crystalline anatase by reactive DC magnetron sputtering

It has been reported that TiO₂ film deposition by direct current (DC) magnetron reactive sputtering can occur according to the mechanism proposed by the theory of charged clusters (TCC). In the current study, the TCC was used to explain the mechanism of low temperature TiO₂ crystalline thin film growth. Highly oriented anatase thin films were deposited on unheated substrates. The degree of crystallinity of the thin film was found to depend on the cluster size and its crystallinity as well as the charging efficiency in the reactor. Larger clusters tend to be crystalline. These produce amorphous (nanocrystalline) films. Smaller clusters tend to be amorphous and adopt the structure of clusters already deposited to produce an ordered crystalline film. Increasing the substrate-to-target distance increased the cluster size. In addition, the charge density decreased as the target to substrate distance was increased. Clusters of <2 and 3 nm in diameter were observed at a substrate-to-target distance of 50 and 250 mm, respectively, which correspondingly produced crystalline and amorphous films. The DC power level did not appear to have a large effect on the cluster size nor did it affect the degree of crystallinity of the resulting thin film. The main factors affecting whether or not a crystalline film is deposited are the cluster size and the charge density in the reactor.     

Indentation and scratch tests on sputtered amorphous CN X films deposited on plasma-nitrided Ti-6Al-4V

Sputtered carbon nitride (CN _X ) films were deposited on both untreated and plasma-nitrided Ti-6Al-4V substrates. Surface and cross-section morphology of the deposited CN _X films was studied by scanning electron microscopy (SEM). Modified Vickers hardness tests showed that the intrinsic hardness of the CN _X film was about HV 2000 to 3000. Both the indentation and scratch tests showed that, compared with the CN _X film deposited on Ti-6Al-4V substrate, the load-bearing capacity of CN _X film deposited on a plasma-nitrided layer was improved dramatically. From the results of scratch tests, the duplex-treated system was effective in maintaining a favorable low and stable coefficient of friction and improving the wear resistance of Ti-6Al-4V substrate.