基体负偏压对四面体非晶碳膜结构和性能的影响

采用自主研制的45°单弯曲磁过滤阴极电弧沉积系统于Si基体表面制备了四面体非晶碳(ta-C)膜,研究了基体负偏压对薄膜沉积速率、成分、力学性能及摩擦学性能的影响规律。结果表明,随基体负偏压升高,ta-C膜sp3键含量呈先增后减的变化趋势,在-50V时达到最大值(约64%);其硬度和弹性模量呈相似的变化规律,在-50V偏压下获得最大值(48.22GPa和388.52GPa)。ta-C薄膜的摩擦学性能与其sp3碳杂化键的含量密切相关,在-50V偏压下制备的薄膜具有最小平均摩擦因数值(0.10)。可见,采用单弯曲磁过滤阴极弧电弧制备ta-C薄膜的力学和摩擦学特性主要受薄膜中sp3键含量的制约。     

基体负偏压对四面体非晶碳膜结构和性能的影响

采用自主研制的45°单弯曲磁过滤阴极电弧沉积系统于Si基体表面制备了四面体非晶碳(ta–C)膜,研究了基体负偏压对薄膜沉积速率、成分、力学性能及摩擦学性能的影响规律。结果表明,随基体负偏压升高,ta–C膜sp3键含量呈先增后减的变化趋势,在-50 V时达到最大值（约64%）;其硬度和弹性模量呈相似的变化规律,在-50 V偏压下获得最大值(48.22 GPa和388.52 GPa)。ta–C薄膜的摩擦学性能与其sp3碳杂化键的含量密切相关,在-50 V偏压下制备的薄膜具有最小平均摩擦系数值（0.10）。可见,采用单弯曲磁过滤阴极弧电弧制备ta–C薄膜的力学和摩擦学特性主要受薄膜中sp3键含量的制约。     

过滤阴极真空电弧制备非晶金刚石红外保护膜

采用过滤阴极真空电弧技术,通过施加不同衬底偏压制备了非晶金刚石薄膜.利用纳米压痕仪和光谱椭偏仪测试薄膜的力学性能和光学性能,利用KLA-Tencor台阶仪测试硅衬底在薄膜沉积前后的曲率半径,并根据Stoney方程计算薄膜应力,利用可见光拉曼光谱和电子能量损耗谱研究了薄膜的微结构.实验表明:当衬底负偏压为80 V时,薄膜的硬度、弹性模量、光学带隙和折射率均达到最大值,随着偏压的升高或降低,各参量分别降低;此时,薄膜的sp3杂化含量最高,斜坡系数却最小;在宽红外波段范围内,薄膜的消光系数趋近于零,即红外透明;另外,薄膜具有接近金刚石的高硬度和高模量,并且其微结构以及光学和力学性能可调,因此是一种优异的红外光学窗口增透保护薄膜材料.     

偏压对四面体非晶碳膜结构和性能的影响

目的 通过系统研究电弧离子镀偏压对四面体非晶碳膜(ta-C膜)结构及性能的影响规律,阐明偏压对ta-C膜结构及性能的影响机制,为拓展ta-C膜的应用提供一定的理论依据.方法 改变电弧离子镀偏压工艺,在硬质合金基体表面沉积ta-C单层膜.采用场发射扫描电子显微镜(SEM)表征ta-C膜表面及截面显微形貌,采用Raman光...     

刻蚀工艺对四面体非晶碳膜生长及其性能的影响

目的研究不同等离子体刻蚀工艺对基体和四面体非晶碳膜(ta-C)的影响,并进一步考察不同电弧等离子体刻蚀时间对ta-C薄膜结构的影响。方法采用自主设计研制的45°单弯曲磁过滤阴极真空电弧镀膜设备,进行不同等离子体刻蚀以及ta-C薄膜的沉积。使用等离子体发射光谱仪表征离子种类及其密度,使用椭偏仪表征薄膜厚度,原子力显微镜表征刻蚀后的基体粗糙度,拉曼光谱仪和XPS表征薄膜结构,TEM分析薄膜的膜基界面结构。结果辉光刻蚀工艺中,作用的等离子体离子以低密度的Ar离子为主;而电弧刻蚀时,作用的等离子体离子为高密度的Ar离子和少量的C离子,并且能够在基体表面形成约15 nm的界面层,并实现非晶碳膜(a-C)的预沉积。随电弧等离子体刻蚀时间增加,ta-C薄膜的sp3含量有所降低。结论相比于辉光刻蚀,电弧刻蚀利于制备较厚的ta-C薄膜。这主要是因为电弧刻蚀时,基体表面形成良好的界面混合层,并预沉积了非晶碳膜,形成a-C/ta-C的梯度结构,有助于增强膜基结合力。     

拉曼光谱表征无氢类金刚石薄膜的新方法

DLC薄膜的拉曼光谱表征主要依靠D峰和G峰的强度比值(ID/IG)来定性判断sp3含量,但当sp3所占百分比高于20%时,ID/IG值对sp3含量的变化不敏感,判断的误差很大.采用直流磁控溅射和多弧离子镀制备了一系列无氢DLC薄膜样品,并测量了样品的拉曼光谱和维氏硬度.通过数据分析,发现薄膜硬度和拉曼光谱中的G峰半峰宽具有很好的相关性,因而提出通过G峰半峰宽来定量判断DLC薄膜中sp3含量的拉曼光谱表征新方法.     

金刚石薄膜缺陷的激光拉曼光谱分析

本文分析了不同基板温度下在单晶硅衬底上沉积的金刚石薄膜的激光拉曼光谱特征。根据这些拉曼光谱的特点,讨论了金刚石膜中存在的几种缺陷,如内应力、SP~2态碳等。此外,对金刚石膜作光荧光分析表明,金刚石膜还存在点缺陷,如中性空缺,其零声子线(ZPL)位于1.677eV处。     

Nb对Zr基块体非晶合金热稳定性、非晶形成能力及机械性能的影响

利用水冷铜模铸造法成功制备了(Zr70Ni10Cu20)90-xNbxAl10(x=0,2,5,7)块体非晶合金,采用XRD,DSC和DTA研究了Nb对该合金体系热稳定性和非晶合金形成能力(GFA)的影响．结果表明,适量Nb的添加可有效提高该合金的GFA和热稳定性．当Nb含量为x=2时,合金具有最宽的过冷液态区(△Tx=119K)和最大的非晶形成能力(参数γ=Tx／(Tg T1)=0．435),Nb的适量添加也有利于提高块体非晶合金的强度和塑性应变,其中x=2的块体非晶的抗压强度和断裂应变量分别达到1783MPa和11．1％。     

掺磷四面体非晶碳薄膜的电学性能

采用过滤阴极真空电弧技术以PH_3为掺杂源,施加0—200 V基底负偏压,制备了掺磷四面体非晶碳(ta-C:P)薄膜,利用X射线光电子能谱(XPS)和Raman光谱研究ta-C:P薄膜的微观结构,通过测定变温电导率和电流-电压曲线,考察ta-C:P薄膜的导电行为。结果表明,磷掺入增加了薄膜中sp~2杂化碳原子含量和定域电子π/π~*态的数量,提高了薄膜的导电能力,且以-80 V得到的ta-C:P薄膜导电性能最好,在293—573 K范围内ta-C:P薄膜中的载流子表现出跳跃式传导和热激活传导两种导电机制,电流-电压实验证明ta-C:P薄膜为n型半导体材料。     

过滤式阴极电弧沉积类金刚石薄膜工艺的研究

本文研究了过滤式阴极电弧沉积系统的稳弧工艺参数,通过正交试验获得最佳稳弧参数,并且研究了弯管内置挡板对宏观粒子过滤效果的影响,采用喇曼光谱研究了偏压对生成的类金刚石薄膜性能的影响,证明－１００Ｖ偏压下,获得的类金刚石薄膜有最佳的ｓｐ＾３含量,扫描电镜测试表明,在（１１１）硅基片上获得致密的膜,但在高速钢基体上沉膜堆积现象比较严重,不易获得优质类金刚石膜。     

Mechanical properties and Raman characterization of amorphous diamond films as a function of film thickness

Amorphous diamond (a-D) films with different thicknesses have been prepared on the c-Si substrate under the same deposition conditions using filtered cathodic vacuum arc (FCVA) technology. The film thickness was measured with a calibrated surface profiler. The mechanical properties were analyzed by a nano-indenter and the microstructure was characterized with visible Raman spectroscopy. It has been shown that the residual compressive stress of a-D films drops continuously down with increasing film thickness. When the films are thinner, the stress falls strikingly. However, the falling rate is less pronounced with the monotonic increase in film thickness. Hardness and Young's modulus also persistently rise with growing film thickness. Whereas the critical scratching load decreases at first and then increases again. The peak position of the asymmetric broad peak in the Raman spectra shifts towards low frequencies with increasing film thickness because of the monotonic fall in the residual compressive stress. However, the magnitude of the shift is smaller. Additionally, the Raman characterization is apt to be taken in the film thickness scope of 50-80 nm.     

Effects of sample thickness on microstructures and mechanical properties of A357 alloy

Abstract

The effects of sample thickness on the density, microstructures and mechanical properties of as cast Al alloy were investigated. Microstructures were observed with a scanning electron microscope. Mechanical properties were studied at room temperature. The results show that the sample thickness has minor influence on the relative density of Al alloy. The obtained relative density up to ～99·24% was confirmed that the vacuum counter–pressure casting has the excellent solidification mechanism. The microstructures were refined and the secondary dendrite arm spacing was decreased with the decrease in sample thickness, and the ultimate tensile strength, yield strength and elongation were improved. The ultimate tensile strength and elongation could be related to their secondary dendrite arm spacing using linear equations. With the increase in sample thickness, the quasi-cleavage fractures were increased and the number of dimples got an evident reduction in fracture surfaces.     

金刚石(膜)的拉曼光谱表征技术进展

本文较全面地介绍了金刚石(膜)拉曼光谱中各主要拉曼峰的位置、特点及光致发光现象,重点对1150 cm-1附近拉曼峰产生的原因进行了讨论.通过对前人数据、结论的分析,指出1150 cm-1附近的散射峰和紫外拉曼光谱中T峰出现的机理应是一致的,都源于有序尺寸的减少.根据共振尺寸选择效应,1150 cm-1附近的拉曼峰,可能是紫外拉曼光谱中的T峰在可见光谱中向高波数移动的结果;而不同方法制备的金刚石膜样品其晶粒尺寸差异造成的振动模禁止,是不同研究者对1150 cm-1附近拉曼峰作为纳米晶金刚石的特征峰争论的原因所在.     

Ellipsometric analysis and optical absorption characterization of nano-crystalline diamond film

A nano-crystalline diamond （NCD） film with a smooth surface was successfully deposited on silicon by a hot filament chemical vapor deposition （HFCVD） method. Scanning electron microscopy （SEM）, atomic force microscopy （AFM）, RAMAN scattering spectra, as well as spectroscopic ellipsometry were employed to characterize the as-grown film. By fitting the spectroscopic ellipsometric data in the energy range of 0.75-1.50 eV with a three-layer model, Sildiamond＋non-diamondldiamond＋ non-diamond＋voidlair, the optical constants are obtained. The refractive index of the NCD film varies little from 2.361 to 2.366 and the extinction coefficient is of the order of 10^-2. According to the optical transmittance and absorption coefficient in the wavelength range from 200 to 1 100 nm, the optical gap of the film is estimated to be 4.3 eV by a direct optical transition mechanics.     

Ag和Fe元素添加对Cu-Zr-Al系非晶形成能力和力学性能的影响

以Cu-Zr-Al三元系为基础,研究Ag和Fe合金组元添加对块体金属玻璃(BMG)及BMG基复合材料的非晶形成能力和力学性能的影响.在Cu-Zr-Al三元合金体系中,Cu50Zr42Al8系BMG的△Tx=61 K,Trg=0.624,γ=0.416.适量添加Ag元素能显著地提高非晶形成能力:在Cu-Zr-Al-Ag四元合金体系中,Cu43Zr45Al8Ag4、Cu45Zr42Al8Ag5、Cu40Zr44Al10Ag6、Cu43Zr41Al8A98和Cu36Zr48Al8Ag8的Trg分别为0.618、0.625、0.618、0.628和0.598,γ值分别为0.424、0.427、0.424、0.432和0.433,△TX分别为77、76、78、84和108 K.在(Cu0.36Zr0.48-Al0.08Ag0.08)100-XFex(x-=0,3,5,10,15,20)五元体系中,Fe的添加明显影响合金的非晶形成能力;尽管△TX和Trg呈下降趋势,但(Cu0.36Zr0.48Al0.08Ag0.08)97Fe3块体非晶合金仍具有较高的非晶形成能力,其△TX=103 K,Trg=566,γ=0.424:Fe的适量加入可显著提高合金的力学性能,其中(Cu0.36Zr0.48Al0.08Ag0.08)95Fe5合金的强度和塑性应变分别提高至2 249 MPa和4.9%.Fe元素的存在导致Cu36Zr48Al8Ag8合金中产生明显的相分离,使(Cu0.36Zr0.48Al0.08Ag0.08)100-xFex合金得到增强增韧.     

铜基体预沉积铜-金刚石复合过渡层金刚石膜的制备与表征（英文）

在铜基体表面电沉积铜-金刚石复合过渡层,采用电镀铜加固突出基体表面的金刚石颗粒,最后利用热丝化学气相沉积(HFCVD)法在复合过渡层上沉积大面积的与基体结合牢固的连续金刚石膜。采用扫描电子显微镜、拉曼光谱和压痕试验对所沉积的金刚石膜的表面形貌、内应力及膜/基结合性能进行研究。结果表明:金刚石膜由粗大的立方八面体颗粒与细小的(111)显露面颗粒组成,细颗粒填充在粗颗粒之间,形成连续的金刚石膜。复合过渡层中的露头金刚石经CVD同质外延生长成粗金刚石颗粒,而铜表面与粗金刚石之间的二面角上的二次形核繁衍长大成细金刚石颗粒。金刚石膜/基结合力的增强主要来源于金刚石膜与基体之间形成镶嵌咬合和较低的膜内应力。     

反应气体对纳米金刚石薄膜的显微力学特性影响

本文采用电子辅助增强热丝化学气相沉积(HFCVD)系统,CH4/H2、CH4/H2/Ar气体和不同比例的四种气氛制备了纳米金刚石薄膜,利用Raman光谱和原子力显微镜(AFM)表征了薄膜的结构和显微形貌,采用纳米压入测试技术测量了纳米金刚石薄膜的显微力学特性,获得了加载、卸载曲线,以及硬度和模量随压入深度的变化曲线。结果表明:薄膜具有明显的纳米结构特点,随着CH4、Ar浓度的增加,晶粒更加细化,表面粗糙度更低。无Ar气氛制备的纳米金刚石薄膜的弹性恢复较好,硬度和模量较高,CH4和Ar含量越低的制备气氛,其硬度和模量相对较高。     

Effects of the substrate on the determination of thin film mechanical properties by nanoindentation

We examine the effects of the substrate on the determination of mechanical properties of thin films by nanoindentation. The properties of aluminum and tungsten films on the following substrates have been studied: aluminum, glass, silicon and sapphire. By studying both soft films on hard substrates and hard films on soft substrates we are able to assess the effects of elastic and plastic inhomogeneity, as well as material pile-up, on the nanoindentation response. The data set includes Al/glass and W/sapphire, with the film and substrate having nearly the same elastic properties. These systems permit the true contact area and true hardness of the film to be determined from the measured contact stiffness, irrespective of the effects of pile-up or sink-in. Knowledge of the true hardness of the film permits a study of the effects of the elastic modulus mismatch on the nanoindentation properties, using the measured contact stiffness as a function of depth of indentation.     

AZ31镁合金沉积Mg-Cu-Y非晶薄膜的结构与性能

采用非平衡磁控溅射方法在AZ31镁合金表面沉积Mg-Cu-Y薄膜,以纯铜和Mg65Cu25Y10合金作为溅射靶材,选则Mg65Cu25Y10单靶、Mg65Cu25Y10靶和铜靶双靶两种方式分别进行溅射沉积。利用XRD、AFM、SEM分析了膜层结构与表面形貌,纳米压痕法、球盘式摩擦磨损测试研究了膜层的硬度和耐磨性。结果表明,Mg65Cu25Y10单靶溅射得到的薄膜为完全非晶态结构,而双靶共溅获得的膜层中出现含有铜的晶态组织。随着膜层中Cu含量的增加,纳米硬度较非晶态膜层有所降低,但同时耐磨性提高。两类不同结构薄膜相比较,Mg65Cu25Y10单靶溅射沉积的非晶膜层硬度最高,达到12GPa。用磨损量评价了基体与膜层的耐磨性,包含Cu结晶相的双靶共溅薄膜具有较好的耐磨性能。     

沉积参数对Mo-Re合金基体上沉积金刚石薄膜的影响

采用热丝化学气相沉积法(HFCVD),以甲烷和氢气为反应气体,在综合性能良好的Mo-40%Re(摩尔分数)合金基体上沉积金刚石薄膜.采用X射线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)和显微激光拉曼光谱仪(Raman)分别对金刚石薄膜相组成、表面形貌、晶粒大小和质量等进行检测分析,研究CVD沉积参数,如基体温度(θs)、碳源浓度(R,Cn4的体积分数)和沉积压强(p),对金刚石形核、生长和金刚石成膜的影响.结果表明在合适的基体预处理条件下,当θs=750℃,R=-3%,p=3.5kPa时,薄膜平均线生长速率高达1μm/h,得到的金刚石膜完整致密,晶粒大小均匀,纯度较高,具有明显的(111)织构.