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。     

高温高压水中镍基合金表面氧化膜的原位表面增强型拉曼光谱

采用表面增强型拉曼光谱方法原位研究了镍基合金在高温高压水环境中的腐蚀行为及其表面生成氧化膜.Ni-5Cr-8Fe表面氧化膜的拉曼光谱存在三个拉曼峰,位于540 cm-1,610 cm-1和670 cm-1.610 cm-1峰的出现表明了氧化膜中存在Cr2 O3.540 cm-1峰则说明氧化膜中含有Cr2 O3或NiO或两者的混合物.670 cm-1峰对应于FeCr2O4尖晶石的生成.Ni-10Cr-8Fe的表面氧化膜由Cr2 O3、FeCr2O4构成,可能含有一定的NiO.Ni-10Cr和Ni-20Cr的表面氧化膜主要为Cr2 O3,没有发现尖晶石相的存在.随着合金中铬含量的增加,表面氧化膜中Cr2O3的含量增加,NiO成分减少.     

膜厚对四面体非晶碳薄膜机械性能和拉曼表征的影响

采用过滤阴极真空电弧技术以相同的工艺条件在单晶硅衬底上制备了不同厚度的四面体非晶碳薄膜.利用表面轮廓仪测试薄膜的厚度和应力,利用纳米压入仪测试薄膜的硬度、弹性模量和临界刮擦载荷,利用可见光拉曼光谱表征薄膜的结构.试验结果表明:随着膜厚的增加,薄膜的应力持续降低,当膜厚超过30 nm时,应力低于5 GPa;当膜厚超过300nm时,硬度和弹性模量分别接近70 GPa和750 GPa,十分接近体金刚石的性能指标;随着膜厚的增加,可见光拉曼光谱中衬底硅的一阶和二阶谱峰强度逐渐降低,但非晶碳一阶谱峰的最大峰强、峰位和半高宽有特定的变化规律;峰位逐渐向低频偏移,在50～80 nm膜厚范围,半高宽最窄,峰强最高.     

液相电化学法在不锈钢上沉积类金刚石薄膜

采用直流脉冲电源,以甲醇有机溶液作为碳源,通过电化学沉积法在不锈钢表面制备了类金刚石碳(DLC)薄膜.用扫描电镜和拉曼光谱分析了薄膜的形貌和结构,用MTS纳米压痕仪测试DLC薄膜的硬度和Young's模量,在CERT微摩擦系统上测试了薄膜的摩擦学性能.结果表明:电化学沉积含氢类金刚石碳薄膜的硬度较高(约7GPa),薄膜均匀、致密,表面粗糙度小;拉曼光谱在1332.51 cm-1处出现金刚石的特征峰;在室温干摩擦条件下,薄膜同WC钢球对摩时的摩擦系数随载荷增加而略微减小,抗磨性能则随着载荷的增加而变差,对摩时发生转移并形成转移膜,耐磨寿命缩短.     

直流电弧等离子体喷射化学气相沉积法制备金刚石膜过程中冷阱的设计及作用

首先,介绍直流电弧等离子体喷射化学气相沉积法的原理以及气体循环系统的设计和其优缺点;其次,详细介绍冷阱系统的设计及其工作原理;最后,使用拉曼光谱和傅里叶变换红外光谱与光致发光光谱对比添加冷阱系统前后的金刚石薄膜的质量。结果表明：冷阱系统可以有效过滤循环气路中的热油气,避免杂质的掺入;在添加冷阱系统后,金刚石膜内掺入的杂质减少,金刚石拉曼峰半高宽降低到6.76 cm-1,接近于Ib型单晶金刚石的,且自支撑金刚石膜的晶体质量明显提高,光学透过率提升较大,在10.6μm波长处达到68.4%。     

316L不锈钢表面沉积类金刚石膜的拉曼光谱分析及润湿性研究

采用等离子体辅助化学气相沉积(PECVD)法,在316L不锈钢基体表面以不同的沉积气压和射频功率制备出类金刚石(DLC)薄膜.拉曼光谱分析结果表明:所沉积的DLC膜具有典型的类金刚石膜结构,薄膜中sp#键含量随工艺参数的不同而不同,射频功率100 W时,sp#键含量随沉积气压增高而降低.接触角测试结果表明:DLC膜沉积...     

MPCVD装置基片台改进对金刚石薄膜均匀性的影响

通过对实验室自主研发的10 k W新型微波等离子体装置基片台的改进,获得了更高的基片温度,更长的保温时间以及更均匀的基片温度。用直径为80 mm的硅片在改进后的基片台上用MPCVD法沉积大面积金刚石膜。在微波功率为5 k W,沉积气压为5.6 k Pa环境下基片中心获得900℃的基片温度,沉积时间8 h。实验后对硅片中央区域,距离中心20 mm区域,距离基片中心35 mm区域进行对比分析,通过SEM显示三个区域金刚石膜的表面形貌差异很小,通过拉曼光谱观察到在1 332 cm-1处代表金刚石相的特征峰无明显的变化从而确定可金刚石膜在质量上的均匀性,最后对金刚石的厚度表征发现所观察的区域内膜厚变化保持在0.2⁰.4μm之间且金刚石呈现柱状生长模式。     

以新型硼源制备硼掺杂金刚石膜的性能研究

采用微波等离子体化学气相沉积技术,以氧化硼-乙醇溶液作为硼源,制备不同掺硼浓度的金刚石膜。利用扫描电子显微镜、X射线衍射仪、激光拉曼光谱仪、电化学工作站等研究其表面形貌、晶体结构、薄膜质量和电化学性能。结果表明:随硼元素含量升高,金刚石膜的晶体颗粒尺寸先减小后增大,电势窗口由3.1V降至2.6V,阳极电流密度由0.022 7mA·cm-2降至0.011 9mA·cm-2,但对背景电流及电化学可逆性几乎不影响。      

强激光冲击合成超细金刚石

利用强激光冲击处理合成了金刚石微晶，通过拉曼光谱和扫描是民镜分析了产物的成份和粒度，讨论了其转变机理。     

钢基阳极氧化膜的制备与表征

目的在碳钢表面制备阳极氧化膜,探讨阳极氧化膜的成分组成。方法采用恒电流阳极氧化法在含0.1 mol/dm~3 NH_4F和0.5 mol/dm~3 H_2O的乙二醇电解液中,于45#钢表面制备阳极氧化膜。通过SEM、EDS、XPS、Raman、IR、动电位极化测试等技术手段表征所制备的阳极氧化膜。结果所获阳极氧化膜外观为黄色。电流密度为1 A/dm~2时,氧化膜局部区域出现彩虹色;电流密度为1.5 A/dm~2时,氧化膜颜色较均匀。随着氧化时间的增加,氧化膜颜色变深。阳极氧化膜表面具有特征图案。EDS分析发现,阳极氧化膜中存在Fe、O、C。XPS分析进一步表明,阳极氧化膜中还含有F元素。Fe2p XPS谱的各项数据均与α-Fe_2O_3的较为吻合。拉曼分析表明,电流密度为1.5 A/dm2的阳极氧化膜的拉曼光谱的峰的数量多于电流密度为1 A/dm~2的。所有氧化膜的拉曼光谱均在1400 cm~(-1)附近有峰出现,此峰对应于α-Fe_2O_3。700 cm~(-1)处的峰对应于FeOOH。红外光谱分析表明,所有阳极氧化膜的红外光谱波形一致,在700~400 cm~(-1)之间出现振动,540、514、482 cm~(-1)附近的吸收峰归属于Fe_2O_3的振动带,604、672 cm~(-1)的吸收峰归属于FeOOH。极化测试表明,经阳极氧化处理后,自腐蚀电位上升,自腐蚀电流密度降低。结论碳钢能够在乙二醇体系电解液中生成黄色阳极氧化膜。电流密度和氧化时间对膜的颜色有影响。膜表面具有特征图案。阳极氧化膜主要含Fe、O、F等元素。Fe元素以Fe(Ⅲ)的化学态形式存在于阳极氧化膜中。阳极氧化膜中氧化物主要为α-Fe_2O_3,FeOOH也存在其中。阳极氧化处理后的试样的耐蚀性较处理前有所提升。     

High-temperature oxidation behavior of nanocrystalline diamond films

In this study, high-temperature stability of nanocrystalline diamond films prepared by hot filament chemical vapor deposition (HFCVD) was investigated through differential thermal analysis/thermal gravimetric analysis (DTA/TGA), thermal analyses, visible and UV Raman analysis, and XPS analysis. Nanocrystalline diamond films with crystalline size of about 25 nm were obtained, which possess high density of grain boundaries with a high sp²-bonding of non-diamond carbon. In the initial stage of oxidation, grain boundaries with non-diamond carbon and graphite phase were preferentially etched away by oxygen, which carries on with a faster rate. Then, a slower oxidation rate was continued through reacting the carbon atoms in rigid diamond structure with oxygen. The activation energies for former and the latter, calculated from the thermal analysis, are 195 and 217 kJ/mol, respectively. Both the results of in-situ Raman spectra and XPS spectra indicate that the carbon with sp²-bonding significantly decreased with increasing temperature and soaking time.     

CVD掺硅金刚石残余应力的X射线衍射和拉曼光谱分析(英文)

采用X射线衍射(XRD)和拉曼光谱2种方法测量了不同硅碳比的CVD掺硅金刚石薄膜的残余应力。采用偏压增强热丝化学气相沉积装置在硬质合金基底上制备了掺硅金刚石薄膜,将正硅酸乙酯以不同的体积比溶解在丙酮中以使得反应气体中的硅碳比从0.1%变化到1.4%,从而控制掺硅金刚石薄膜的掺杂浓度。SEM和XRD的表征结果显示,随着硅掺杂浓度的增加,金刚石薄膜的晶粒尺寸减小,而金刚石(110)的晶面则逐渐占优。XRD法是测量入射角从0°到45°变化时对应的金刚石(220)面XRD衍射峰,并采用sin2ψ方法计算掺硅金刚石薄膜的残余应力。拉曼谱法则是通过检测金刚石特征峰偏移1332cm1位置的偏移量来测量残余应力。2种方法测得的残余应力随着硅掺杂含量的升高显示出良好的一致性,所有的硅掺杂金刚石的残余应力均为压应力,Si/C摩尔比为0.1%的薄膜具有最高的残余应力,为~1.75GPa(拉曼谱法)或~2.3GPa(XRD法)。随着硅掺杂浓度的进一步升高,薄膜的残余应力则稳定在~1.3GPa左右。     

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.     

Study on morphologies and structures of diamond films synthesized on cemented carbide substrates

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Preparation of free-standing diamond films for high frequency SAW devices

Free-standing diamond films were prepared by hot filament chemical vapor deposition (HFCVD) method under different conditions. Inter-digital transducers (IDTs) were formed on the nucleation sides of free-standing diamond films by photolithography technique. Then piezoelectric ZnO films were deposited by radio-frequency(RF) reactive magnetron sputtering to obtain the ZnO/diamond film structures. Surface morphologies of the nucleation sides and the IDTs were characterized by means of scanning electron microscopy (SEM), atomic force microscope (AFM) and optical microscopy. The results indicate that the surfaces of nucleation sides are very smooth and the IDTs are of high quality without discontinuity and short circuit phenomenon. Raman spectra show the sharp diamond feature peak at about 1 334 cm⁻¹ and the small amount of non-diamond carbon in the nucleation side. X-ray diffraction (XRD) patterns of the structure of ZnO/diamond films show a strong diffraction peak of ZnO (002), which indicates that as-sputtered ZnO films are highly c-axis oriented.     

硅掺杂CVD金刚石薄膜

研究硅掺杂对CVD金刚石薄膜形貌、结构特性和成分的影响。通过向丙酮中加入正硅酸乙酯作为反应气体,在硅基底上沉积硅掺杂CVD金刚石薄膜。金刚石薄膜的表面形貌和显微组织由场发射电镜表征。金刚石薄膜的成分通过拉曼光谱和X射线衍射（XRD）进行研究。薄膜的表面粗糙度由表面轮廓仪评估。结果表明,硅掺杂会降低晶粒尺寸,促进晶粒细化并抑制三角锥形形貌。XRD研究表明,（111）朝向的晶面显著减少。拉曼光谱研究表明,硅掺杂会促进薄膜中硅碳键的形成以及非金刚石相的增多。在硅碳浓度比为1％时,沉积得到光滑的细晶粒金刚石薄膜。     

Fe-B-C体系金刚石单晶的高温高压制备与表征

在国产六面顶高温高压设备上,利用低价纯铁粉末为触媒开展含硼金刚石的制备研究。研究发现:无定型硼的掺入会导致金刚石合成条件(温度和压力)不断提高;晶体颜色由浅黄色逐渐变为黑色,晶体主要以八面体为主。利用扫描电镜(SEM)分析含硼金刚石的微观形貌,发现:硼添加后金刚石{111}晶面上存在微米尺寸的圆形凹坑。通过Raman光谱研究发现:随着硼掺入量的增加,金刚石特征峰发生蓝移,其半峰宽变大、晶体质量下降。通过红外光谱可以发现较强的Ⅱb型金刚石存在2 800 cm-1处的 B-C键特征峰。在纯铁触媒体系中,硼的质量分数在0.2%～0.8%时,均能合成出优质含硼金刚石。      

Effect of high temperature annealing on ultrahard polycrystalline diamond in air and vacuum conditions

The effect of high temperature annealing on ultrahard polycrystalline diamond (UHPCD) has been investigated in air and vacuum conditions up to 1500 °C. The thermal stability, carbon bonds, morphologies and wear resistance of UHPCD were evaluated by thermal gravimetric-differential scanning calorimetry (TG-DSC), Raman spectroscopy, scanning electron microscopy (SEM) and wear tester. The thermal analysis results indicated that the thermal stability of chemical vapor deposited (CVD) diamond was better than that of polycrystalline diamond (PCD) even though it was weakened by high pressure high temperature treatment, while no graphitization was observed on UHPCD in flowing argon up to 1500 °C. When the UHPCD annealed in air, the oxidation damage with the extension of cracks and spalling holes was observed on CVD diamond as the evolution of temperature. The result confirmed by the changes of diamond peak position and full width at half maximum (FWHM) in Raman spectra curves. The PCD had shown the damage with cracks induced exfoliation of binder regions and cracks ruined diamond grains. However, the diamond peak position and FWHM of CVD diamond and PCD showed slight reduction as a function of vacuum annealing temperature with no detectable change of morphologies. The high temperature annealing has strong impact on the wear resistance of UHPCD in air while slightly in vacuum.     

Magnesium interlayered diamond coating on silicon

Diamond thin films have been deposited using hot filament chemical vapour deposition technique on manually scratched p-Si(1 0 0) substrate, with and without magnesium interlayer. In spite of magnesium melting point being lower (T_m = 649 °C) than the growth temperature of the substrate (T_s  750 °C) used in these experiments, it was found that high quality diamond films could be grown on Mg covered substrate. A liquid substrate is probably generated during the diamond film growth. Raman spectroscopy analysis exhibited only the triply degenerate, zone centre optical phonon peak at 1333 cm⁻¹ indicating that nearly stress free crystallites were present. Broadening of the Raman peak (11.76 cm⁻¹) indicates that some small crystallites also are present. Scanning electron and atomic force microscopy accompanied by X-ray diffraction analysis where used to compare the details of diamond film growth directly on scratched Si(1 0 0) and Mg interlayered scratched Si(1 0 0) substrates.     

单颗钎焊金刚石磨粒磨损试验研究

采用单颗磨粒试验方法,以碳钢碟轮为修整工具,研究金刚石和CBN磨粒修整过程中的磨损特征。结果表明:砂轮和修整碟轮的相对速度对金刚石磨粒的磨损有重要影响;相对速度为51.9 m/s时,金刚石磨粒的磨损高度为50.1 μm;相对速度为17.3 m/s时,金刚石磨粒的磨损高度显著减小,为19.5 μm。通过相同条件下金刚石与CBN磨粒的磨损特征对比,表明金刚石磨粒在磨损过程中同碟轮之间发生化学作用,加速金刚石磨粒的磨损;对试验后金刚石磨粒进行拉曼光谱分析,并未检测到石墨物质。