Microstructure evolution and mechanical properties of Ti-B-N coatings deposited by plasma-enhanced chemical vapor deposition

Ternary Ti-B-N coatings were synthesized on AISI 304 and Si wafer by plasma-enhanced chemical vapor deposition (PECVD) technique using a gaseous mixture of TiCl4,BCl3,H2,N2,and Ar.By virtue of X-ray diffraction analysis,X-ray photoelectron spectroscopy,scanning electron microscope,and high-resolution transmission electron microscope,the influences of B content on the microstructure and properties of Ti B N coatings were investigated systematically.The results indicated that the microstructure and mechanical properties of Ti-B-N coatings largely depend on the transformation from FCC-TiN phase to HCP-TiB2 phase.With increasing B content and decreasing N content in the coatings,the coating microstructure evolves gradually from FCC-TiN/a-BN to HCP-TiB2 /a-BN via FCC-TiN+HCP-TiB2/a-BN.The highest microhardness of about 34 GPa is achieved,which corresponds to the nanocomposite Ti-63%B-N (mole fraction) coating consisting of the HCP-TiB2 nano-crystallites and amorphous BN phase.The lowest friction-coefficient was observed for the nanocomposite Ti-41%B-N (mole fraction) coating consisting of the FCC-TiN nanocrystallites and amorphous BN

Characterization of Crystalline Nanoparticles/Nanorods Synthesized by Atmospheric Plasma Enhanced Chemical Vapor Deposition of Perfluorohexane

A mass of nanoparticles/nanorods were formed on a simultaneously deposited gran- ular film by plasma enhanced chemical vapor deposition （PECVD） of perfluorohexane at atmo- spheric pressure without any catalysts or templates. Scanning electron microscopy （SEM） and X-ray photoelectron spectroscopy （XPS） were used to characterize the morphology and the chem- ical compositions of nanoparticles. The average size of particles is about 100 nm and the length of synthesized nanorods is between 1 μm and 2.5/tm. The analyses of transmission electron microscopy （TEM）, high-resolution transmission electron microscopy （HRTEM）, selected area electron diffraction（SAED） and X-ray diffraction （XRD） reveals that the nanoparticles and nanorods are crystalline.

Hydrophobic Ti_xO_y-C_mH_n Nanoparticle Film Prepared by Plasma Enhanced Chemical Vapor Deposition

The hydrophobic films of TixOy-CmHn. deposited from mixture gases of titanium isopropoxide （TTIP） and oxygen by plasma enhanced chemical vapor deposition （PECVD） were investigated. The films were investigated by scanning electron microscope （ SEM ）, transmission electron microscope （ TEM ）, Fourier transform infrared spectrometer （ FTIR）, X-Ray diffraction （ XRD ）, element analysis （ EA ）, ultraviolet visible spectrometer （ UV-Vis）, and water contact angle （WCA）. The results reveal that the surface of the films is formed by mierosized papillaes aggregated by inorganic and organic phases of complex nanoparticles with size from 50 nm to 200 nm when the discharge power is increased from 40 W to 150 W. All fdms demonstrate the strong broad of Ti-O-Ti stretching vibration at 400 -800cm-1, -CH bending vibration at 1 388 cm -1, and broadening -OH stretching vibration at 3 000-3500 cm-1 With the increase of the discharge power, the asdeposited film changes from amorphous to crystallization. The WCA of the film can be as high as 160°, indicating the hydrophobicity. The films show a similar ultraviolet absorption property as the bulk TiO2 film. The composition of the composition of film deposited at 150 W can be formulated as Tio.302-C1.5H3. Therefore, the composition formula of this hydrophobic film could be expressed as TiO2-C5H10O4.7. It is believed that the complex micro/nano structures of TiO2 and C5H10O4.7 residues are responsible for the observed hydrophobicity and the ultraviolet absorption property of the film.

Direct low-temperature synthesis of graphene on various glasses by plasma-enhanced chemical vapor deposition for versatile, cost-effective electrodes

Catalyst-free and scalable synthesis of graphene on various glass substrates at low temperatures is of paramount significance to numerous applications such as low-cost transparent electronics and state-of-the-art displays. However, systematic study within this promising research field has remained scarce thus far. Herein, we report the direct growth of graphene on various glasses using a low-temperature plasma-enhanced chemical vapor deposition method. Such a facile and scalable approach guarantees the growth of uniform, transfer-free graphene films on various glass substrates at a growth temperature range of 400-600 ℃. The morphological, surface wetting, optical, and electrical properties of the obtained graphene can be tailored by controlling the growth parameters. Our uniform and high-quality graphene films directly integrated with low-cost, commonly used glasses show great potential in the fabrication of multi-functional electrodes for versatile applications in solar cells, transparent electronics, and smart windows.

Effects of various substrate materials on structural and optical properties of amorphous silicon nitride thin films deposited by plasma-enhanced chemical vapor deposition

The plasma-enhanced chemical vapor deposition(PECVD)technique is well suited for fabricating optical filters with continuously variable refractive index profiles;however,it is not clear how the optical and structural properties of thin films differ when deposited on different substrates.Herein,silicon nitride films were deposited on silicon,fused silica,and glass substrates by PECVD,using silane and ammonia,to investigate the effects of the substrate used on the optical properties and structures of the films.All of the deposited films were amorphous.Further,the types and amounts of Si-centered tetrahedral Si–SivN4-v bonds formed were based upon the substrates used;Si–N4 bonds with higher elemental nitrogen content were formed on Si substrates,which lead to obtaining higher refractive indices,and the Si–SiN3 bonds were mainly formed on glass and fused silica substrates.The refractive indices of the films formed on the different substrates had a maximum difference of0.05(at 550 nm),the refractive index of SiNx films formed on silicon substrates was 1.83,and the refractive indices of films formed on glass were very close to those formed on fused silica.The deposition rates of these SiNx films are similar,and the extinction coefficients of all the films were lower than 10-4.

Cleaning of nitrogen-containing carbon contamination by atmospheric pressure plasma jet

Atmospheric pressure plasma jet(APPJ)was used to clean nitrogen-containing carbon films(C–N)fabricated by plasma-assisted chemical vapor deposition method employing the plasma surface interaction linear device at Sichuan University(SCU-PSI).The properties of the contaminated films on the surface of pristine and He-plasma pre-irradiated tungsten matrix,such as morphology,crystalline structure,element composition and chemical structure were characterized by scanning electron microscopy,grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy.The experimental results revealed that the removal of C–N film with a thickness of tens of microns can be realized through APPJ cleaning regardless of the morphology of the substrates.Similar removal rates of 16.82 and 13.78μm min^(-1)were obtained for C–N films deposited on a smooth pristine W surface and rough fuzz-covered W surface,respectively.This is a remarkable improvement in comparison to the traditional cleaning method.However,slight surface oxidation was found after APPJ cleaning,but the degree of oxidation was acceptable with an oxidation depth increase of only 3.15 nm.Optical emission spectroscopy analysis and mass spectrometry analysis showed that C–N contamination was mainly removed through chemical reaction with reactive oxygen species during APPJ treatment using air as the working gas.These results make APPJ cleaning a potentially effective method for the rapid removal of C–N films from the wall surfaces of fusion devices.

SUBSTRATE EFFECT ON HYDROGENATED MICROCRYSTALLINE SILICON FILMS DEPOSITED WITH VHF-PECVD TECHNIQUE

Raman spectra and scanning electron microscope （SEM） techniques were used to determine the structural properties of microcrb＇stalline silicon （μc-Si：H） films deposited on different substrates with the very high frequency plasma-enhanced chemical vapor deposition （VHF-PECVD） technique. Using the Raman spectra, the values of crystalline volume fraction Xc and average grain size d are 86%, 12.3nm; 65%, 5.45nm; and 38%, 4.05nm, for single crystalline silicon wafer, coming 7059 glass, and general optical glass substrates, respectively. The SEM images further demonstrate the substrate effect on the film surface roughness. For the single crystalline silicon wafer and Coming 7059 glass, the surfaces of the μc-Si：H films are fairly smooth because of the homogenous growth or h＇ttle lattice mismatch. But for general optical glass, the surface of the μ-Si： H film is very rough, thus the growing surface roughness affects the crystallization process and determines the average grain size of the deposited material. Moreover, with the measurements of thickness, photo and dark conductivity, photosensitivity and activation energy, the substrate effect on the deposition rate, optical and electrical properties of the μc-Si：H thin films have also been investigated. On the basis of the above results, it can be concluded that the substrates affect the initial growing layers acting as a seed for the formation of a crystalline-like material and then the deposition rates, optical and electrical properties are also strongly influenced, hence, deposition parameter optimization is the key method that can be used to obtain a good initial growing layer, to realize the deposition of μc-Si：H films with device-grade quality on cheap substrates such as general glass.

Arc Discharge Device Working at Atmospheric Pressure

Arc in vacuum is one of the important methods used to prepare carbon materials. However, the use of vacuum increases the cost of the arc method. This paper introduces an arc discharge device working at atmospheric pressure. The current-limiting resistor, capacitor and inductor make the discharge gentle. The electrode temperature can be adjusted from 2040 K to 3673 K. Carbon nanofibres were prepared at the electrode temperature of 3645 K by using this device.

重掺硅片表面APCVD法生长SiO_(2)薄膜的致密性

在硅片加工过程中,金属杂质的存在会增大pn结器件的漏电流,甚至直接导致pn结禁带宽度变窄,为防止出现硅外延过程中造成的自掺杂现象,通常在硅片表面生长一层高致密性的SiO_(2)薄膜。基于常压化学气相沉积(APCVD)法在6英寸(1英寸≈2.54 cm)n型硅片表面生长SiO_(2)薄膜,首先研究不同沉积温度、SiH_(4)和O_(2)的体积流量比对沉积速率和SiO_(2)薄膜致密性的影响,进一步探究了不同退火温度对SiO_(2)薄膜致密性的影响,以期获得致密性较高的SiO_(2)薄膜。采用HF腐蚀速率法表征其致密性,采用扫描电子显微镜(SEM)观察SiO_(2)薄膜的表面形貌,采用F50膜厚测试仪测试SiO_(2)薄膜的厚度。结果表明,沉积温度为400℃,SiH_(4)和O_(2)的体积流量比为1∶10,退火温度为1100℃时,制备的SiO_(2)薄膜的致密性为0.096 nm/s(采用体积分数为1%的HF腐蚀)。

Effect of trace oxygen on plasma nitriding of titanium foil

Titanium nitride films are prepared by plasma enhanced chemical vapor deposition method on titanium foil using N_(2) as precursor. In order to evaluate the effect of oxygen on the growth of titanium nitride films, a small amount of O_(2) is introduced into the preparation process. The study indicates that trace O_(2) addition into the reaction chamber gives rise to significant changes on the color and micro-morphology of the foil, featuring dense and long nano-wires. The as-synthesized nanostructures are characterized by various methods and identified as TiN, Ti_(2) N, and TiO_(2) respectively. Moreover, the experiment results show that oxide nanowire has a high degree of crystallinity and the nitrides present specific orientation relationships with the titanium matrix.

APCVD法SiH_4-NH_3-CO_2系统制备氧氮玻璃薄膜的研究

在６６０℃下以ＳｉＨ４－ＮＨ３－ＣＯ２作为反应气体利用常压ＣＶＤ（ＡＰＣＶＤ）设备沉积得到了氧氮玻璃薄膜．此温度比文献报道的ＡＰＣＶＤ法低２００℃以上，有效地降低了沉积温度．实验发现ＮＨ３中水汽对沉积反应的显著影响．初步研究表明：运用ＡＰＣＶＤ法将这种薄膜应用于普通钠钙硅玻璃的表面改性。

铜基底上双层至多层石墨烯常压化学气相沉积法制备与机理探讨

化学气相沉积是目前最重要的ー种制备高质量、大面积石墨烯的方法.而铜是化学气相沉积法制备石墨烯中最常用的生长基底.虽然有大量文章报道了关于石墨烯的生长条件及生长机理,但是作为最广泛采用的材料,铜基底上双层及多层石墨烯的生长机理仍然在探索中,本文采用常压化学气相沉积法,以乙醇为碳源在铜基底上生长石墨烯,并将其转移到SiO_2/Si基底上.用场发射扫描电镜、透射电镜、拉曼光谱、光学显微镜对所制备的石墨烯进行表征和层数分析,对转移到不同基底上的不同层数的石墨烯进行了透光性分析.结果表明,常压条件下铜箔表面能够生长出质量较高、连续性较好的双层至多层石墨烯.此外,我们还对铜基底上双层至多层石墨烯的生长机理进行了探讨.

纳米多孔硅基薄膜的常压等离子体化学气相沉积过程研究

采用常压等离子体化学气相沉积(APECVD)的方法制备了带有新颖结构和特殊蓝紫光(400nm左右)发光特性的硅基薄膜.通过在自行研制的等离子体反应装置中通入按100∶1∶1的体积比进行配比的SiH4∶H2∶Ar混合气体进行APECVD,在加负偏压条件下获得了由Si基组成的絮状多孔纳米结构薄膜.通过等离子体发射光谱测定了沉积过程中的电子温度在2.2eV左右,扫描电子显微镜(SEM)观测薄膜表面形貌后肯定了偏压对薄膜纳米结构的形成起着重要的作用.

用常压化学气相沉积法制备SiO_2/S复合涂层的研究

以二甲基二硫(DMDS)和正硅酸乙酯(TEOS)为反应物,采用常压化学气相沉积法在HP40合金基体上成功制备了SiO2/S复合涂层。采用扫描电子显微镜(SEM)及其附带能谱仪(EDAX)、原子力显微镜(AFM)、X射线衍射(XRD)、Raman光谱等技术对涂层的形貌、元素成分、结构进行了表征,并对反应机理做了初步探讨。结果表明,SiO2/S复合涂层为无定形结构,主要由Si-O四面体的变形结构组成,S以S4及+4价状态与Si-O四面体的变形结构结合,涂层完整、致密。

氢气浓度对常压化学气相沉积ZrC涂层的影响

采用ZrCl4-CH4-H2-Ar体系在C/C材料基体上进行常压化学气相沉积(APCVD)制备碳化锆(ZrC)涂层。通过X射线衍射技术(XRD)和扫描电镜(SEM)对不同H2浓度下制备的ZrC涂层进行分析。对H2在沉积过程中的作用机制进行了讨论。结果表明:H2浓度对涂层的相组成、晶体的择优取向和结构形态有重要影响;无H2或H2浓度较低时,涂层含有大量的热解碳,由ZrC和碳两相组成,涂层呈多孔颗粒状;当H2浓度(体积分数)增加到30%以上时,涂层的相成分变为单一ZrC相;当H2的浓度增加到90%时,ZrC晶体取向由(111)、(200)转变为强烈的(220)择优取向,晶粒形貌变为纳米针状。

基底表面预氧化对SiO_2/S复合涂层的影响

为了减缓乙烯裂解炉管内表面的结焦，采用常压化学气相沉积方法，以二甲基二硫（DMDS）和正硅酸乙酯（TEOS）为先驱体。在预氧化的HP40合金试样上制备了SiO2／S复合涂层。分析了沉积温度、气体流速和沉积时间对涂层沉积速率的影响。利用扫描电镜、XPS和Raman光谱分别对涂层的形貌、成分和化学结构进行了表征，并对预氧化试样与涂层的结合进行了实验研究。结果表明，涂层主要由三节环Si2O-Si结构和Si-O-S结构组成，预氧化的试样涂层沉积速率是未氧化试样的2～3倍，试样氧化后涂层的抗热冲击性能和结合强度得到了提高。

化学气相沉积法制备纳微ZnO的实验和模拟研究进展

纳/微氧化锌材料性能优良,用途广泛,制备方法较多,其中化学气相沉积法(CVD)是较常用的方法之一。详细介绍了CVD方法制备纳米氧化锌的主要影响因素,概述了计算流体动力学(CFD)模拟在化学气相沉积法方面的应用和研究现状,并指出应该采用实验研究和计算模拟相结合的方法进行研究,利用计算模拟指导实验,从而实现纳微结构的可控生长。

退役炉管内表面二氧化硅涂层的制备及抗结焦性能研究

采用常压化学气相沉积法在退役Fe-Cr-Ni炉管内表面制备了SiO2涂层,对其抗结焦性能进行了研究。运用扫描电子显微镜和能量色散谱仪分析了原始退役炉管及SiO2涂层的表面形貌和组织结构;考察了在乙烯裂解的工艺条件下SiO2涂层的抗结焦能力,并对其抗热冲击性能进行了研究。结果表明,所制备的涂层表面完整、粒子结合致密,结焦试验2 h的结焦抑制率为70.6%;涂层可以经受7次900℃高温水冷热冲击试验。采用常压化学气相沉积法在炉管内表面制备SiO2涂层是行之有效的抑制结焦的方法。

晶相形成对TiSi_2薄膜光学性能的影响

通过常压CVD方法由SiH4和TiCl4直接在玻璃基板上成功制备了TiSi2薄膜，用XRD、FESEM、四探针测阻仪和分光光度计研究了薄膜的结构、形貌、电学和光学性能。研究表明TiSi2薄膜的晶相是面心正交刊TiSi2；薄膜的电阻率直接由晶相的形成决定，受晶相颗粒大小和晶相致密度控制，TiSi2薄膜的电阻率随薄膜中TiSi2晶相含量的增大而下降。TiSi2薄膜在400—750nm范围的可见光区具有大致相同的透射比和最小的反射比，薄膜的透射比随薄膜厚度的增加而减小。在大于750nm的红外区，薄膜电阻率越小，对红外辐射的反射比越高，且随着波长增加至25000nm，TiSi2薄膜的反射比逐渐上升到约0．95。

工艺参数对SiO2／S涂层形貌与结构的影响

为了抑制乙烯裂解炉管内表面结焦,采用常压化学气相沉积方法在HP40试样上制备了SiO2/S涂层。用SEM和Raman光谱研究了沉积温度、源物质分压以及气体流速对SiO2/S涂层形貌和结构的影响。结果表明随着沉积温度的增加,涂层组成粒子直径变化不大,粒子之间的结合更为致密,同时生成的三节环Si-O-Si结构逐渐增多,Si-O-S结构逐渐减少。气体流速与源物质分压对涂层粒子形貌的影响规律相似,随着各自参数的增加,涂层粒子逐渐增大,涂层更加致密。源物质分压和气体流速分别为40Pa和0.4m.s-1时,涂层中含有较多Si-O-S和三节环Si-O-Si结构。