CVD温度对钽沉积层性能的影响

介绍了化学气相沉积(CVD)制备难熔金属钽涂层的原理及方法。采用冷壁式化学气相沉积法,在钼基体上沉积出难熔金属钽层。分析研究了CVD温度对沉积层的沉积速率、组织、结构和硬度等的影响。结果表明:在1000～1200℃温度范围,沉积速率随温度升高而增大;当温度超过1200℃时,沉积速率随温度的升高反而略有减小;沉积层组织呈柱状晶并随温度的升高逐渐增大;沉积层的硬度及密度随温度的升高而逐渐降低。化学气相沉积钽的最佳温度在1100℃左右。     

钽的CVD动力学规律及显微组织

简述氢气还原氯化钽化学气相沉积钽(CVD)的主要原理,研究氯化、氯气流量、氢气流量和沉积温度4个参数对沉积速率及沉积层显微组织的影响。结果表明:氯化温度对沉积速率的影响最小,沉积温度的影响最大;显微组织由小晶粒区和柱状晶区组成,沉积参数改变,柱状晶晶粒大小发生变化。     

等离子-物理气相沉积(PS-PVD)的材料输运行为与沉积机理研究进展EI北大核心CSCD

等离子-物理气相沉积(PS-PVD)具有制备层柱等多结构可控涂层的优异特性,但针对PS-PVD涂层结构调控的研究多局限于试错性试验,缺乏对涂层沉积与调控理论的研究,因此亟需对现有研究结果进行归纳、总结,以对PS-PVD沉积原理与涂层结构调控的进一步研究提供理论参考。针对PS-PVD所特有的涂层材料长距离输运、气液固多相态沉积过程,从涂层结构特征出发,综述PS-PVD沉积单元在经历喷枪内瞬时蒸发和喷枪外持续蒸发行为后,所进行的长距离输运行为与沉积行为的完整过程。此外,结合输运行为与沉积行为分析参数调控对沉积单元及涂层结构的影响规律,并对PS-PVD柱状结构涂层沉积机理的研究以及涂层制备技术的发展进行展望。     

退火处理及沉积方向对激光沉积TA15钛合金性能和组织的影响

以TA15钛合金粉末为原料,利用激光沉积制造方法制备TA15钛合金拉伸试样厚壁件。通过光学显微镜(OM)、扫描电子显微镜(SEM)和X射线衍射(XRD)等方法研究退火温度及沉积方向对TA15钛合金组织、拉伸性能的影响,以及α相变形机制。结果表明：随着退火温度升高,显微组织中α相长宽比呈上升趋势;激光沉积成形TA15钛合金厚壁件在沉积和垂直沉积方向上的力学性能存在差异,沉积方向上的抗拉强度明显均低于垂直沉积方向上的抗拉强度;柱状晶晶界对α片层的受力变形有一定的阻碍作用;α片层通过挤压变形和滑移变形两种机制发生变形或断裂;两种方向上拉伸断裂方式不同,沿沉积方向上断裂为韧性断裂,沿垂直沉积方向上断裂为半解理半韧性断裂。     

国内非晶态合金镀层研究动态

以９０年代国内公开发表的非晶态合金镀层的研究论文基础,综述该领域近期发展动态,指出非晶态合金以镍基合金度层为主,铁基合金镀层近期研究增多,其它合金镀层的研究逐渐增加,是国内研究的现状,但与日本相比,镀层种类仍较为单调,其工艺方法相对单一,尤其是化学镀更显滞后。     

电极力对Cr12MoV电火花沉积YG6工艺影响

电火花沉积工艺自21世纪初开发以来,由于放电时间短,沉积层结合力强,被广泛应用于材料延寿及表面改性等领域.文中利用自动电火花沉积系统,结合高速摄像技术、金相分析技术,研究了Cr12MoV模具钢沉积YG6工艺过程,分析了电极力对沉积表面粗糙度、沉积效率的影响规律.结果表明,电极力是影响沉积层质量与沉积效率的关键参数,通过反复试验得到该工艺中的最优电极力参数为1.6 N,在此参数作用下,电火花放电形成了火花放电为主与短路放电为辅的放电形式,沉积效率高,表面粗糙度低.     

Plasma Jet-Substrate Interaction in Low Pressure Plasma Spray-CVD Processes

Conventional equipment for plasma spraying can be adapted for operation at low pressure so that PECVD-like processing can be performed. The plasma jet generated by the torch is characterized by a high convective velocity and a high gas temperature. The influence of these properties on a deposition process are investigated in the framework of simple theoretical considerations and illustrated by various experimental results obtained with SiO _x deposition. A conclusion of this study is that the deposition process is dominated by diffusion effects on the substrate surface: the deposition profiles and the deposition rates are determined by the precursor density and by the gas temperature on the substrate surface. The high velocity of the jet does not play a direct role in the deposition mechanism. On the other hand it strongly increases the precursor density available for the deposition since it efficiently transports the precursor up to the substrate.     

阴极等离子体电解沉积工艺参数对放电与沉积过程的影响

为进一步认识和控制阴极等离子体电解沉积过程,研究了工艺条件对锌沉积时放电和沉积过程的影响,用扫描电镜和金相显微镜分别观察沉积层的表面和截面形貌,用能谱仪和X射线衍射仪进行沉积层元素和物相分析。结果表明,极间电压增大到约200V以上的某一电压值时阴极上发生等离子放电,初始放电电压与电解槽中的溶剂种类、氯化钠添加量有关,随乙醇和氯化钠添加量的增大而降低。要在阴极上实现锌的沉积,就应控制工艺条件使初始放电电压尽量低,且极间电压宜维持在初始放电电压以上10~20V。采用水和乙醇混合作溶剂比只用水作溶剂容易实现稳定的阴极沉积,沉积层厚度明显大,但沉积物表面的颗粒较粗大,致密性要差。     

药芯焊丝混合气体保护焊的熔敷特性研究

以Ar+CO2作为保护气体,研究了药芯焊丝混合气体保护焊的混合气体配比、焊接电流、电弧电压和气体流量对熔敷速度、熔敷系数和熔敷效率的影响。试验结果表明,Ar+CO2混合气体保护焊比CO2焊的熔敷效率高,Ar气比例达到60%以上,熔敷效率显著增加。焊接工艺参数选择合适时,可以获得较高的熔敷速度、熔敷系数和熔敷效率。     

OES monitoring of sequential deposition of C/W layers by PECVD/magnetron sputtering techniques

An innovative sequential plasma deposition method suitable for deposition of carbon/metal nanocomposite or multilayer films is presented. The method is based on cyclic exposure of a substrate, for predefined time intervals, to two totally independent plasma deposition sources, working in alternative sequences: magnetron sputtering (MS) for metal deposition and Plasma Enhanced Chemical Vapor Deposition (PECVD) for hydrogenated amorphous carbon (a-C:H) deposition. This paper presents a study of the a-C:H/W nanocomposite deposition method by optical emission spectroscopy (OES), focusing on identifying the useful wavelengths for optical monitoring of the process. On the basis of optical monitoring, the optimal pumping out and precursor gas admission conditions are established.     

脉冲真空电弧离子镀沉积速率的研究

薄膜沉积速率是影响薄膜性能的重要参数,研究它对于沉积优良的类金刚石薄膜具有重要的作用.针对脉冲真空电弧离子镀的具体工艺参数,研究了各种工艺参数对类金刚石薄膜沉积速率的影响,找出了影响类金刚石薄膜沉积速率的主要参数,得到了各种工艺参数下类金刚石薄膜沉积速率的曲线.     

Ti合金表面WC92-Co8电火花强化层形成规律

电火花强化技术可在Ti合金表面制造0．05mm以上的硬质合金强化层，彻底改变Ti合金表面性能。通过微分电火花强化过程，研究了单脉冲、多脉冲放电时强化点的形成规律；不连续、连续强化点的形成及最终形成一定厚度强化层的规律性。认为Ti合金表面的WC92-Co8强化层是通过无数次合金化过程实现的；基体的单脉冲强化点具有明显的“坑涌”现象。旋转的电极对熔池有搅动作用。     

Open-air laser-induced chemical vapor deposition of silicon carbide coatings

This study demonstrates the open-air deposition of amorphous hydrogenated silicon carbide (a-SiC:H) by laser-induced chemical vapor deposition (LCVD) using an enclosureless (open-air) reactor system. Films are deposited on fused quartz substrates using the precursor gas trimethylsilane (TrMS). Based on Auger electron spectroscopy (AES), Fourier transform infrared absorption spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), the film's chemical composition and microstructure is determined to be composed of a form of silicon carbide (SiC:H) with organic moiety. To understand the temperature-dependence of film growth during deposition, varying deposition conditions were employed to correlate the SiC film deposition rate and deposition temperature.     

沉积温度对高性能TiAlN涂层微观结构和力学性能的影响

采用真空电弧离子镀（AIP）技术在不同沉积温度下TiAlN涂层,用于高性能制造,并研究了沉积温度与表面性能的关系。结果表明,由于离子轰击作用,表面大颗粒随沉积温度的升高而减少。随着沉积温度的升高,涂层表面的晶粒尺寸先急剧减小后逐渐增大。此外,沉积温度对合成涂层的相组成和化学成分影响不大。随着沉积温度的升高,硬度和粘结强度先迅速增加,后逐渐降低。当沉积温度在450℃左右时,沉积的TiAlN涂层硬度最高,粘结强度最大。上述现象的发生机理与沉积过程中表面与界面之间的微观组织和残余应力的变化有关。合成的涂层在高达900℃的空气中具有良好的热稳定性。     

保护气氛中丝电爆喷射沉积工艺

开发了在保护气氛中丝电爆喷射沉积装置,在小直径圆柱体上选用纯铝丝进行电爆喷射沉积试验。分析沉积层形成过程中的影响因素与显微硬度。结果表明:在试验沉积距离下,宽度为3 mm的约束槽中发生电爆获得约4 mm宽的沉积层。整个圆柱面搭接沉积后,沉积层的厚度趋于均匀。当电容充电压为9 kV,铝丝直径为0.3 mm时,获得的沉积层的孔洞率最小、硬度值最高。沉积层中晶粒尺寸约为4 μm。     

反应磁控溅射法制备(Ti,Al)N薄膜的力学性能

以WF6和H2为原料,采用化学气相沉积法在纯铜基体上沉积出难熔金属钨涂层。分析研究了不同沉积温度(500℃,600℃,700℃)沉积层显微组织、表面形貌、表面粗糙度及相关机制。试验分析表明:随沉积温度升高,沉积速率加快,涂层组织柱状晶生长取向趋于杂乱;沉积层表面形貌发生明显改变,表面粗糙度显著增加。杂质颗粒对沉积组织有显著的影响,造成沉积表面粗糙度显著增加。     

Effects of deposition parameters on characteristics of carbon coatings on optical fibers prepared by thermal chemical vapor deposition

The effects of deposition parameters on characteristics of carbon coatings on optical fibers prepared by thermal chemical vapor deposition are investigated. The deposition parameters are selected as follows. The CH₄/(CH₄ + N₂) ratio is in the range between 20% and 100%; the temperature is set from 1173 to 1248 K; the working pressure is arranged between 50 and 100 kPa, and the residence time is ranging from 1.47 to 7.37 s. The deposition rate, microstructure, and electrical resistivity of carbon coatings are measured. The low-temperature surface morphology of carbon-coated optical fibers is elucidated. Experimental results indicate that the deposition rate increases with increasing the CH₄/(CH₄ + N₂) ratio, deposition temperature, working pressure, and residence time. The activation energy (= 456 kJ/mol) of carbon deposition from methane was shown to correlate to the activation energy of methane dissociation. The deposition rate is proportional to about first-order of partial pressure of methane, and thus, the deposition process is mainly controlled by the process to create mono-carbon species in the carbon film. As the deposition rate increases, the size and number of particles on the carbon coating surface and electrical resistivity of carbon coatings increase, while the ordered degree, nano-crystallite size, and sp² carbon atoms of the carbon coatings decrease. Additionally, the low-temperature surface morphology of carbon coatings shows that as the carbon coating thickness is large enough to sustain the thermal loading, decreasing the deposition rate is good for producing hermetic optical fiber coatings.     

工艺参数对钨丝表面无氰镀金质量的影响

为了实现钨螺旋线表面镀金薄膜质量可控,研究了无氰电镀过程中工艺参数如电流密度、镀液温度和沉积时间对镀金层质量的影响规律。利用扫描电子显微镜对镀金层形貌进行观察分析。结果表明:电流密度影响镀金薄膜的表面平整度及晶粒大小;镀液温度影响无氰镀液稳定性,从而影响薄膜的表面光泽度及平整度;电沉积时间对镀层覆盖效果影响较大。沉积时间过短,镀层覆盖效果差;时间过长,边角效应严重。沉积时间宜控制在1.5 h内。     

沉积温度及其变化对金刚石膜内黑色缺陷产生过程的影响

用高功率直流电弧等离子体喷射方法研究金刚石膜沉积温度稳定性对膜中黑色缺陷产生的影响。结果表明,在温度稳定条件下制备的金刚石膜中,黑色缺陷的密度较低;当沉积温度大幅度变化时,在膜中产生大量黑色缺陷。形成大量黑色缺陷的原因是:沉积温度变化时,在金刚石晶粒的表面形成贯穿型孪晶,而在随后的生长过程中,这些孪晶的长大将抑制金刚石膜局部生长环境中活化的反应气体与其下晶界位置的金刚石组织接触,导致其生长缓慢并保留在金刚石膜中,从而形成大量黑色缺陷。     

Displacement deposition of gold nanoparticles and electroless deposition of nickel films on silicon-carbide (4H-SiC) wafers

Metallisation of silicon carbide (SiC) wafers is a key technology for producing efficient power devices. Conventional autocatalytic electroless deposition cannot produce adherent metal films directly on SiC substrates. The authors applied their recently developed surface-activation process for electroless metal-film deposition on silicon wafers to SiC wafers. Gold nanoparticles were produced on 4H-SiC substrates by displacement deposition after immersing the substrates in a tetrachloroauric(III) acid solution that includes hydrofluoric acid or potassium hydroxide. The size and the particle density of the deposited gold are changed with deposition parameters such as the surface condition of the substrates, the solution composition, and the UV-light illumination. The gold nanoparticles work not only as catalysts to initiate autocatalytic electroless deposition but also as binding-points between the metal film and the SiC surface. Adherent and uniform nickel-phosphorus alloy films are produced on such SiC substrates by autocatalytic electroless deposition without any further treatments.