不同沉积温度下CrCN涂层的力学性能

使用磁控溅射技术在304不锈钢表面制备CrCN涂层,研究了沉积温度(200、250、300、350和400 ℃)对涂层结构及力学性能的影响。研究表明,沉积温度为250 ℃时,涂层的晶粒尺寸及表面粗糙度最大,但随着沉积温度的进一步升高,涂层的晶粒逐渐细化,表面粗糙度明显下降;同时涂层硬度伴随沉积温度的升高出现先增大后减少的趋势,沉积温度为350 ℃时,薄膜具有最高的硬度(22.85 GPa),抗弹性形变和抗塑性形变能力最好,体现出优异的力学性能。     

CVD温度对钨沉积层组织性能的影响

以WF6和H2为反应气体,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.分析研究了沉积温度对沉积层组织、结构、表面形貌及涂层致密度、硬度、耐磨性能的影响.试验结果表明:随着温度升高,沉积速率加快,涂层组织逐渐由柱状晶转变为树枝晶,表面粗糙度显著增加,膜层致密度、硬度下降,耐磨性降低.化学气相沉积钨的最佳工艺温度范围为550～650℃.     

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。     

沉积温度对CrB_2涂层结构与性能的影响

为了研究沉积温度对涂层微结构与力学性能的影响,采用直流磁控溅射技术制备了CrB_2涂层。通过XPS、XRD、SPM、SEM、HRTEM、纳米压痕仪和维氏压痕仪分别分析了涂层的成分、结构、微观形貌和力学性能。结果表明:在不同沉积温度下,CrB_2涂层均由CrB_2和少量Cr相组成。涂层具有致密的纳米柱状结构,其直径大约为7nm,且沿着生长方向贯穿整个涂层截面。随沉积温度升高,涂层晶体取向由(101)和(001)的混合取向逐渐转变为(001)择优取向,涂层由纤维状结构转变为柱状晶结构,且柱状晶尺寸随沉积温度的增加逐渐细化,致密化程度增加。涂层的力学性能随沉积温度的升高而显著增加;当沉积温度达到400℃时,涂层具有最高硬度(50.7±2)GPa和最高弹性模量(513.6±10)GPa。微观结构和力学性能随沉积温度的演变归因于沉积原子运动的逐渐增强和结构的致密化。     

沉积温度对电弧离子镀AlCrSiN涂层的影响

目的 优化涂层制备工艺,改善AlCrSiN涂层的力学及摩擦性能。方法 采用可调节磁场强度的新型电弧离子镀技术,在不同沉积温度下研制AlCrSiN涂层。利用XRD及SEM分析AlCrSiN涂层的相结构、截面形貌,借助纳米压痕仪、划痕测试仪、高温摩擦磨损试验机以及台阶仪测试AlCrSiN涂层硬度、膜/基结合强度以及摩擦磨损性能。系统分析沉积温度对AlCrSiN涂层的成分分布、微观结构演变、力学性能的影响,并研究沉积温度对AlCrSiN涂层摩擦磨损性能的影响规律及磨损机制。结果 随着沉积温度逐渐升高,涂层吸附原子的活性增强,涂层沉积速率出现先上升、再下降的趋势。随着沉积温度升高,涂层中的Cr₂N相逐渐替代CrN相,且hcp-AlN相沿(11■0)晶面择优生长。各沉积温度下,AlCrSiN涂层均与单晶硅片基体表面结合良好,且具有良好的致密性。沉积温度的升高,增强了原子的扩散能力,致使晶粒尺寸增大。随着沉积温度升高,涂层的硬度及弹性模量均呈上升趋势,而H/E、H³/E*²均先升高、后降低,涂层膜/基结合强度逐渐增大。当沉积温度为3...     

镁合金电火花沉积改性层性能及组织结构的研究

应用电火花沉积设备在AZ91D镁合金表面沉积纯铝涂层进行表面改性处理,研究了电火花沉积工艺参数以及前处理对沉积改性层性能和组织结构的影响;并结合扫描电镜、中性盐雾试验等研究手段对镁合金改性涂层的微观表面形貌、截面形貌、腐蚀情况以及显微硬度进行了分析和对比;同时,也对镁合金表面沉积纯铝涂层的沉积机理和沉积层改善基体耐腐蚀性、硬度进行分析与讨论。研究结果表明:电火花沉积工艺参数及预处理对AZ91D镁合金表面沉积纯铝涂层的组织结构、微观形貌特点有重要影响;电火花沉积工艺参数的降低以及沉积前对母材和电极的预热处理,涂层表面显微硬度较基材有了较大程度的提高;同时,强化层组织结构均匀致密、涂层厚度适中、涂层内部裂纹孔洞等缺陷明显降低,与镁合金基材相比,表现出较好的耐腐蚀性能。     

硬质合金刀具ZrC涂层的沉积

采用原位卤化反应直接形成的ZrCl4气体作为Zr源,在硬质合金刀具上沉积CVD-ZrC涂层。用SEM,XRD分析检测了合金刀具基底不同表面上沉积生长ZrC涂层的厚度均匀性、沉积速率、形貌组织、织构取向;通过理论计算与工艺实际的涂层沉积转化率对比,定量表征了该沉积体系工艺参数下ZrC涂层的沉积转化率。结果显示,CVD涂层炉内不同位置合金刀片表面沉积的ZrC涂层均匀;由于工艺温度限制,涂层沉积速率较低;ZrCl4转化为ZrC涂层的工艺实际转化率约11%,在理论最大转化率14%范围内;相同温度下随着沉积压力升高,涂层的沉积转化率缓慢降低到10%并趋于稳定;直接在合金基底沉积形成的ZrC涂层为细小的颗粒状形貌,而在合金基底TiN涂层表面上沉积生长的ZrC具有典型的片状组织形貌;对应的涂层生长织构取向从(311)到(111)转变。     

液相脉冲放电沉积涂层的温度场模拟及研究

通过有限元数值模拟的方法,选取合适的热源模型、热边界条件,建立了液体介质中在45钢表面进行脉冲放电沉积TiC陶瓷涂层的热传导模型。采用有限元分析软件ANSYS对液相脉冲电火花放电表面温度场进行数值模拟,研究了脉冲电流参数对温度场和涂层表面形貌的影响。结果表明:工具电极的最高温度远高于工件的最高温度;温度均在轴向上降低较快,而在径向上分布较均匀;最高温度随加工电流的增加呈缓慢下降趋势;随脉冲电流的增大,沉积到工件上的火山口状涂层颗粒明显增大。     

固态输送ZrCl4低压化学气相沉积制备ZrC涂层的特征

采用ZrCl4-CH4-H2-Ar反应体系、固态输送ZrCl4粉末低压化学气相沉积(CVD)制备ZrC涂层。研究温度对低压化学气相沉积ZrC涂层物相组成、晶体择优生长、涂层表面形貌、断面结构、涂层生长速度和沉积均匀性等方面的影响。结果表明:不同温度下沉积的涂层主要由ZrC和C相组成;随着温度的升高,ZrC晶粒(200)晶面择优生长增强,颗粒直径增大,表面致密性增加,沉积速率上升;涂层断面结构以柱状晶为主;随着离进料口距离的增加,涂层的沉积速率逐渐减小;1 500℃时,沉积系统的均匀性比1 450℃时的差。     

化学气相沉积钨铼合金工艺研究

以ReF6、WF6及H2为原料，用化学气相沉积法，成功地在铜基体表面沉积出钨铼合金。试验分析表明：合金成分均匀，且可由反应气体配比控制，随ReF6增加，合金中铼含量增加；沉积层组织和形貌随沉积温度升高或反应气体中ReF6的增加，由致密的柱状晶发展为杂乱的树枝晶；沉积层结构随ReF6的增加由单一固溶体向固溶体＋金属间化合物＋铼单质发展。     

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。     

冷喷涂TC4涂层临界沉积速度计算及制备涂层性能研究

目的研究冷喷涂TC4涂层的临界沉积速度及粒子温度对临界沉积速度的影响规律,并研究气体压强对沉积涂层性能的影响规律。方法理论研究上,采用有限元LS-DYNA软件中的Johnson-Cook塑性模型,选取3D164计算单元建立模型,研究粒子在不同温度和不同速度下碰撞基体后的形貌特征,确定粒子沉积临界速度。试验研究上,采用N_2作为冷喷涂驱动气体,在TC4合金上制备TC4涂层,然后采用SEM、Image J图像分析软件、硬度计等分析已沉积涂层的孔隙率和硬度等性能。结果 25、400、500、600℃温度下,计算表明10μm的TC4合金粒子在TC4基板上的临界沉积速度分别为730、465、392、361 m/s,即随粒子温度升高,粒子临界沉积速度降低,粒子沉积成涂层更容易。采用冷喷涂工艺在TC4基板上沉积TC4涂层,在N_2温度600℃、气体压力3 MPa的条件下,制备的TC4涂层厚度约1000μm,与TC4钛合金基体结合紧密,涂层孔隙率约为6.46%。结论气体温度升高,粒子临界沉积速度降低;气体压强变大,制备的涂层厚度就大且更加致密。     

沉积温度对高功率脉冲磁控溅射AlCrSiN涂层结构和性能的影响*

采用高功率脉冲磁控溅射(HiPIMS)技术在不同沉积温度下制备了Al-Cr-Si-N涂层。系统研究了沉积温度对涂层结构、成分、显微形貌、力学和摩擦学性能的影响。结果表明:随着沉积温度由100℃升至350℃,涂层内部开始由非晶向纳米晶转化,300℃时出现fcc-AlN相;涂层平整性和致密性逐步改善,膜/基结合强度逐渐提高,在300℃达到最大值77 N,但温度继续升高至350℃时,严重的轰击刻蚀作用使临界载荷骤降至25 N;涂层硬度逐渐增加,在350℃达到最大值19.4GPa;涂层内应力整体呈下降趋势,由–0.8 GPa逐渐降低至–0.4 GPa左右。     

Deposition and Characterization of HVOF Thermal Sprayed Functionally Graded Coatings Deposited onto a Lightweight Material

There is a significant interest in lightweight materials (like aluminum, magnesium, titanium, and so on) containing a wear resistance coating, in such industries as the automotive industry, to replace heavy components with lighter parts in order to decrease vehicle weight and increase fuel efficiency. Functionally graded coatings, in which the composition, microstructure, and/or properties vary gradually from the bond coat to the top coat, may be applied to lightweight materials, not only to decrease weight, but also to enhance components mechanical properties by ensuring gradual microstructural (changes) together with lower residual stress. In the current work, aluminum/tool-steel functionally graded coatings were deposited onto lightweight aluminum substrates. The graded coatings were then characterized in terms of residual stress and hardness. Results show that residual stress increased with an increase in deposition thickness and a decrease in number of layers. However, the hardness also increased with an increase in deposition thickness and decrease in number of layers. Therefore, an engineer must compromise between the hardness and stress values while designing a functionally graded coating-substrate system.     

Influence of Deposition Temperature on the Splat Bonding and Mechanical Properties of Plasma-Sprayed Tungsten Coatings

The mechanical properties of thermally sprayed metallic coatings are limited by the bonding between splats.In this study,tungsten coatings were deposited at different deposition temperatures by controlling the substrate temperature through shrouded plasma spraying.The dependence of the splat bonding and mechanical properties of W coatings on deposition temperature was investigated.The results showed that the apparent porosity of the coatings decreased from 3.2%to 0.3%with the increase of the deposition temperature.The Young’s modulus of W coating was significantly increased from 128 to 307 GPa as the deposition temperature increased from room temperature to 800°C.The microhardness of the coatings was less influenced by the deposition temperature.It was found that splat bonding across lamellae was formed when the deposition temperature was higher than 600°C compared to the obvious lamellae interface in the coatings deposited at temperatures lower than 600°C.The results evidently revealed that the mechanical properties of plasma-sprayed W coatings could be controlled through the splat bonding by altering deposition temperature.     

Deposition of alpha-WC/a-C nanocomposite thin films by hot-filament CVD

Nanostructured tungsten carbide coatings containing amorphous carbon (a-C) phases are interesting composite materials. The incorporation of the a-C phase simultaneously improves the thermal stabilization of the carbide phase and the coatings' friction coefficient. Such nanocomposite coatings are also electrically conducting with resistivity values comparable to the transition metals, which make them useful for a number of electrochemical and electronic applications. Many deposition techniques have been used for the synthesis of these coatings. However, most of them lead to the formation of complex crystalline structures consisting of more than one carbide phase and varying amorphous contents.The novelty of this work is the formation of WC coatings with controllable film thickness and a-C content, almost fully composed by α-WC phase. Tungsten carbide coatings were deposited on silicon substrates using a hot filament chemical vapor deposition (HFCVD) equipment with hydrogen and methane as the deposition gasses. Two types of nanocomposite coatings were obtained with significant variations of the carbide phase and a-C contents.The results point to the W vaporization time as the main parameter influencing the film thickness. We also conclude that the formation of α-WC phase is the combining result of W filaments vaporization in vacuum and the carbon incorporation at low substrate temperature. The small crystallite size of the carbide grains (5-6 nm) could also explain the rapid diffusion of C through the tungsten-containing layer. Preliminary results show that the amount of a-C incorporated in the film is not only dependent on the CH₄/H₂ ratio but also on the substrate temperature.     

Features of Coatings Obtained by Supersonic Laser Deposition

The three types of coatings that can be deposited by supersonic laser deposition, namely coatings built without the melting of the processed powder particles, coatings built from molten particles and coatings made from molten particles and with solid particles embedded in the coating, are discussed. For instance, with no melting of the powder material, a titanium alloy coating without transformation of the structure and with a uniform distribution of the chemical elements in the coating cross-section was obtained. Self-fluxing coatings (NiCrCBSiFe) with high hardness were achieved by melting the powder and mixing it with the substrate. The mixing of the coating metal with the substrate metal led to a significant increase in the concentration of the main alloying elements in the coating–substrate interface. X-ray diffraction analysis also showed that the mixing of the NiCrCBSiFe coating with a medium-carbon steel substrate led to the formation of new Fe_xNi phases, while their concentration decreased through coating thickness.     

Pulsed laser deposition of composite Mo–Se–Ni–C coatings using standard and shadow mask configuration

Thin film Mo–Se–Ni–C coatings for tribologycal applications were prepared by pulsed laser co-deposition from two targets — MoSe₂(Ni) and graphite. Two methods of deposition from the MoSe₂(Ni) target were used: deposition with unhindered expansion of the laser plume (standard PLD) and deposition of a plume scattered in collisions with Ar gas (pressure 2 Pa) in the shadow of a mask (shadow-masked PLD — SMPLD). Doping with carbon by PLD was used in all cases, and carbon content in the composite Mo–Se–Ni–C coatings was varied in the range 35–85.5 at.%. Pure MoSe_x(Ni) coatings were also prepared by PLD and SMPLD. Rutherford backscattering spectroscopy of helium ions, scanning electron and atomic force microscopy, electron probe microanalysis, transmission electron microscopy and micro-diffraction, micro-Raman spectroscopy, X-ray photoelectron spectroscopy and hardness evaluation were all used for comparative studies of the coatings obtained by PLD and SMPLD/PLD. In the PLD coatings, micron-sized particles were found, consisting of pure Ni or MoSe₂, as well as nanometre-sized particles of monocrystalline Mo. The nanoparticles were distributed on the surface and in an amorphous matrix in all PLD coatings. Within the amorphous matrix of the Mo–Se–Ni–C coatings, local ordering of atoms was detected, causing the formation of a mixture of amorphous carbon, Mo–C, and Mo–Se phases. Increasing the carbon content caused an increase in the content of sp³ bonds in the carbon phase, and an increase in the hardness of the coatings. SMPLD/PLD coatings had no micro- and nanoparticles, but these coatings were characterized by high selenium content and reduced density. Doping with carbon in the SMPLD/PLD configuration caused the formation of composite coatings containing Mo–Se and amorphous carbon phases as in the PLD coatings, but the hardness of the composite SMPLD/PLD coatings was significantly lower than even the hardness of the pure PLD MoSe_x(Ni) coatings.     

化学气相沉积温度对AZ31镁合金表面制备DLC薄膜微观结构及机械性能的影响

目的提高镁合金表面硬度及耐磨性,给出最佳性能薄膜的制备温度。方法采用化学气相沉积(PECVD)技术在AZ31镁合金表面制备了含氢DLC薄膜,研究了沉积温度对DLC薄膜厚度、表面形貌、硬度、杨氏模量、耐磨性能、膜基结合力以及sp^3键含量的影响,并对相应的影响机制进行了讨论。结果沉积温度对AZ31镁合金表面DLC膜的组织及性能有显著影响。温度较低时,碳粒子能量较低,无法注入薄膜亚表层,只能停留在表面以sp^2杂化方式生长。随着温度的升高,碳粒子能量增加,更多的sp^3杂化键形成。沉积温度为75℃时,薄膜中sp^3杂化键含量最多,此时薄膜最厚约为7.67μm,硬度最大可达5.95 GPa,杨氏模量值最高达到43.2 GPa,并且摩擦系数最低仅为0.03。随着温度进一步升高,碳粒子能量持续增加,轰击薄膜表面时会使碳-氢键断裂,造成氢的脱附,使薄膜中sp^3杂化键减少,从而降低了薄膜的硬度及耐磨性等机械性能。结论在本研究工作温度范围内,75℃为AZ31镁合金表面制备DLC薄膜的最佳温度。