CVD温度对钼沉积层组织及性能的影响

介绍了化学气相沉积法(CVD)制备难熔金属钼膜层的原理和方法。以MoF_6和H_2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钼膜层。分析研究了沉积层的组织、结构和硬度。实验结果表明：沉积膜层显微组织随沉积温度变化而不同,沉积温度较低时,沉积层显微组织为细晶层状结构,沉积层硬度可达677×9.8 MPa：沉积温度较高时,沉积层显微组织为致密的柱状晶,硬度稍高于一般烧结钼的硬度。     

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。     

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℃.     

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。     

化学气相沉积法制备难熔金属的研究现状与前景

难熔金属材料以其熔点高、高温性能好和耐腐蚀性优异等特点被广泛应用于航空航天、化学化工和国防军工等领域。化学气相沉积法是目前获得高纯致密、尺寸精确的难熔金属制品的最佳手段。本文介绍了钨、钼、钽、铌和铼五种难熔金属元素的应用领域,综述了采用不同的化学气相沉积法制备难熔金属及其合金的工艺、制品性能和具体用途,总结了金属源先驱体类型对化学气相沉积工艺的影响,分析展望了化学气相沉积法在制备难熔金属上的应用前景。     

化学气相沉积钨显微组织缺陷的形成与控制

以WF6为前驱体,采用化学气相沉积法(CVD)在纯铜基体上沉积出钨涂层。利用光学显微镜(OM)和扫描电镜(SEM)分析研究钨制品组织缺陷的形成。结果表明:反应物浓度起伏对化学气相沉积钨的显微组织具有显著影响。当n(WF6):n(H2)≥1:3时,沉积物为柱状晶组织;当n(WF6):n(H2)1:3时,该沉积层晶粒明显细化,显微组织为细晶层状结构。另外,沉积过程中杂质形状也显著影响沉积层的显微组织。当基体表面存在一维杂质时,沉积制品表面产生明显的凸起,严重影响制品的表面质量和显微组织的均匀性;当沉积过程中存在零维杂质时,沉积层出现放射状的组织结构。     

双槽电沉积法制备Cu/Ag纳米多层膜

双槽电沉积法制备了不同调制波长的Cu/Ag金属多层膜(Cu膜和Ag膜等厚),用扫描电子显微镜观察了多层膜的层状结构,并研究了不同调制波长下多层膜的显微硬度变化.结果表明:双槽电沉积法制备的Cu/Ag多层膜层状结构明显.当调制波长大于100 nm时,显微硬度随调制波长减小而增加;当小于100 nm时,硬度随调制波长减小而...     

基板材料对激光熔化沉积制造Ti-48Al-2Cr-2Nb合金组织、织构、相和显微硬度的影响

本文研究了基体材料对激光熔化沉积Ti-48Al-2Cr-2Nb合金显微组织、织构、相组成和硬度的影响。随着沉积层数的增加,沉积层的显微组织由网篮状结构向等轴状结构转变,最终演变为层状结构。α2(Ti3Al)相逐渐减少,γ(TiAl)相逐渐增多。不同的TiAl合金层具有不同的显微硬度。随着沉积层数的增加,显微硬度降低。研究结果对于激光沉积制造TiAl合金制备具有可接受的组织、织构、相组成和显微硬度具有参考价值。     

CVD钨沉积层组织控制

以WF6和H2为反应气体,采用间断供应反应气体方法改变CVD钨沉积层显微组织形貌。研究了间断沉积工艺参数对沉积层显微组织及性能的影响,讨论了间断沉积层的表面应力状态及断口裂纹扩展情况。结果表明:采用间断化学气相沉积法钨层的显微组织随周期沉积时间的缩短,柱状晶晶粒长度尺寸变小,形态逐渐接近等轴晶;沉积层表面形貌呈圆球状,沉积层生长界面不再趋向于单一方向;钨层保持了连续CVD钨的高纯度、高密度特性。且采用间断供应反应气体沉积方法显著降低了钨制品表面的残余应力,使裂纹扩展方向发生改变,有效阻碍了裂纹的深入扩展。     

基板材料对激光熔化沉积制造Ti-48Al-2Cr-2Nb合金组织、织构、相和显微硬度的影响（英文）

研究了基体材料对激光熔化沉积Ti-48Al-2Cr-2Nb合金显微组织、织构、相组成和硬度的影响。随着沉积层数的增加,沉积层的显微组织由网篮状结构向等轴状结构转变,最终演变为层状结构。α_2(Ti_3Al)相逐渐减少,γ(TiAl)相逐渐增多。不同的TiAl合金层具有不同的显微硬度,随着沉积层数的增加,显微硬度降低。研究结果对于激光沉积制造TiAl合金制备具有可接受的组织、织构、相组成和显微硬度具有参考价值。     

The equiaxed-banded microstructural transition during low pressure plasma spraying

The microstructure of low pressure plasma spray deposited Al–12%Si has been investigated as a function of temperature during spray deposition, concentrating on deposit homogeneity, porosity, microstructure and microhardness. The deposit microstructure was determined by the temperature during spray deposition. Low temperatures promoted inhomogeneous banded microstructures, incorporating partially solidified and unmelted particles, with high levels of intersplat porosity, extended Si solubility in the α-Al matrix, amorphous and nano-sized Si precipitates and relatively high microhardness. High temperatures promoted homogeneous equiaxed microstructures, with low porosity levels, low Si solubility in the α-Al matrix, micro-sized Si precipitates, and relatively low microhardness. The measured critical transition temperature was in the range 190–345 °C, in reasonable agreement with Cantor et al.’s intermixing model of microstructure formation during spray deposition, which predicted a critical transition temperature of 328 °C. The corresponding critical intersplat time was estimated to be 1.4 × 10⁻⁴ s, indicating intermediate cooling conditions for splatting droplets arriving at the deposit surface.     

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.     

基于等离子熔覆快速成形零件的组织与性能

为了采用微束等离子弧粉末熔覆快速成形技术,在低碳钢基板上进行了铁基合金粉末Fe313的直接金属成形试验.通过光学金相显微镜和扫描电镜观察分析了成形金属零件显微组织和形貌,并利用维氏硬度计测试了熔覆层的显微硬度.结果表明,成形件中部典型组织表现为岛状的M-A组元,层与层结合处可看到明显的组织分界,先成形层受到后成形层的热影响,会引起晶粒细化,成形件硬度沿高度呈U形分布,中间熔覆层由于后道焊缝的回火作用而有所软化,导致硬度降低.     

TC4钛合金低压电子束熔丝沉积层组织与性能

对TC4钛合金进行了低压电子束熔丝沉积试验,探究了该方法的可行性,并分析了沉积层数对微观组织和性能的影响. 结果表明,在加速电压为10 kV的低压时也可完成TC4钛合金的多层熔丝沉积. 多层沉积之后得到的沉积件的平均显微硬度在260 HV左右,只有沉积件底部条带状纹理聚集处的显微硬度接近退火态TC4基材的288 HV. 条带状纹理产生于多层沉积的过程之中,β相晶粒受热循环影响而发生了β → α + α′ + β的转变,其中硬度较高的网篮状α′相与片状的α相组成了条带状纹理,该显微组织的特点是随着与基板距离的增加,网篮状组织逐渐融入片状组织. 沉积件的拉伸断裂形式为韧性断裂,最高抗拉强度为862 MPa,略低于国家标准,这是因为在多层沉积的沉积件中β柱状晶会变得巨大,同时还会出现等轴晶,晶粒的巨大化使得沉积件的抗拉性能出现了下降.     

变极性等离子弧铝合金熔覆层组织和性能

采用变极性等离子弧熔覆技术在2219铝合金试板表面制备了熔覆层,用金相显微镜、扫描电子显微镜和能谱仪对熔覆层进行了显微组织形貌观察和元素分析,用显微硬度计对熔覆层显微硬度进行了测试.结果表明:熔覆层底部组织为垂直于熔合线方向生长的柱状晶,中上部为较细小的等轴晶;熔覆层在凝固过程中析出Q强化相;熔覆层具有较均匀的显微硬度.     

Microhardness as a simple means of estimating relative wear resistance of carbide thermal spray coatings: Part 1. characterization of cemented carbide coatings

A selection of WC-Co and Cr₃C₂-25%NiCr coatings deposited by plasma spraying and high velocity oxygen fuel (HVOF) were tested. The microstructures of the coatings were characterized, and their mechanical properties were assessed using Knoop microindentation procedures. The coatings were also subjected to various wear tests. All of the coatings were at least 200 μm thick and were deposited onto stainless steel substrates. The wear tests simulated abrasion, cavitation wear, sliding wear, and particle erosion wear. In this first part of a two-part contribution, the microstructures of the coatings are characterized and a discussion on the evaluation of mechanical properties from the microindentation response is presented. The nature of microhardness testing as applied to thermal spray coatings is evaluated as a means of assessing resistance to plastic flow, elasticity, and brittleness. In Part 2, the results of the various wear simulations are reported, and the utility of microhardness as an indicator of wear resistance is examined.     

Micromechanical properties of Co-W alloys electrodeposited under pulse conditions

Results of the investigation of pulse current frequency influence (rectangular unipolar pulses, i _m = 3 A/dm², relative pulse duration 3, frequency 0.67–333 Hz, Q = 3600 C/dm²) on the properties of Co-W alloys at electrochemical deposition—deposition rate, current efficiency, structure of obtained coatings, and their microhardness (microindentation and sclerometric ones)—are presented. The correlation between the microhardness determined by quasi-static indentation and the “organic” phase content in the alloy is shown (the microhardness decreases as the total content of carbon and oxygen in the deposited layer increases). Sclerometric tests have shown that microhardness increases with an increasing tungsten concentration in the deposited layer.     

Effect of substrate temperature on the structure of Ag-Cd condensates

Ag-6.0 wt.% Cd condensates of 100 μm thickness were produced by an electron beam physical vapor deposition technique on substrates, which were at temperatures of 150-650 °C. It is shown that substrate temperature influences not only the microstructure of the condensates, but also their grain substructure; so, twinning of grains is observed in the condensates deposited at substrate temperatures below the critical temperature of 300 °C. The thickness of the twin domains tends to decrease down to nano-scale with a decrease in the substrate temperature. The microhardness of the condensates with nano-twinned grains is several times higher as compared to that of the condensates showing no twins in the grains.     

钛合金表面反应电火花沉积TiN/Ti复合涂层

利用自制的电火花沉积充气密闭式保护装置和DZ-1400型电火花沉积/堆焊机,以工业纯钛TA2为电极,以工业纯氮为保护气和反应气,在TC4钛合金表面上反应电火花沉积制备了TiN/Ti复合涂层.利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、X射线光电子仪(XPS)分析了涂层的组织、物相和元素组成,利用显微硬度计测定了涂层的显微硬度,利用自制磨损试验装置对比涂层与淬火W18Cr4V高速钢的磨损性能.结果表明,涂层与基体形成良好的冶金结合,涂层主要由钛和反应合成的TiN组成,涂层的平均显微硬度可达1 388 HV0.1,是基体硬度的6倍以上,涂层具有较好的耐磨性.

Abstract：

TiN/Ti composite coating was deposited on TC4 titanium alloy substrate with the self-made special gas-filled-closed electric-spark deposition device and electric-spark deposition machine modeled DZ-1400, the industry pure titanium (TA2) was used as electrode and the industry pure nitrogen gas as shielding and reacting atmosphere. The microstructures, interfacial behavior, phase and element in the coatings were investigated by scanning electronic microscope, X-ray diffraction and X-ray photo spectrum. The microhardness of coatings was tested and its wear-resistance property was tested by the self-made abrasion machine and compared with Wi8Cr4V rapid steel treated by quenching. The results show that an excellent bonding between the coating and substrate is ensured by the strong metallurgical interface. The coatings are mainly composed of Ti and synthesized TiN. The highest microhardness of coating reaches to 1 388 HV0. 1, which is six times higher than that of the substrates. Wear resistance of the coatings is excellent.     

Improved coatings by isodynamic compression

Selected platelet-powder mixtures that were fabricated from spin-cast ribbon were deposited using arc plasma spraying at various velocities (from subsonic to supersonic) to form rapidly solidified coatings with mechanical-type bonding on a low alloy steel substrate. After deposition at ambient temperatures these sprayed coatings were then subjected to transformation treatments at two elevated temperatures using hot isodynamic compression (HIC) techniques. Efforts aimed at using transformation to achieve greater densities, higher strength and metallurgically bonded coatings are described for an Ni- Mo-Fe-B alloy. HIC and hot isostatic pressing approaches were compared statistically and the significant experimental variables were characterized using Vickers microhardness or electron metallography (scanning electron metallography, electron diffraction spectroscopy and energy-dispersive X-ray microanalysis).