气相沉积涂层技术与模具表面强化处理

介绍了在模具表面上气相沉积涂层的方法，分析了物理气相沉积和化学气相沉积的工艺特点及应用，指出模具表面气相沉积技术的发展方向。     

浅析硬质涂层的发展现状及未来趋势

经过数十年的发展,硬质涂层的发展已经上了一个新的台阶。从二十世纪七十年代化学气相沉积（CVD）技术制备TiN开始,经历了物理气相沉积技术的出现,TiAIN涂层的广泛应用,直至如今的A1TiN,CrAlN,TiAlSiN,金刚石等一系列新型涂层的诞生和应用．硬质涂层已经呈献百花齐放的态势。     

硬质合金刀具类金刚石涂层的摩擦磨损性能

以等离子体化学气相沉积技术在硬质合金刀具表面制备了类金刚石(DLC)涂层.研究了DLC涂层刀具和无涂层刀具的硬度,不同载荷、不同转速下两种刀具的摩擦磨损性能,以及在水润滑和油润滑条件下DLC涂层刀具的滑动摩擦行为.结果表明,DLC涂层刀具的平均硬度为2 099.9 HV,比无涂层刀具提高了48.3%;DLC涂层刀具的摩擦因数明显低于无涂层刀具,其磨损率随着载荷的增加而增大,随转速的增大而减小;油润滑比水润滑能更有效减缓摩擦作用.     

氮化硼纤维表面涂层的研究现状

综述了高性能连续氮化硼纤维表面涂层的研究现状,目前研究的氮化硼纤维表面涂层方法主要有物理气相沉积法(PVD)、化学气相沉积法(CVD)、溶胶凝胶法(Sol-gel)、溶液浸渍法等,其中溶液浸渍法是最为常用的方法,用此方法涂层过的氮化硼纤维,其防潮性能和力学性能都有了较大程度的提高。     

现代刀具涂层技术介绍

<正>一、刀具涂层刀具涂层是通过化学或物理的方法在刀具表面形成某种薄膜,使切削刀具获得优良的综合切削性能,从而满足高速切削加工的要求;自20世纪70年代初硬质涂层刀具问世以来,化学气相沉积(CVD)技术和物理气相沉积(PVD)技术相继得到发展,为刀具性能的提高开创了历史的新篇章。涂层刀具与未涂层刀具相比,具有显著的优越性:它可大幅度提高切削刀具寿命;有效地提高切削加工效率;提高加工精度并明显提高被加工工     

氧化铝陶瓷表面化学气相沉积钛涂层的制备及性能

利用卤化物还原原理,以Ti粉和I2粉为反应原料,通过化学气相沉积的方法在Al2O3陶瓷基体上制备了金属Ti涂层。考察了原料配比、加热温度及保温时间等工艺参数对涂层沉积的影响。通过X射线衍射仪分析了涂层的物相组成。利用扫描电子显微镜及能谱仪对涂层的微观组织形貌及成分进行了分析。采用座滴法考察铜与沉积了涂层的氧化铝陶瓷间的润湿性。研究结果表明,化学气相沉积法在氧化铝陶瓷表面制备Ti涂层的适宜工艺参数为:Ti与I2的质量比=1∶3,沉积温度为1 100℃,沉积时间为60min。所获得的Ti涂层纯度较高,具有明显的(110)晶面择优取向性,涂层与陶瓷结合良好。铜与涂层间的润湿角在1 113℃时为57°。     

固渗+EB-PVD法制备炭/炭复合材料防氧化复合涂层研究

制备出了SiC/SiC-Al2O3-Y2O3炭/炭复合材料防氧化复合涂层,该复合涂层的内层SiC基涂层采用料浆固渗法制备,SiC-Al2O3-Y2O3外层涂层采用大功率电子束物理气相沉积法。研究表明,电子束物理气相沉积法能达到较好的沉积效果,在制备过程中形成了柱状晶结构的涂层,使得涂层具有更高的应变容限,涂层非常均匀致密。用SEM、XPS和EDS等分析方法分析了涂层的防氧化机理。结果表明:在制备过程和氧化过程中,涂层内会发生复杂的物理和化学变化,生成硅酸盐氧化物,显示出电子束物理气相沉积法在制备炭/炭复合材料防氧化涂层方面独特的优势。     

低温化学气相沉积SiC涂层显微结构及晶体结构研究

在CH_3SiCl_3-H_2体系中,采用化学气相沉积法(CVD)在1000～1300℃制备了SiC涂层。研究了SiC涂层的沉积速率和温度之间的关系,发现低温化学气相沉积SiC为动力学控制过程,反应的表观活化能为85～156 kJ/mol。SiC涂层的外观颜色及涂层表面的显微结构随沉积温度变化而呈现规律的变化:当沉积温度<1150℃时,SiC涂层的外观颜色为银白色,涂层表面致密、光滑;当温度≥1150℃时,SiC涂层外观颜色逐渐变暗,涂层表面变得疏松、粗糙。利用XRD分析了不同沉积温度下SiC涂层的晶体结构,随着温度的升高,SiC涂层的结晶由不完整趋向于完整;当沉积温度≥1150℃,SiC涂层的XRD谱图中除了β-SiC外还出现了少量α-SiC。     

物理气相沉积硬质涂层的开发及工程应用

概述了物理气相沉积(PVD)技术的发展过程、特点及工程应用。介绍了香港城市大学先进涂层应用研究实验室(ACARL)近10年来在硬质涂层的开发与应用方面所做的主要工作,包括金刚石薄膜和纳米复合涂层在香港制造业的应用研究,超硬纳米复合涂层的完整性和可靠性研究,以及以脉冲磁控溅射为基础的新型大面积涂层技术的开发和工业化应用研究等。     

PVD／PECVD技术在模具工业上的应用

材料的摩擦，磨损，腐蚀，疲劳及其组合等问题的研究和卓有成效的解决途径成为当前表面工程领域研究的热点。本文主要介绍物理气相沉积和等离子增强化学气相沉积技术在模具工业上的应用。     

Cubic boron nitride films for industrial applications

The effects of kinetic energy, chemical nature of substrates and temperature on the synthesis of cBN films are explored to obtain cBN films with industrial quality. Carbon including amorphous carbon, nanocrystalline and polycrystalline diamond enables deposition of stable, thick and adherent cBN films with characteristic Raman signature. Although temperature has been designated as an unimportant parameter, the deposition at higher temperatures yields higher quality of cBN films. The higher temperature (800 °C) was also employed at cBN deposition on diamond coated tungsten carbide (WC) cutting inserts using plasma enhanced chemical vapor deposition (PECVD). The quality of cBN films grown by PECVD significantly overcomes that prepared by physical vapor deposition (PVD) which is affected in large extent by the lower kinetic energies of particles used in PECVD. The low kinetic energy of particles induces surface growth mechanism which differs from the growth models previously proposed.     

Physical vapor deposition technology for coated cutting tools: A review

Due to various difficult-to-machine materials and increasingly severe machining conditions, more and more attention has been paid to the physical vapor deposition (PVD) technology in recent decades to deposit hard coatings on cutting tools. Combined with the status of industrial application of PVD technology, this paper reviews the main PVD techniques for coated cutting tools from the perspective of the overall PVD coating equipment, including cathodic arc evaporation and magnetron sputtering as well as their hybrid techniques, and the plasma etching which is critical for coating adhesion strength is also involved. With regard to hard coating deposition on cutting tools, the basic principle, cathode configuration, magnetron and power supply are outlined. Issues related to target ionization ratio, coating deposition rate, coating properties and industrial application of numerous PVD techniques are also highlighted. On plasma etching, inert gas ion etching and metal ions etching are discussed. Finally, this paper summarizes and prospects the PVD technology used for coated cutting tools.     

化学气相沉积六方氮化硼涂层的制备及应用

六方氮化硼(h-BN)涂层是一种性能优异的功能陶瓷材料,介绍了化学气相沉积( CVD)六方氮化硼涂层的制备工艺,综述了h-BN涂层的优异性能和应用现状,并对其研究发展趋势进行了展望.认为先驱体性能存在缺陷、沉积机理复杂、工艺可控性差、生产成本高是目前CVD制备h-BN涂层存在的主要工艺问题,指出今后还需在新型先驱体的研发和使用、沉积机理的深入探究、工艺优化和放大等方面开展深入研究,以实现h-BN涂层的大规模工业化生产和应用.     

PCVD技术在刀具涂层中的应用

为了提高刀具的切削性能,比较有效的一种方法是采用各种涂层技术在刀具基体上涂覆上一层或者多层高硬度、高耐磨损性能的材料,可以显著地提高加工效率、提高加工精度、延长刀具使用寿命。CVD沉积温度高（约1 000℃）,PVD绕镀性差,在一定程度上限定了材料的适用范围,而等离子体化学气相沉积（PCVD）的出现,恰好克服了CVD和PVD的不足。概述了PCVD技术及其应用显著效果,希望对PCVD技术进行推广应用。     

Adhesion improvement of diamond coatings on cemented carbide with high cobalt content using PVD interlayer

At present, diamond coating is usually deposited on cemented carbide (WC-Co) tool with low Co content (Co ≤ 6 wt.%). It is more difficult to deposit diamond coating on WC-Co with high Co content because of the strong catalytic effect of Co. However, WC-Co tools with high Co content (Co ≥ 6 wt.%) are more widely used in difficult-to-cut materials machining because of their higher strength and better ductility. In this paper, the research was carried out on the adhesion performance of diamond coating on WC-Co (Co 10 wt.%). The deposition of diamond coating was conducted in hot filament chemical vapor deposition (HFCVD) system with the presence of the strong carbon-forming metallic interlayer (Nb, Cr or Ta), which was prepared using physical vapor deposition (PVD) on WC-Co substrate after chemical etching through a two-step process (Murakami solution and Caro's acid), which is a general way to treat the WC-Co substrate before growth of diamond coating. The results showed that the diamond films grown on the above treated WC-Co substrate have higher nucleation density, purity and adhesion strength than those on WC-Co substrates pretreated only using PVD interlayer or chemical etching. The PVD interlayer restrains the diffusion of Co as a result of high substrate temperature during the diamond film deposition, and consequently prevents the formation of the loosened layer induced by the removal of Co binder phase in the WC-Co substrate. The results also indicated that Nb interlayer leads to the most adhesion improvement of diamond films on the WC-Co inserts among the Nb, Ta and Cr interlayers.     

The introducing of fluorine into the deposition of BN: a successful method to obtain high-quality,thick cBN films with low residual stress

Cubic boron nitride films were synthesized on silicon substrates by DC-bias-assisted DC jet chemical vapor deposition in an Ar–N₂–BF₃–H₂ system. By this method, the deposition of cBN at high gas pressure of 50 torr became possible, and the conditions of cBN CVD approached to those of diamond CVD. cBN films with low residual stress (1–2 GPa) and with large crystal size of up to several hundred nanometers were obtained and clear Raman peaks of cBN appeared. Furthermore, the deposition rate was as high as 0.3 μm/min at the initial stage and over 20-μm-thick BN films were obtained for a 3-h deposition. These remarkable improvements are attributed to the preferential etching effect of fluorine to sp² bonds and the decrease of the bombarding energy of ions.     

高频热等离子体制备特种粉体研究进展

高频感应热等离子体具有能量密度大、温度高和冷却速率快等特点,是制备特种粉体的重要手段之一. 本工作介绍了过程所在高频热等离子体制备特种粉体方面的研究进展. 利用热等离子体的高温和快速冷却过程,粗颗粒经等离子体弧高温气化,通过控制冷却速率能得到纳米粉体,利用该方法制备了纳米球形硅、铁、钴和镍等粉体,纳米硅粉可用于锂离子电池负极材料. 具有固定熔点的不规则颗粒在等离子体弧中经熔融形成球形液滴,快速冷却能获得规则致密的球形颗粒,通过等离子体球化制备了高熔点的钨、钼、铌、铬等规则致密的球形粉体. 利用活性氢的瞬时强化还原反应,采用化学气相沉积能制备超细钨、钼、镍和铜等球形金属超细粉体. 活性氧有助于调控颗粒的氧化生长过程,采用金属等的氧化反应可获得多种特殊形貌的氧化物.     

Deposition of cubic boron nitride films on diamond-coated WC:Co inserts

Cubic boron nitride (cBN) thin films were deposited on diamond-coated tungsten carbide (WC) cutting inserts using electron cyclotron resonance (ECR) microwave plasma chemical vapor deposition (MPCVD). The effects of gas flow rate and substrate bias on the phase composition and structure of the BN films deposited on diamond surfaces were studied. It was revealed that both the cubic phase formation and the selective etching of hexagonal phase were controlled by modulating the hydrogen and boron trifluoride flow rate ratio. By the trial and error method the gas flow rate ratio and substrate bias voltage were optimized. Moreover the phase composition of the BN film was found to be affected by the thickness of diamond buffer layer and interrelated to the effective substrate bias. The hardness of the resulting cBN films reached the value of 70 GPa. In the synthesized coatings, the diamond beneath renders the best mechanical supporting capacity while the top cBN provides the superior chemical resistance and extreme hardness. The cBN/diamond bilayers deposited on WC inserts may serve as universal tool coatings for machining steels and other ferrous metals.     

Effects of an Electroplated Platinum Interlayer on the Morphology and Phases of Chemically-Vapor-Deposited Alumina on Single-Crystal, Nickel-Based Superalloy

The feasibility of preparing a thin layer of α-Al₂O₃ on the surface of a single-crystal, Ni-based superalloy was examined using a chloride-based chemical vapor deposition (CVD) process previously developed for cutting tool applications. A coating directly deposited by this method on the alloy surface consisted of ∼1 μm α-Al₂O₃ crystals in a matrix of amorphous Al₂O₃. When the alloy surface was predeposited with an electroplated Pt layer, the coating was mostly α-Al₂O₃, but with the presence of fine microcracks on the coating surface. In comparison to the results observed for pure Pt substrate, the role of the Pt interlayer was apparently to promote the rapid formation of κ-Al₂O₃ nuclei, which subsequently transformed to α-Al₂O₃ during the CVD growth process.