电弧离子镀氮化铬涂层的高温氧化

利用电弧离子镀设备在1Cr11Ni2W2MoV不锈钢基体上沉积了CrN涂层,对涂层的抗氧化性能进行了研究.结果表明,CrN氧化生成Cr2O3,氧化反应激活能小于Cr和Cr2N的氧化反应激活能,具有低的氧化速率常数,抗氧化性能良好.氧化过程中发生CrN向Cr2N的相转变,涂层中大的压应力的存在对这一转变起了关键作用.     

Ti基与Cr基氮化物涂层的抗氧化性能

选用TiN,TiAlN,CrN和CrAlN 4种涂层材料,使用电阻炉对试样加热并保温,进行抗氧化性能实验,利用SEM、EDS和XRD获得了氧化结果。结果表明:Ti基涂层的氧化机制以O原子向涂层内部扩散为主;Cr基涂层的抗氧化机制为N原子和Cr离子向涂层表面的扩散所形成的微孔诱发的氧化;Cr基涂层比Ti基涂层具有较好的抗氧化性;Al的加入使得TiAlN与CrAlN涂层的氧化性能和高温后硬度提高,特别是CrAlN氧化后生成的致密Cr2O3和Al2O3混合氧化物使其抗氧化性能达到最优;氧化及涂层与基体的热涨失配使得几类涂层最终开裂失效;四种涂层的抗氧化能力为CrAlN>TiAlN>CrN>TiN。     

CrN和CrAlN涂层热稳定性、力学和摩擦学性能研究

目的 针对现有刀具用硬质CrN及CrAlN涂层的热稳定性研究尚属空白,以及对其涂层摩擦学性能的影响尚不清楚等问题,开展CrN和CrAlN涂层的热稳定性、氧化行为、力学性能及摩擦磨损性能研究。方法 采用中频反应磁控溅射技术制备CrN和CrAlN涂层,利用真空热脱附系统、场发射扫描电镜、原子力显微镜、能谱仪、X射线衍射、拉曼光谱仪、纳米压痕仪和摩擦磨损试验机等探究2种涂层的结构、热稳定性、力学性能和摩擦学性能。结果 在真空温度为646 ℃左右时,CrN涂层开始发生N分解和释放,在885 ℃左右时N的释放速率达到峰值。CrAlN涂层在真空温度为722 ℃左右时才开始发生N分解和释放,而在1 000 ℃下N的释放速率并未达到峰值。在大气温度600 ℃下,CrN涂层开始发生氧化,并生成Cr2O3相,且Cr2O3层的厚度随着温度的升高而增加,在900 ℃时涂层完全氧化。CrAlN涂层在900 ℃时才开始发生氧化,生成更为致密的Cr2O3和Al2O3混合氧化层,阻止涂层进一步氧化。在大气高温条件下,CrAlN涂层均具有比CrN涂层更高的硬度和弹性模量。随着温度的升高,2种涂层的表面粗糙度逐渐增加,摩擦因数逐渐降低,CrAlN涂层在600、800 ℃下的表面粗糙度和磨损率均低于CrN涂层。结论 在真空下,CrAlN涂层中键能较高的Al-N共价键改善了涂层的热稳定性,提高了CrAlN涂层中N的分解温度。在大气中,CrAlN涂层具有比CrN涂层更高的抗氧化性、硬度和弹性模量,CrAlN涂层在高温氧化过程中生成了连续且致密的Cr2O3和Al2O3混合氧化层,能够减缓O原子向涂层内部的扩散。CrAlN涂层具有比CrN涂层更优异的耐磨性,更适合作为高温工况下服役的刀具和模具等易磨损材料的防护涂层。     

Si、Cr的加入对TiAlN涂层抗氧化性能的影响

比较了阴极电弧蒸发工艺制备的Ti0.45Al0.55N、Ti0.35Al0.55Si0.1N和Ti0.3Al0.55Cr0.15N涂层在850℃和900℃的抗氧化性能。通过X射线衍射仪(XRD)、高分辨率扫描电镜(HRSEM)和能谱仪(EDS),研究Si、Cr对Ti0.45Al0.55N涂层抗氧化性能的影响。结果表明:Si和Cr的加入均能有效提高Ti0.45Al0.55N涂层的抗氧化性能,细化涂层晶粒,促进Al向涂层表面扩散形成致密的Al2O3氧化层,抑制锐钛矿型TiO2向金红石型TiO2转变,提高TiAlSiN涂层和TiAlCrN涂层的抗氧化性能。另外,TiAlCrN涂层中Cr2O3的形成进一步提高了其抗氧化性能。     

反应磁控溅射制备CrN涂层的热稳定性

目的 研究了真空、大气2种环境下CrN涂层的热稳定性与氧化行为。方法 采用反应磁控溅射技术在(100)取向的P型单晶硅基底上制备了CrN涂层。利用真空热脱附谱(TDS)、场发射扫描电子显微镜(FESEM)、拉曼光谱(Raman)、X射线衍射(XRD)和扫描电子显微镜(SEM)以及加装的能谱仪(EDS)等表征方法,研究了在不同温度下涂层的热稳定性与氧化行为。结果 在真空退火时,TDS结果表明CrN涂层中的N在664 ℃左右开始释放,在温度达到1 000 ℃时释放结束。而在温度高于900 ℃时释放速率和释放量开始迅速上升,在温度达到930 ℃时达到峰值。在加热过程中,涂层中的CrN相部分转变为Cr2N相,在温度达到1 000 ℃时,完全转变为CrSi2相。在大气环境中,当温度达到700 ℃时,涂层开始被氧化,涂层表面生成了一层约136 nm厚的致密氧化层,同时在氧化层下方生成了一层CrOxN1?x的过渡层,并且涂层也出现了Cr2O3的拉曼峰。当温度达到800 ℃时,Cr2O3氧化物拉曼峰和衍射峰的数量和强度显著增加,说明涂层表面生成的氧化物的结构由简单变为复杂,并且结晶性增强。此外,氧化物颗粒逐渐长大,氧化层厚度增加,在温度达到850 ℃时,氧化层厚度达到429 nm。当温度高于700 ℃时,CrN涂层沿着厚度方向的元素扩散行为是O元素的向内扩散和N、Cr元素的向外扩散,并且释放的N在氧化层下方富集,并没有释放出去。结论 CrN涂层在真空中的热稳定性在900 ℃左右,在大气中的热稳定性在700 ℃左右。在大气中致密的Cr2O3氧化层的形成对O元素的向内扩散和N、Cr元素的向外扩散具有很好的阻挡作用。氧化层的这种阻挡作用对涂层的内部起到保护作用,延缓了涂层进一步的氧化和分解,这是CrN涂层热稳定性较好的原因。     

磁控溅射Cr/CrN和Cr/CrN/CrAlN涂层的抗高温氧化性能

为了提高航空紧固件涂层的高温工况防护能力,采用磁控溅射技术在钛合金表面分别制备 Cr/ CrN 交替涂层和 Cr/ CrN / CrAlN 涂层,研究氧化时间和氧化温度对涂层高温氧化性能影响。 利用 SEM、EDS 和 XRD 进行微观形貌和物相成分分析,采用热重法分析氧化增重量( w) 和氧化速率常数( k) ,使用显微硬度计测试涂层高温氧化后硬度。 结果表明:随着氧化时间和氧化温度的增加,涂层硬度均降低,但 Cr/ CrN / CrAlN 涂层下降趋势更缓; 两种涂层的 w 和 k 均上升,其中 Cr/ CrN / CrAlN 涂层 w 和 k 增幅均低于 Cr/ CrN 交替涂层,950 ℃ 氧化 96 h 后 Cr/ CrN / CrAlN 涂层和 Cr/ CrN 交替涂层的 w 值分别为 40 mg / cm ² 和 135. 7 mg / cm ² ,其对应的 k 分别为 0. 1996 和 0. 4092,说明 Cr/ CrN / CrAlN 涂层抗高温氧化性更好。 Cr/ CrN / CrAlN 涂层活化能 E_a 值比 Cr/ CrN 交替涂层高 48. 5%,Cr/ CrN / CrAlN 涂层在高温下产生 Cr₂O₃ 和 Al ₂O₃ 的混合氧化物,结构更致密,Cr/ CrN / CrAlN 涂层抗高温氧化性能高于 Cr/ CrN 交替涂层。     

反应磁控溅射沉积工艺对Cr-N涂层微观结构的影响

研究在不同工艺条件下用直流反应磁控溅射技术在T10衬底上制备Cr-N涂层,并采用光电子能谱仪和XRD依次分析Cr-N涂层的表面结构和工艺参数对Cr-N涂层成分及相组成的影响。结果表明,Cr-N涂层在存放一段时间后表面产生复杂的Cr2O3相以及Cr（O2 N）x相;常温下随着N2含量的增加,涂层相结构逐渐由Cr转变为化学比的CrN相。当N2含量为33-3％时,Cr-N涂层的相成分主要为Cr2N＋CrN。并发现衬底偏压直接影响Cr-N系涂层的晶态及取向特征,当偏压增加到-130V时,Cr-N涂层中β-Cr2N相结构逐渐转变为（110）和（300）取向结构。     

Cr-Al-N涂层的热稳定性及力学性能研究

借助XRD、SEM、EDX、纳米压痕、氧化实验和切削实验研究了采用阴极弧蒸发技术制备的Cr-Al-N涂层的热稳定性、高温抗氧化性能和力学性能。研究表明:Cr0.32Al0.68N涂层为面心立方结构;Cr0.32Al0.68N在高温时会发生向其稳定相h-AlN和c-Cr发生转变,其中Cr的生成由中间生成物Cr2N过渡完成;Cr0.32Al0.68N涂层由于高的热稳定性和高温抗氧化性能,其切削性能优于普通的Ti-Al-N涂层。     

钼添加对CrN涂层抗氧化性能的影响（英文）

研究钼添加对CrN涂层微观结构和抗氧化性能的影响,采用反应磁控溅射法在硅片和高速钢片上制备不同Mo含量的Cr-Mo-N涂层,并在500～800℃的高温空气中退火1 h,用X射线衍射(XRD)、拉曼光谱和扫描电子显微镜(SEM)对涂层退火前后的微观形貌进行表征。沉积的Cr N和Cr-Mo-N涂层均表现出基于Cr N晶格的B1面心立方相(fcc)。Mo离子取代CrN晶格中的Cr离子,形成CrMo-N固溶体。在600℃时,XRD和拉曼光谱表明,Mo含量较高的Cr-Mo-N涂层中形成MoO_3相,表面较粗糙,含氧量较高。在700℃时,CrN涂层由于内应力的作用,其横截面形貌为疏松的柱状晶,并有一定的多孔区,而Cr-Mo-N涂层则为致密的柱状晶结构。低Mo含量(17at%)的Cr-Mo-N涂层比Cr N涂层具有更好的抗氧化性。     

多弧离子镀制备的大厚度Cr/Cr_2N/CrN多层涂层的结构和力学性能（英文）

采用多弧离子镀制备一种厚度为24.4μm的Cr/Cr2N/CrN多层结构涂层。采用场发射扫描电子显微镜(FESEM)、X射线光电子能谱(XPS)、能量散射谱(EDS)、X射线衍射(XRD)和透射电镜(TEM)对涂层进行表征,并用纳米压痕和划痕仪测试其硬度和结合力。用UMT-3MT往复式摩擦磨损试验机对涂层在大气和海水环境中的摩擦性能进行测试。结果表明,该涂层由3种相结构组成,分别是Cr相、Cr2N相和CrN相。相对于单层CrN涂层,多层涂层的结合力明显提高,该涂层的硬度为(21±2)GPa。多层结构涂层在人工海水中的耐蚀性能显著优于单层CrN涂层的耐蚀性能,且在大气和海水中多层结构涂层的摩擦因数均低于单层CrN涂层的摩擦因数。     

Korrosionsverhalten von Hybridschichtsystemen

Corrosion behaviour of hybrid coating systems Potentiodynamic methods were used to investigate the corrosion protection value of various hybrid coating systems. Combinations of galvanic chromium and electroless nickel interlayers with titanium nitride and chromium nitride coatings produced by sputterion-plating method were tested. Anodic polarization curves show that corrosion resistance is strongly connected with the microdefects present in the coatings. The coating system consisting of chromium nitride with electroless nickel as an interlayer exhibits excellent corrosion resistance properties in 1N H₂SO₄ solution. The reason for this behaviour is presented and discussed in detail.     

Oxidation and Ablation Resistance of Low Pressure Plasma-Sprayed ZrB2-Si Composite Coating

In the present work, ZrB₂-based coating containing Si additive was prepared by low pressure plasma spray process. The chemical composition and microstructure of the ZrB₂-Si coating were characterized by XRD, EDS and SEM. The oxidation behavior of the coating was investigated in ambient air for different duration time. The ablation-resistant property of the coating was carried out using a plasma flame. The results obtained indicate that the ZrB₂-Si composite coating exhibited compact lamellar microstructure with a porosity less than 5%. The silicon phase was uniformly distributed in the ZrB₂ matrix. The composite coating presented excellent oxidation-resistance at high temperature of 1500 °C, which resulted from the formed continuous and dense glassy silicon oxide film on its surface. The ablation resistance of the ZrB₂-Si coating has been proved to be excellent, which could withstand the plasma flame (above 2000 °C, atmosphere) for 10 min.     

Microstructure of electroplated hard chromium coatings after plasma nitrocarburizing

Plasma nitrocarburizing was carried out on the hard chromium coating deposited on SM45C mild carbon steel substrate by electroplating. After plasma nitrocarburizing at 720 °C for 20 h, a 6–7-μm-thick nitride layer consisting of CrN and Cr₂N was formed on the surface of Cr coating with the microhardness of about 950–1100 HV0.1. Due to the effect of annealing caused by plasma nitrocarburizing process at higher temperature and the Cr being a strong carbide-forming element, the carbon in steel substrate diffused outward into the Cr coating and reacted with Cr forming Cr carbide interface layer between the Cr electroplating and substrate. The nitrogen going into the microcracks and the volume increase accompanied by Cr nitride and carbide formation would cause the microcracks inherent to hard chromium plating disappear and improve its corrosion resistance. The microstructures of nitride and carbide layers were studied using X-ray diffraction and cross-sectional transmission electron microscopy.     

Ni-P-纳米TiO_2化学复合镀层

研究了化学复合镀Ni–P–纳米TiO2粒子涂层的工艺过程和涂层性能。结果显示超声分散再加上表面活性剂可以使TiO2粒子得到充分分散。所获得的Ni–P–纳米TiO2粒子复合涂层和Ni–P合金涂层相比具有更高的硬度和高温抗氧化性能。镀层热处理后,Ni–P–纳米TiO2粒子复合涂层的硬化峰值出现在500 左右。化学镀Ni–P合金涂层的硬化峰值在400 左右。     

A technique for fabrication of coated TiCN-based cermets with functionally graded structure

A technique for fabrication of coated TiCN–Ni–Mo cermets with functionally graded microstructure and composition has been developed. A multilayer coating and the substrate near-surface zone with graded microstructure form as a result of interaction between the cermets and chromium vapour in vacuum. The coating consists of an upper layer of chromium carbide of about 10 μm in thickness and a thin interlayer of less than 1 μm composed of a Ni–Cr alloy between the carbide layer and the substrate. The wide near-surface zone of over 100 μm in thickness with graded microstructure and composition forming under the coatings has an increased Cr content in the Ni-based binder. This zone is characterised by enhanced corrosion- and oxidation-resistance.     

等离子喷涂 NiCoCrAlY / Al2 O3 高温固体润滑耐磨涂层的抗氧化性能研究

目的研究等离子喷涂NiCoCrAlY/Al2O3高温固体润滑耐磨涂层在850℃时的高温抗氧化性能和抗氧化机理。方法采用喷雾造粒、化工冶金包覆技术制备NiCoCrAlY/Al2O3复合粉体,并采用等离子喷涂技术在45#钢表面制备NiCoCrAlY/Al2O3复合涂层。采用SEM和XRD研究粉体和涂层的显微结构和物相组成,并采用马弗炉研究复合涂层在850℃的恒温氧化动力学曲线,通过研究氧化96 h以后涂层表面的组织形貌,探讨NiCoCrAlY/Al2O3复合涂层的抗氧化机理。结果 NiCoCrAlY合金层均匀致密地包覆在Al2O3颗粒的表面,包覆层厚度约为3~5μm。复合粉体的主要组成为Al2O3相和NiCoCrAlY合金相,没有其他杂质相的存在。等离子喷涂NiCoCrAlY/Al2O3复合涂层氧化动力学曲线分为大斜率直线、抛物线和系数几乎为0的抛物线等3个阶段。氧化96 h以后,涂层的氧化质量增量为4.9 mg/cm2左右,表面形成了一层连续的氧化物保护膜,经EDX分析,氧化膜层主要由Al,O,Cr和Ni组成。结论等离子喷涂NiCoCrAlY/Al2O3复合涂层具有良好的高温抗氧化性能,涂层中Ni,Cr,Al的氧化以及硬质相Al2O3的加入是涂层抗氧化的主要原因。     

Microstructure of chromium nitride layer on stainless steel for polymer electrolyte membrane fuel cell separator

The microstructure of the chromium nitride layer formed on 316L Stainless Steel (SS) by electroplating Cr and subsequent thermal nitriding was investigated by electron microscopy. Thermal nitriding was carried out at a nitrogen partial pressure of 100 torr at 1100 °C for 2 h. The X-ray Diffraction (XRD) patterns showed that the structure of electroplated chromium was not crystalline and that the nitrided layer was composed of only hexagonal Cr₂N phase nitride. The nitride layer showed uniform and columnar-shaped grains of chromium nitride and contained many micro-pores that may have formed due to the volume difference between the amorphous chromium and the crystalline chromium nitride. Chromium oxide was also observed in the nitride layer. It was discovered that the number of micro-pores and oxide particles needs to be decreased in order to improve the interfacial contact resistance.     

Stainless Steel Bipolar Plates Deposited with Multilayer Films for PEMFC Applications

A chromium nitride (CrN, Cr₂N)/chromium (Cr)/indium-tin-oxide (ITO) system and a gold (Au)/titanium (Ti) system were separately deposited using a sputtering method and an E-beam method, respectively, onto stainless steel 316 and 304 plates. The XRD patterns of the deposited stainless steel plates showed the crystalline phase of typical indium-tin oxide and of metallic phases, such as chromium, gold, and the metal substrate, as well as those of external chromium nitride films. The nitride films were composed of two metal nitride phases that consisted of CrN and Cr₂N compounds. The surface morphologies of the modified stainless steel bipolar plates were observed using atomic force microscopy and FE-SEM. The chromium nitride (CrN, Cr₂N)/chromium (Cr)/indium-tin-oxide (ITO) multilayer that was formed on the stainless steel plates had a surface microstructural morphology that consisted of fine columnar grains 10 nm in diameter and 60 nm in length. The external gold films that were formed on the stainless steel plates had a grain microstructure approximately 100 nm in diameter. The grain size of the external surface of the stainless steel plates with the gold (Au)/titanium (Ti) system increased with increasing gold film thickness. The electrical resistances and water contact angles of the stainless steel bipolar plates that were covered with the multilayer films were examined as a function of the thickness of the ITO film or of the external gold film. In the corrosion test, ICP-MS results indicated that the gold (Au)/titanium (Ti) films showed relatively excellent chemical stability after exposure to H₂SO₄ solution with pH 3 at 80 °C.     

Corrosion protection of sintered NdFeB magnets by CAPVD Ti2N coating

Sintered NdFeB magnets have poor corrosion resistance and are readily susceptible to corrosion under different environmental conditions. Cathodic arc physical vapour deposited (CAPVD) titanium nitride coating for sintered NdFeB permanent magnets has been investigated in this paper. Tafel extrapolation was employed to study the corrosion behaviour in 3.5% NaCl solution at ambient temperature. The adhesive strength of the coating was estimated with the help of the scratch test. The surface chemistry and coating morphologies were studied with scanning electron microscope (SEM). X-Ray diffraction (XRD) was used for qualitative phase analyses of coatings and substrate. The properties of CAPVD titanium nitride coating were compared with electrodeposited multilayer nickel–copper–nickel coating. It was figured out that the CAPVD titanium nitride coating had better adhesion strength and shifted the free corrosion potential (FCP) of the system towards positive potential, providing protection to the NdFeB substrate. However, the corrosion rate of CAPVD titanium nitride coating was more than the electrodeposited multilayer nickel–copper–nickel coating. The magnetic properties remained comparable.     

TiN-TiB2 composite coatings reactively produced by electrothermally exploded powder spray

Composite coatings composed of titanium nitride, TiN, and diboride, TiB₂, were reactively produced by the electrothermally exploded powder spray technique, in which feedstock powder was prepared from titanium and boron nitride particles. The microstructure of the coating was composed of titanium-ceramic particles the size of which were on the order of several nanometers to a few hundred nanometers. Such reactive thermal spraying brought base-metal saturation into a coating layer at the early stages of coating formation. The ceramic composite spray using feedstock of TiN and TiB₂ particles preferentially brought a new phase of cubic titanium boronitride together with TiN and TiB₂ into a coating. On comparing such a coating to one produced by the conventional method, the reactive thermal spray coating was richer in TiN and TiB₂ due to the excess nitrogen in the feedstock.