改善电弧离子镀涂层大颗粒的试验研究

电弧离子镀涂层的大颗粒使涂层表面粗糙度、孔隙率增加,直接影响涂层的力学性能和表面质量,着重介绍了在涂层中引入稀土元素和采用新型底层系统电弧靶对减少电弧离子镀大颗粒和提高涂层致密度的情况。     

(Ti,Al)N梯度薄膜中的残余应力分析

采用电弧离子镀膜技术在1Cr11Ni2W2MoV不锈钢表面沉积了Ti1-xAlxN/Ti梯度薄膜.在700℃和800℃进行了高温氧化实验.对梯度薄膜常温和高温下的残余应力分布及薄膜和基体的结合状态进行了研究.研究结果表明,由于膜层是成分分别为Ti、TiN、Ti0.75 Al0.25 N、Ti0.6 Al0.4N和Ti0.5 Al0.5N梯度层组成,实现了成分和结构的梯度变化,各单层之间以及薄膜和基体之间的热膨胀系数不匹配程度降低,晶格错配度下降,薄膜中的残余应力降低;高温下,本征应力松弛,热应力转变为拉应力,薄膜和基体仍能维持较好的结合状态.     

分离靶电弧离子镀制备TiN/TiAlN多层薄膜的微观结构和力学性能(英文)

采用分离靶电弧离子镀制备TiN/TiAlN多层薄膜。为了减少大颗粒的不利影响,利用直线型磁过滤方法来减少低熔点铝靶产生的大颗粒。结果表明,没有过滤的钛靶和磁过滤的铝靶等离子体到达基体的输出量在相同的数量级,同时,采用该方法制备的薄膜中的大颗粒数目是文献中报道的合金靶制备的薄膜大颗粒数目的1/10～1/3。Al元素的添加引起薄膜在(200)晶面的峰值降低,而在(111)和(220)晶面的峰值增强。TiN/TiAlN多层薄膜的最大硬度为HV2495,薄膜的硬度增强符合混合法则,结合力达75 N。     

电弧离子镀沉积NiCrAlY涂层的阻尼性能

本文采用电弧离子镀沉积NiCrAlY涂层,探讨NiCrAlY涂层作为阻尼涂层的可行性并研究涂层的阻尼测试方法和阻尼特性。本文采用X射线衍射和扫描电镜等手段分别对涂层的物相结构、表面形貌以及化学成分进行了测试表征。而涂层阻尼的测试则采用动态机械分析仪和正弦扫频的方法进行,实验结果表明NiCrAlY涂层能明显提高样品的阻尼性能。     

电弧离子镀方法制备的Ti/TiN多层膜的结构与耐腐蚀性能

采用电弧离子镀技术,通过周期性变换环境气氛,在7075Al合金上制备了Ti/TiN多层膜,并研究调制周期对多层膜的结构组成和腐蚀性能的影响。结果表明:多层膜与铝合金衬底界面结合较好,基本没有孔洞等缺陷。多层膜具有明显的层状特征,层间界面清晰。多层膜中TiN与单层中TiN薄膜有着相同的晶体结构,并存在(111)择优取向,每个调制周期内的TiN层都呈柱状生长。随着调制周期变小,多层膜阳极极化曲线的腐蚀电位增加,交流阻抗谱的阻抗值增大,容抗弧的半径也增大,即膜层的耐腐蚀性增加。多层膜调制周期的减小使得薄膜中含有的层界面增多,而贯穿至衬底表面的针孔等缺陷的数量将减少,这样,腐蚀性介质经过针孔等缺陷与衬底接触的机会变少,这将使薄膜的抗腐蚀能力得到改善。     

Effect of partial pressure of reactive gas on chromium nitride and chromium oxide deposited by arc ion plating

The effects of reactive gas partial pressure on droplet formation, deposition rate and change of preferred orientation of CrN and Cr2O3 coatings were studied. For CrN coatings, as nitrogen partial pressure increases, the number and size of droplets increases, the deposition rate initially increases obviously and then slowly, and the preferred orientation of CrN changes from high-index plane to low-index one. For Cr2O3 coatings, with the increase of oxygen partial pressure, the number and size of droplets decreases, the deposition rate decreases and the （300） becomes the preferred orientation. These differences are ascribed to the formation of CrN （with a lower melting point） and Cr2O3 （with a higher melting point） on the surface of Cr target during the deposition of CrN and Cr2O3. Complete coatings CrN or Cr2O3 film can be formed when reactive gas partial pressure gets up to 0. l Pa. The optimized N2 partial pressure for CrN deposition is about 0.1-0.2 Pa in order to suppress the formation of droplets and the suitable 02 partial pressure for Cr2O3 deposition is approximately 0.1 Pa for the attempt to prevent the peel of the coating.     

Effects of nitrogen pressure and pulse bias voltage on the properties of Cr-N coatings deposited by arc ion plating

Cr-N coatings were deposited on 1Cr18Ni9Ti stainless steel in the pure N₂ atmosphere by arc ion plating (AIP). The relationships between deposition parameters and coating properties were investigated. X-ray diffraction showed a phase transformation from CrN + Cr₂N + Cr → CrN + Cr → CrN and the CrN preferred orientation changed from (200) to (220) as N₂ pressure increased. Increasing bias voltage led to CrN preferred orientation changed from (200) to (220) and the formation of Cr₂N. XPS results indicated that chemical composition of the coatings changed as N₂ pressure increased but it changed little with bias voltage. The lower melting point of chromium nitride formed on target surface induced the increase of macroparticles and deposition rate with increasing N₂ pressure; and bias voltage had an obvious effect on reducing macroparticles of the Cr-N coatings. Residual stresses were measured by substrate curvature technique, and the changing tendency coincided with the microhardness of the coatings.     

Deposition of chromium aluminum nitride coatings by arc ion plating

Cr-Al-N ternary coatings were deposited by arc ion plating method using isolated Cr target and Al target. The influence of AlN content on the phase change was studied by synthesizing Cr1-xAlxN coatings with different x values. The effects of substrate negative bias on the surface morphology, deposition rate and phase structure were investigated. As the aluminum content increases, the structure of （Cr1-xAlx）N changes from Bl（NaCl） phase to B4（wurtzite） phase. The critical content of A1N solubilized in B 1 （NaCl） lattice is close to 0.7. With the increasing pulse negative bias, the deposition rate decreases constantly, the droplet contamination is more serious, the ion-etching effect on coating surface is more obvious, and the change of preferred orientation and the shift of XRD peak take place.     

电弧离子镀NiCoCrAlY涂层的组织结构及初期氧化

采用XRD，SEM，TEM和光激发荧光谱等技术对电弧离子镀制备的NiCoCrAlY涂层的组织结构和初期氧化的机理进行了研究．结果表明，电弧离子镀方法沉积的NiCoCrAlY涂层具有纳米晶体结构，呈明显的层状生长．真空退火后涂层内的层状结构消失，涂层组织更致密，晶粒明显长大，有孪晶出现．涂层在真空退火后表面已经生成一层很薄的以α-Al2O3为主的氧化膜，在高温氧化过程中，涂层表面的亚稳态氧化物θ-Al2O3先增多，然后逐渐转变为稳态的α-Al2O3，并对其相关机理进行了探讨．     

电弧离子镀CrTiN涂层的结构及耐腐蚀性能

采用电弧离子镀技术在模具钢H13表面沉积Cr_xTi_1-xN涂层,系统研究了不同Cr/Ti原子比对CrTiN合金化涂层结构、力学性能以及耐腐蚀性能的影响。结果表明:通过改变分离靶弧流实现CrTiN涂层中Cr/Ti原子比的有效调控,所制备的CrTiN涂层主要由面心立方结构(Cr, Ti)N和CrN组成,随着Cr/Ti原子比从1.1增加至1.8,涂层相结构由随机取向向(111)晶面优先生长转变。CrTiN合金化涂层显微硬度较CrN涂层得到明显提升,并随着固溶引起的晶格畸变程度变化而具有一个极大值。通过电化学阻抗谱和动电位极化曲线分析,当Cr/Ti原子比为1.4时,致密的Cr_0.59Ti_0.41N涂层具有最佳的耐腐蚀性能。     

Deposition of photocatalytic TiO2 and N-doped TiO2 films by arc ion plating

TiO2 and N-doped TiO2 films were deposited on the glass substrates by arc ion plating method. The results show that the deposition rate does not change with the increasing deposition time. The increase of mass flow rate of N2 gives rise to the increase of deposition rate. All as-deposited TiO2 and N-doped TiO2 films are amorphous. The anatase TiO2 phase with preferred orientation （101） is acquired by post-annealing at 400 ℃ for 2 h. The incorporation of N into the TiO2 films and the heat treatment extensively shift the band edge to the visible light region.     

Formation of nanocrystalline microstructure in arc ion plated CrN films

Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations of the films were carried out using X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HR-TEM). The results indicated that increasing ion bombardment by applying negative bias voltages resulted in the formation of defects in the CrN films, inducing microstructure evolution from micro-columnar to nanocrystalline. The microhardness and residual stresses of the films were also affected. Based on the experimental results, the evolution mechanisms of the film microstructure and properties were discussed by considering ion bombardment effects.     

Pulsed ion extraction from a hybrid plasma using a shunting arc discharge

A hybrid plasma is generated by combining a burst methane rf (195 kHz) plasma with a carbon shunting arc discharge. The shunting arc discharge triggers the rf methane plasma. As a result, the rf plasma is initiated over a wide range of ambient gas pressure from 0.045 Pa as a base pressure to a methane pressure of 1.26 Pa, at which the rf plasma is not self-ignited. When a target is immersed in the rf- and shunting arc-hybrid plasma, and a negative pulse voltage is applied to the target, carbon ions are extracted from the hybrid plasma. When the carbon shunting arc ionizes the methane gas, an rf plasma is initiated and the ionization of methane is significantly enhanced in the rf plasma. The plasma density in the hybrid plasma increases by a factor of approximately 5-9 compared to that of the shunting arc discharge.     

脉冲偏压电弧离子镀室温沉积非晶TiO2薄膜

采用脉冲偏压电弧离子镀技术在玻璃基片上室温制备了均匀透明的非晶TiO2薄膜,在0--900 V范围内改变脉冲偏压幅值,考察其对薄膜沉积速率、表面形貌和光学性能的影响.结果表明,随着脉冲偏压的升高,非晶薄膜沉积速率以-100 V为界先高后低;薄膜的吸收边先红移后蓝移,但光学带隙Eg基本无变化,约为3.27 eV;-300 V偏压时薄膜达到原子级表面平滑度,均方根粗糙度Rrms≈0.113 nm,因而薄膜折射率n也最高(nλ=550 nm达到已有报道的最高值2.51).     

Microstructure and residual stress of TiN films deposited at low temperature by arc ion plating

The TiN films were deposited on 316L stainless steel substrates at low temperature by arc ion plating. The influences of substrate bias voltage and temperature on microstructure, residual stress and mechanical properties of the films were investigated by EDS, SEM, XRD and nanoindenter tester, respectively. The results showed that the TiN films were highly oriented in (111) orientation with a face-centered cubic structure. With the increase of substrate bias voltage and temperature, the diffraction peak intensity increased sharply with simultaneous peak narrowing, and the small grain sizes increased from 6.2 to 13.8 nm. As the substrate temperature increased from 10 to 300 °C, the residual compressive stress decreased sharply from 10.2 to 7.7 GPa, which caused the hardness to decrease from 33.1 to 30.6 GPa, while the adhesion strength increased sharply from 9.6 to 21 N.     

基片偏压对电弧离子镀ZrN薄膜微结构和表面形貌的影响(英文)

在不同的基片偏压下利用电弧离子镀技术制备氮化锆薄膜,以考察基片偏压对氮化锆薄膜微结构和表面形貌的影响。利用XRD、EPMA和FE-SEM等技术对不同偏压时得到ZrN薄膜的相结构、成分和表面形貌进行表征。结果表明,薄膜中存在立方氮化锆和六方纯锆相;随着基片偏压的增大,薄膜的择优取向由(111)变为(200),最后变为(111),晶粒尺寸由30nm减小至15nm。同时发现,随着基片偏压的增大,薄膜微结构由明显的柱状特征变为致密的等轴晶特征,表明由偏压增强的离子轰击能有效抑制柱状晶生长;薄膜沉积速率和锆氮摩尔比随着基片偏压的增大先增大后减小,在-50V时达到最大。     

Determination of arc pressure and current density on the molten pool surface in plasma arc welding

A unified numerical model is developed to couple the plasma arc, weld pool and keyhole in a self consistent way. The plasma arc/anode interface and the melt/solid interface are treated specially, the VOF method is used to trace the moving keyhole wall, and the fluid flow and heat transfer in both the plasma arc and weld pool are numerically simulated. The distributions of current density and arc pressure on the weld pool surface during the keyhole formation process are analyzed using the coupled model. The predicted arc pressure and current density are compared with the experimentally measured results, and both are in good agreement.     

低压环境对等离子弧穿透能力的影响

设计了一套水冷铜阳极电弧力测试装置,测量了不同环境压力下等离子弧在穿透一定厚度工件后电弧压力的径向分布情况,研究了焊接电流、环境压力对于穿透电弧压力的影响规律. 结果表明,等离子穿透电弧压力在电弧中心区域最大,沿着径向从中心至边缘迅速减小. 在同一环境压力下,随着焊接电流的增加,等离子穿透电弧压力增大;当焊接电流相同时,在一定的压力范围内,随着环境压力的降低,等离子穿透电弧压力显著增大,且环境压力变化对于等离子穿透电弧压力的影响比焊接电流变化对其的影响更显著.