工艺参数对Ni-ZrO2纳米复合镀层性能的影响

用电沉积方法在铜表面制备了Ni-ZrO2纳米复合镀层。研究了工艺参数对复合镀层的硬度、耐磨性、耐蚀性的影响。结果表明,镀层硬度随阴极电流密度、镀液温度的增大均呈现先增大后减小的趋势;而随镀液中纳米ZrO2的添加量增加,镀层的硬度逐渐增大;镀层的耐磨性随这几个工艺参数的增加先增加后减小;镀层的耐蚀性随着电流密度的升高先下降再升高,随着镀液中纳米ZrO2添加量、镀液温度的增加,镀层的耐蚀性先升高再下降。本工作中最佳的工艺参数为纳米ZrO2添加量8g/L,阴极电流密度3A/dm2,镀液温度50℃左右。     

激光重熔对 Fe-ZrO2复合镀层形貌及性能的影响

目的进一步提高电沉积Fe-ZrO2纳米复合镀层的性能。方法在45#钢基体表面电沉积FeZrO2纳米复合镀层,并进行激光重熔后处理。通过正交实验分析激光重熔参数对镀层显微硬度、结合力和表面形貌的影响,并优化重熔工艺。结果优化的工艺为:电流150 A,脉宽8 ms,频率15 Hz,扫描速率250 mm/min,负离焦量2 mm。镀层经激光重熔后,硬度提高,纳米颗粒得到了细化,与基体形成了冶金结合。结论激光重熔可以改善Fe-ZrO2纳米复合镀层的微观形貌,提高其性能。     

热处理对Ni-TiN纳米复合镀层结构和性能的影响

目的进一步提高脉冲-超声电沉积Ni-TiN纳米复合镀层的显微硬度,改善镀层的耐磨性。方法利用扫描电镜、X射线衍射仪、显微硬度计、摩擦磨损仪器,对经200~600℃热处理后Ni-TiN纳米复合镀层的表面形貌、内部组织结构、显微硬度和磨损性能进行检测,研究了热处理方式对复合镀层的表面形貌、晶相组织、显微硬度和耐磨性的影响。结果经300℃保温1.5 h后的镀层表面最为平整和光滑。同时镀层开始实现非晶态向晶态演变,并且镀层硬度最高,其值高达815HV。随热处理温度的升高,镀层晶粒变大,表面平整度降低。经600℃热处理,保温1.5h后,镀层的耐磨性最佳,磨损量仅为13.2 mg。结论经热处理之后,镀层硬度得到一定程度的提高,主要是TiN纳米粒子起到弥散和细晶强化作用。耐磨性得到有效改善,主要是由于镀层韧性、镀层和基体间的结合力得到提高,镀层形成一层致密的氧化膜的原因。     

热处理温度对Ni-W-P/TiO2复合镀层微观结构及性能的影响

采用化学镀的方法在2024铝合金表面制备了Ni-W-P/TiO₂复合镀层,基于差示扫描量热法(DSC)结果,确定了复合镀层热处理温度范围为350~550℃。利用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)、维氏硬度测试仪、滑动磨损试验机和电化学工作站等研究了热处理温度对Ni-W-P/TiO₂复合镀层的形貌、组织结构、耐磨性与耐蚀性的影响。结果表明:随着热处理温度的升高,Ni-W-P/TiO₂复合镀层表面变得平整且致密,但热处理温度超过450℃时,镀层表面晶粒变得粗大;截面形貌观察发现,复合镀层与基体结合良好,无明显裂纹;随着热处理温度升高,Ni-W-P/TiO₂复合镀层由非晶态结构向晶态结构转变,在450℃热处理后镀层析出Ni₃P相,此时镀层的显微硬度最大(849.1 HV0.1),平均摩擦系数最小(0.069),磨损速率最低(0.138 mg/min);在400℃热处理后镀层的耐蚀性最好,高于400℃热处理后,镀层的耐蚀性有所下降。     

Zn/纳米CeO2复合镀层的制备及电化学性能研究

纳米粒子具有一系列特殊的性能,采用电镀的方法在镀层中添加纳米颗粒可改善镀层的某些性能.利用纳米稀土氧化物在基体相中的补强作用以及可能赋予镀层某些新性能的特点,采用复合电镀的方法制备了Zn/纳米CeO2复合镀层,分析了镀液中CeO2颗粒悬浮量、阴极电流密度和镀液温度等因素对复合镀层中纳米CeO2复合量和膜层质量的影响,用正交试验法优选了各工艺参数.采用电化学方法研究了Zn/纳米CeO2复合镀层的耐蚀性.结果表明:复合镀层晶粒细小,平整光滑,显微组织均匀、致密,且镀层耐蚀性能比相同电镀条件下制得的纯锌镀层有所提高.     

脉冲沉积占空比对Ni-Co-ZrO2复合镀层摩擦磨损性能的影响

通过脉冲电沉积的方法制备了Ni-Co-ZrO2复合镀层,确定了最佳的镀液配方和工艺参数,利用扫描电镜、能谱仪分别观察和分析了复合镀层的显微形貌及成分组成,探讨了脉冲占空比对Ni-Co-ZrO2复合镀层耐磨性能的影响。结果表明:所制备的复合镀层厚度约为55μm,镀层与基体之间结合良好,ZrO2颗粒均匀分布于镀层内部。ZrO2颗粒的加入改善了镀层的显微形貌,显著提高了镀层的耐磨性能。随着占空比的降低,沉积晶粒细化,复合镀层的耐磨性能得以改善,最佳占空比为40%。     

稀土对化学镀镍磷合金镀层性能的影响

研究了在酸性镀液中制得的镍磷合金镀层的组织结构，探讨了稀土离子(La^3 、Y^3 )和稀土氧化物(CeO2、Y2O3)对化学镀镍磷的影响及作用机理，通过正交试验取得了稀土复合镀镍磷合金的最佳配方。同时，研究了在镀液中加入稀土元素后镀层的热处理工艺及强化机制。结果表明，酸性镀液中所得镀层为非晶态结构的胞状组织，稀土与镍共沉积在镀层中可提高镀层硬度、耐磨性，加入复合稀土元素的镀层耐磨性优于单一稀土镀层。稀土元素增强了热处理强化的效果，并使镀层与基体间产生新相FeNi3，镀层与基体的结合力明显增加。     

电沉积方式对Ni-SiC纳米复合镀层性能的影响

目的通过研究电沉积方式对Ni-SiC纳米复合镀层性能的影响,进而改善Ni-SiC纳米复合镀层的性能。方法采用直流电沉积和脉冲电沉积分别制备Ni和Ni-SiC纳米复合镀层,使用扫描电镜和能谱仪研究镀层的表面形貌和成分,通过测量施镀前后镀件质量差计算沉积速率,采用硬度计测量了镀层的硬度,利用极化曲线和电化学阻抗方法研究镀层在3.5%NaCl水溶液中的耐腐蚀性能,分析了直流电沉积方式和脉冲电沉积方式对镀层各项性能的影响。结果脉冲电沉积方式制备的Ni-SiC纳米复合镀层的表面形貌更加致密、均匀、光滑,镀层硬度为616.3HV,自腐蚀电流为9.56×10~(-6) A,比直流电沉积制备的Ni-SiC纳米复合镀层的硬度和耐蚀性能均有所提高。结论电沉积方式对复合镀层的性能有很大影响,脉冲电沉积方式制备的Ni-SiC纳米复合镀层具有更好的性能。     

La2O3/CeO2颗粒尺寸对Ni-La2O3/CeO2复合电镀层高温氧化性能的影响（英文）

通过向普通硫酸镍电镀液中添加一定含量的微米或纳米La2O3/CeO2颗粒,采用复合电镀制备微米或纳米La2O3/CeO2颗粒分布的Ni基复合镀层,并研究La2O3/Ce O2颗粒尺寸对Ni-La2O3/CeO2复合镀层在1000°C抗氧化性能的影响。结果表明:与普通Ni镀层相比,Ni-La2O3/CeO2复合镀层中的La2O3/Ce O2颗粒通过溶解扩散进入氧化膜中,阻碍Ni的外扩散,从而降低氧化速度;此外,与La2O3/CeO2纳米颗粒相比,La2O3/Ce O2微米颗粒在氧化初期还起到扩散障碍层的作用,对阻碍Ni的外扩散具有更强的作用。     

电解液Ca/P比对微弧氧化钛合金涂层结构及性能的影响

采用微弧氧化技术在Ti-13Nb-13Zr合金表面制备HA/TiO₂复合涂层。通过改变电解液中Ca/P比值,研究不同Ca/P比对微弧氧化涂层的相组成及组织变化,以及对耐磨性、耐蚀性与体外生物活性的影响。结果表明:随着电解液Ca/P比增大,涂层粗糙度及孔隙率增大。涂层相组成以锐钛矿及金红石为主,金红石相含量随着电解液Ca/P比增大而增大。乙酸钙含量为35 g/L的电解液制备的CA35涂层厚度达80.59μm,表面Ca/P比为1.98,表现出最好的耐磨耐蚀性能。与基体相比,CA35涂层平均摩擦系数约为0.19,下降了43%。采用Pt参比电极和质量分数0.9%NaCl测试溶液对涂层的耐蚀性进行检测。CA35涂层的腐蚀电流密度为4.94μA/cm²,腐蚀电位为-221.73 mV。CA35涂层在Kokubo溶液中产生矿化产物的速度最快。研究发现适当提高电解液Ca/P比能有效促进HA的形成,提高涂层的耐磨耐蚀性能,过高的Ca/P比会导致涂层性能下降。此外,对Ca/P比对涂层性能的影响机理进行了探讨。     

添加CeO_2对MoS_2基复合涂层摩擦学性能的影响

针对MoS_2基复合涂层耐磨性差和承载能力低的问题,以不同含量(质量分数)的CeO_2作为添加剂,采用喷涂法在GCr15钢表面制备MoS_2基复合涂层。利用摩擦磨损试验机和划痕仪分别研究涂层摩擦磨损性能和结合强度,并借助金相显微镜对涂层磨损形貌进行表征。结果表明:添加适量CeO_2可以改善涂层的摩擦磨损性能,其最佳含量为2%,此时摩擦因数和磨损量均最小,分别为0.232和0.011 3 mm~3;同时结合强度从22 N提高到28.29 N。涂层磨损量随载荷的增大而增大;而载荷小于8 N时,涂层的摩擦因数随载荷的增大而减小,当载荷大于8 N时,摩擦因数又有回升趋势。添加稀土后涂层的承载能力有明显提高。未添加稀土时,涂层产生严重剥离,并发生磨粒磨损;添加2%CeO_2后,涂层发生轻微磨粒磨损,耐磨性得到显著提高。     

WC和Al2O3对氩弧熔覆FeAlCoCrCuTi0.4高熵合金涂层组织和耐冲蚀性能影响

利用氩弧熔覆技术制备了FeAlCoCrCuTi_0.4,WC/Al₂O₃-FeAlCoCrCuTi_0.4高熵合金涂层,并通过XRD,SEM,EDS,硬度测试和冲蚀磨损测试等方法,探究了WC和Al₂O₃的添加对FeAlCoCrCuTi_0.4高熵合金涂层显微组织和性能的影响.结果表明,通过氩弧熔覆技术所制备的合金涂层表面成形性良好,无孔洞、裂纹等缺陷产生,与基体呈高强度冶金结合.WC和Al₂O₃的添加对涂层稀释率的降低有显著作用.三种涂层都是主要由Bcc相（Fe-Cr固溶体）构成,晶粒以胞状树枝晶形式存在.添加WC后,晶粒细化明显,在各种强化作用下涂层硬度为685.8 HV.且WC和Al₂O₃的添加显著提高了涂层耐冲蚀磨损性能,耐磨性几乎可以达到FeAlCoCrCuTi_0.4高熵合金涂层的2倍.     

激光熔覆AlxNbMn2FeMoTi0.5高熵合金涂层的组织与性能

使用激光熔覆技术在Q235钢基体上制备AlxNbMn2FeMoTi0.5高熵合金涂层,期望借此提高干切削技术适用刀具表层的硬度和耐磨性.经过初步筛选之后,主要研究了AlxNbMn2FeMoTi0.5(x=1、1.5、2)高熵合金涂层体系,并采用XRD和3D激光扫描成像等手段分析了不同Al含量的AlxNbMn2FeMoT...     

Effects of critical plasma spray parameter and spray distance on wear resistance of Al2O3-8 wt.%TiO2 coatings plasma-sprayed with nanopowders

Effects of plasma spraying conditions on wear resistance of nanostructured Al₂O₃-8 wt.%TiO₂ coatings plasma-sprayed with nanopowders were investigated in this study. Five kinds of nanostructured coatings were plasma-sprayed on a low-carbon steel substrate by varying critical plasma spray parameter (CPSP) and spray distance. The coatings consisted of fully melted region of γ-Al₂O₃ and partially melted region, and the fraction of the partially melted regions and pores decreased with increasing CPSP or decreasing spray distance. The hardness and wear test results revealed that the hardness of the coatings increased with increasing CPSP or decreasing spray distance, and that the hardness increase generally led to the increase in wear resistance, although the hardness and wear resistance were not correlated in the coating fabricated with the low CPSP. The main wear mechanism was a delamination one in the coatings, but an abrasive wear mode also appeared in the coating fabricated with the low CPSP. According to these wear mechanisms, the improvement of wear resistance in the coating fabricated with the low CPSP could be explained because the improved resistance to fracture due to the presence of partially melted regions might compensate a deleterious effect of the hardness decrease.     

ZrO2 加入量对Zr-8Al合金化学复合镀性能的影响

对Zr-8Al合金进行了化学复合镀Ni-P-ZrO_2处理,并研究了不同ZrO_2粒子加入量制备的复合镀层的显微结构、显微硬度、耐磨性和抗蚀性。结果表明,与单纯化学镀Ni-P镀层相比,Ni-P-ZrO_2复合镀层的显微硬度值显著提高,ZrO_2的添加量为4 g/L获得复合镀层显微硬度最高,耐磨性好;在3.5%(质量分数)NaCl溶液中耐蚀性虽有所下降,但腐蚀后镀层完整,仍具有较好的抗蚀性。Zr-8Al合金表面采用4 g/L ZrO_2粒子制备的Ni-P-ZrO_2复合镀层兼具很好的耐磨性和较好的耐蚀性,适用于既要耐磨又要抗蚀的空间活动构件。     

Microstructure and characterization of La2O3 and CeO2 doped diamond-like carbon nanofilms

Seven kinds of hydrogen-free La₂O₃ and CeO₂ doped DLC films with thickness of 220-280 nm were deposited on Si (100) substrates by unbalanced magnetron sputtering. Nanoparticles with diameter of 20-30 nm are formed on the surface of films. The surface roughness Ra of films is in the range of 1.5-2.0 nm. C, La, Ce and O elements distribute uniformly along the depth direction, and C, La, and Ce elements diffuse into the Si substrate at the interface. X-ray photoelectron spectroscopy confirms that the La₂O₃ and CeO₂ form within the DLC amorphous films, and Raman spectra indicate the obvious amorphous characteristics of DLC films. High-resolution transmission electron microscopy shows the nanocrystallines structure with diameter of 2-3 nm of 16% La₂O₃ and 10% CeO₂ doped DLC films, and Fourier transformation spectroscopy also exhibits the obvious crystalline characteristics. In this work, the microstructure of two kinds of rare earth oxides doped DLC composite films is measured and analyzed.     

Preparation and properties of sintered molybdenum doped with La2O3/MoSi2

Sintered Mo with the addition of La₂O₃/MoSi₂ was prepared via the process of solid–solid doping + powder metallurgy. X-ray diffraction experiment, hardness test, three-point bending test and high-temperature tensile test were carried out to characterize the samples. The XRD pattern of a typical sample shows that the sintered Mo was mainly composed of Mo, La₂O₃ and Mo₅Si₃. Mo₅Si₃ was probably formed through the reaction between MoSi₂ and the Mo matrix. Densities and fracture toughnesses of both doped Mo and pure Mo were measured and contrasted. Sintered Mo with the addition of 0.2 wt% La₂O₃/MoSi₂ has the highest toughness, while more addition of La₂O₃/MoSi₂ has smaller effect on improving toughness or even embrittles Mo. The results of three-point bending test and high-temperature tensile test show that the bending strength and high-temperature tensile strength of doped Mo are both higher than those of pure Mo. The formation of Mo₅Si₃ improves the high-temperature strength. The La₂O₃/Mo₅Si₃ dispersed in the Mo matrix refined the grains, and thus strengthened the Mo matrix by dispersion strengthening and grain refinement.