脉冲偏压占空比对TiSiN薄膜结构和性能的影响

采用电弧离子镀方法,通过改变脉冲偏压占空比在M2高速钢和单晶硅片基体上沉积TiSiN薄膜,研究脉冲偏压占空比对TiSiN薄膜形貌结构、元素成分、相结构、纳米硬度和耐蚀性能的影响。脉冲偏压占空比为30%时,TiSiN薄膜表面的大颗粒数目达到最大值832个,占空比为60%时,大颗粒数目减小到451个;脉冲偏压占空比从20%增加到50%,Si试样表面的膜层厚度从390.8 nm增加到2.339 μm;占空比为30%时,Si在薄膜中的含量最高为13.88at%,(220)晶面为择优取向,晶粒尺寸达到最小值5.05 nm,硬度达到28.34 GPa,自腐蚀电流密度达到最小0.5306 μA/cm²;占空比为40%时,(111)晶面为择优取向,Si的含量降低到最小值0.46at%;占空比为50%时,(111)晶面的晶粒尺寸达到13.22 nm,硬度达到最大值42.08 GPa,自腐蚀电位达到最高值-0.324 V(vs SCE)。40%以上的占空比可以减少大颗粒缺陷数量,降低TiSiN薄膜中的Si含量,改变TiSiN薄膜晶粒生长的择优取向,提高薄膜的硬度和耐蚀性能。     

脉冲偏压频率对TiSiN/TiAlN纳米多层膜结构和性能的影响规律

目的 研究脉冲偏压频率对TiSiN/TiAlN纳米多层薄膜结构和性能的影响,优化工艺参数,以提高薄膜的性能.方法 采用脉冲偏压电弧离子镀,在M2高速钢和单晶硅基底上以不同脉冲偏压频率沉积TiSiN/TiAlN纳米多层薄膜,采用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪和纳米压痕仪,研究脉冲偏压频率对TiSiN/TiAlN纳米多层薄膜的表面形貌、元素成分、截面形貌、相结构和纳米硬度的影响.结果 TiSiN/TiAlN纳米多层薄膜表面的大颗粒直径主要集中在1μm以下,随着脉冲偏压频率的变化,大颗粒的数量为184～234,所占面积为40.686～63.87μm2;主要元素为Ti元素和N元素,所占原子比分别为48％和50％,Si和Al元素的含量较少;多层结构不明显,截面形貌可观察到柱状晶的细化,80 kHz时出现片状化结构;以(111)晶面为择优取向,晶粒尺寸在20 nm左右;纳米硬度为28.3～32.3 GPa,弹性模量为262.5～286.8 GPa.结论 50 kHz时,TiSiN/TiAlN纳米多层薄膜表面大颗粒的数量最少,为184个;70 kHz时大颗粒所占面积最小,为40.686μm2;晶粒尺寸在50～60 kHz时发生细化,60 kHz时,晶粒尺寸达到最小值19.366 nm,纳米硬度和弹性模量分别达到最大值32.3 GPa和308.6 GPa,脉冲偏压频率的最佳频率范围为50～70 kHz.     

双电源低温渗氮工艺在316不锈钢上的应用

通过正交试验研究了交流脉冲电压、直流脉冲偏压和温度对316不锈钢表面硬度和渗层厚度的影响,获得了双电源低温渗氮最佳工艺参数。通过光学显微镜(OM)、X射线衍射仪(XRD)、显微硬度计、电化学工作站以及摩擦磨损试验机等研究了最佳工艺下渗氮试样的性能。结果表明,影响渗氮试样性能因素的顺序为:交流脉冲电压＞温度＞直流脉冲偏压。最佳工艺参数为交流脉冲电压360 V,直流脉冲偏压270 V,温度380 ℃。对最佳工艺制备的试样与单电源进行对比:渗层厚度为43.4 μm,是单电源的8.5倍;表面硬度为1350 HV0.025,是单电源的3.1倍;自腐蚀电位由－256 mV(vs SCE,下同)提高到－180 mV;自腐蚀电流密度从13.90 μA/cm² 降低到0.45 μA/cm²;摩擦因数从0.55降低到0.42。双电源渗氮速率的提高是由于高能离子轰击引起的表面结构缺陷和渗氮气体的高度离解。     

Si含量对电弧离子镀Ti-Al-Si-N薄膜组织结构和力学性能的影响

利用磁过滤电弧离子镀技术在高速钢基体上制备了不同Si含量的Ti-Al-Si-N薄膜,研究了Si含量对薄膜组织结构以及力学性能的影响.结果表明,Ti-Al-Si-N薄膜主要由晶态TiAlN和非晶态的Si₃N₄组成,随着Si含量的增加,XRD衍射峰强度减弱,晶粒尺寸减小;薄膜的显微组织也由明显的柱状晶转变为致密的纳米晶结构.利用纳米硬度仪对薄膜的硬度和弹性模量进行了分析,结果表明,薄膜的硬度和弹性模量有着相似的变化趋势,随着Si含量的增加,两者都先增加,当Si含量达到一定程度时.它们会逐渐稳定在一定范围内,而后又随Si含量的继续增加呈下降趋势.通过划痕测试对薄膜结合强度进行了分析,结果表明,薄膜与基体的结合强度随Si含量的增加先减小而后增加.     

基体偏压对PEMFC不锈钢双极板Cr-N改性涂层性能的影响

目的 提高SS316L双极板的耐腐蚀性与导电性。方法 使用脉冲直流磁控溅射技术,改变基体负偏压,于SS316L双极板上制备了Cr-N薄膜。通过扫描电子显微镜、XRD衍射仪、电子探针分析仪对薄膜的成分和结构进行了检测分析。通过接触电阻测试、电化学腐蚀测试和接触角测试表征了薄膜的导电性、耐腐蚀性和疏水性。结果 薄膜的结构主要由Cr和Cr₂N组成,各组试样的成分相近。随着沉积过程中基体负偏压的增大,薄膜结构更加致密。镀膜试样的耐腐蚀性均好于基材SS316L,基体负偏压为400 V时,测得试样的腐蚀电流密度最低,为3.49×10^-7 A/cm²。镀膜试样的导电性均好于基材SS316L,基体为负偏压200 V时,双极板的导电性最好,表面接触电阻为8.02 mΩ·cm²。基体负偏压继续增大,双极板的接触电阻会有所下降。结论 随着沉积偏压的增加,薄膜中的N含量略有增加。薄膜沉积对SS316L双极板的导电性、耐腐蚀性和疏水性有明显的提高,较于基材自腐蚀电位提升了411 mV,腐蚀电流密度下降了2个数量级。沉积时较高...     

等离子体密度调控CrN薄膜结构改性Ti6Al4V双极板

目的 满足质子交换膜燃料电池双极板的使用要求。方法 采用热丝增强等离子体磁控溅射技术,通过改变热丝放电电流调控溅射等离子体密度,在Ti6Al4V（TC4）合金表面制备了氮化铬（CrN）薄膜。结果 随着热丝放电电流从0A增加至32A,真空腔内等离子体密度增强,-50V偏压下基体偏流密度从0.07 mA/cm²增至0.7 mA/cm²。CrN薄膜择优取向从低应变能的（111）转变成表面能更低的（200）择优取向。薄膜表面形貌由较疏松的四棱锥型转变成致密球形;无热丝时,CrN薄膜显示有铬的（110）衍射峰且铬原子数分数为52.16%,为富金属薄膜。热丝放电电流为16 A和32 A时,Cr N薄膜中的铬原子数分数分别降至50.79%和49.82%,且无Cr的衍射峰,即逐渐转变为贫铬。采用热丝辅助磁控溅射,将使氮气离化率增大,活性增强,引起薄膜贫铬。模拟双极板工作环境下,与TC4腐蚀电流密度1.5×10^-8 A/cm²相比,CrN薄膜的腐蚀电流密度由无热丝的3×10^-5 A/cm     

脉冲偏压占空比对TiCrN薄膜微观结构和性能的影响规律*

随着先进制造领域对高速钢材料切削性能和加工性能的要求越来越高，迫切需要利用氮化物薄膜来提高基体材料的硬度和耐磨性等综合性能，延长高速钢材料的使用寿命。通过 TiCrN 薄膜提升高速钢材料的使役性能，研究脉冲偏压占空比对 TiCrN 薄膜微观结构和性能的影响规律，实现薄膜沉积工艺的优化。采用电弧离子镀方法，通过改变脉冲偏压占空比在 M2 高速钢基体和单晶硅片上沉积 TiCrN 薄膜。研究发现，脉冲偏压占空比的增大有助于减少膜层表面大颗粒数量，改善膜层表面质量；占空比从 10%增加到 60%，TiCrN 薄膜厚度先增大后减小，30%占空比时，TiCrN 薄膜的厚度达到最大值 623.8 nm， 60%占空比时，TiCrN 薄膜的厚度达到最小值 517.4 nm。当脉冲偏压占空比为 10%时，Cr 元素含量为 33.9 at.%，晶粒尺寸达到最小值 12.692 nm，纳米硬度和弹性模量分别为 29.22 GPa 和 407.42 GPa。当脉冲偏压占空比为 30%时，Cr 元素含量达到最小值 33.07 at.%，此时 TiCrN 薄膜晶粒尺寸达到最大值 15.484 nm，纳米硬度达到最小值 25.38 GPa，稳定摩擦因数达到最大值 0.9。所制备的 TiCrN 薄膜均以（220）晶面为择优取向，晶粒尺寸在 12.692~15.484 nm，纳米硬度都在 25 GPa 以上， 是 M2 高速钢的 2.8 倍以上。在脉冲偏压占空比为 20%时，TiCrN 薄膜摩擦因数最小为 0.68，磨痕宽度为 0.63 mm，自腐蚀电位达到最大值-0.330 V（vs SCE），自腐蚀电流密度达到最小值 0.255 μA / cm² ，腐蚀速率最低，耐腐蚀性能最强。与 M2 高速钢基体相比，TiCrN 薄膜的硬度、耐腐蚀和摩擦磨损性能都显著提升，Cr 元素和离子轰击作用是影响 TiCrN 薄膜性能的主要因素。研究结果为硬质薄膜工艺优化提供了一定的试验依据，TiCrN 薄膜在刀具材料性能提升方面有较好的应用前景。     

脉冲偏压占空比对TiN/TiAlN多层薄膜微观结构和硬度的影响

目的研究脉冲偏压占空比对TiN/TiAlN多层薄膜微观结构和硬度的影响规律。方法利用脉冲偏压电弧离子镀的方法,改变脉冲偏压占空比,在M2高速钢表面制备5种TiN/TiAlN多层薄膜,对比研究了薄膜的微观结构、元素成分、相结构和硬度的变化规律。结果 TiN/TiAlN多层薄膜表面出现了电弧离子镀制备薄膜的典型生长形貌,随着脉冲偏压占空比的增加,薄膜表面的大颗粒数目明显减少。此外,脉冲偏压占空比的增加还引起多层薄膜中Al/Ti原子比的降低。结论 TiN/TiAlN多层薄膜主要以(111)晶面择优取向生长,此外还含有(311),(222)和(200)晶相结构。5种多层薄膜的纳米硬度均在33GPa以上,当脉冲偏压占空比为20%时,可实现超硬薄膜的制备。     

脉冲偏压对复合离子镀(Ti,Cu)N 薄膜结构与性能的影响

目的 (Ti,Cu)N薄膜是一种新型的硬质涂层材料,关于其结构和性能的研究报道还较少。研究脉冲偏压对(Ti,Cu)N薄膜结构与性能的影响规律,以丰富该研究领域的成果。方法将多弧离子镀和磁控溅射离子镀相结合构成复合离子镀技术,采用该技术在不同脉冲偏压下于高速钢基体表面制备(Ti,Cu)N薄膜。分析薄膜的微观结构,测定沉积速率及薄膜显微硬度,通过摩擦磨损实验测定薄膜的摩擦系数。结果在不同偏压下获得的(Ti,Cu)N薄膜均呈晶态,具有(200)晶面择优取向,当脉冲偏压为-300 V时,薄膜的择优程度最明显。随着脉冲偏压的增加,薄膜表面大颗粒数量减少且尺寸变小,表面质量提高;沉积速率呈现先增大、后减小的趋势,在脉冲偏压为-400 V时最大,达到25.04 nm/min;薄膜硬度也呈现先增大、后减小的趋势,在脉冲偏压为-300 V时达到最大值1571.4HV。结论脉冲偏压对复合离子镀(Ti,Cu)N薄膜的表面形貌、择优取向、沉积速率和硬度均有影响。     

脉冲偏压对TiAlCN薄膜结构与力学性能的影响

利用多弧离子镀-磁控溅射复合技术通过改变脉冲偏压在Si片与SS304基体表面制备了TiAlCN薄膜,研究了不同脉冲偏压对薄膜结构和力学性能的影响。薄膜成分、表面形貌、相结构及力学性能分别利用能量弥散X射线谱(EDS)、扫描电镜(SEM)、X射线衍射(XRD)和纳米压痕仪等设备进行表征。结果表明,随着脉冲负偏压的增加,薄膜中Ti元素的含量先减小后增大,而Al元素有相反的变化趋势。适当增大脉冲偏压,薄膜表面颗粒、凹坑等缺陷得到明显改善。物相分析表明TiAlCN薄膜主要由(Ti,Al)(C,N)相,Ti4N3-x相和Ti3Al相组成。薄膜平均硬度与弹性模量随脉冲负偏压的增加先增大后减小,在负偏压-200 V时达到最大值分别为36.8 GPa和410 GPa。     

Growth and characterization of tetragonal bismuth ferrite–lead titanate thin films

Thin films of tetragonal bismuth ferrite–lead titanate (1 − x)BiFeO₃–xPbTiO₃ with x = 0.9–0.7 were prepared by pulsed laser deposition (PLD). The films exhibit a dense columnar grain growth. XRD analysis reveals that the films have a perovskite structure and exhibit a preferred (1 1 1) texture. The film microstructure was studied using SEM. The ferroelectric properties of the films are discussed in the light of polarization-field hysteresis behaviour and impedance spectroscopy. The remanent polarization values ranged between 2P_r  45 and 60 μC cm⁻² at a field amplitude of 500 kV cm⁻¹ and −10 °C, while the dielectric permittivity of the films ranged between 375 and 1096 at a frequency of 2 kHz.     

Characterisation of oxide films produced by plasma electrolytic oxidation of a Ti–6Al–4V alloy

The paper discusses processing and property aspects of oxide films formed on a Ti–6Al–4V alloy by AC plasma electrolytic oxidation (PEO) in aqueous solutions containing aluminate, phosphate, silicate and sulfate anions and some of their combinations. Structure, composition, mechanical tribological and corrosion resistant characteristics of the films formed are studied by SEM, XRD and microhardness analyses, and by scratch, impact, pin-on-disc friction and potentiodynamic corrosion testing. It is found that the films produced from the aluminate–phosphate electrolyte are dense and uniform and are composed mainly of Al₂TiO₅ and TiO₂ phases of the rutile form. The films possess a beneficial combination of 50–60 μm thickness, 575 kg/mm² hardness and high adhesion and provide a low wear rate (3.4×10⁻⁸ mm³/Nm) but a relatively high friction coefficient of μ=0.6–0.7 against steel, caused by material transfer from the counterface. A minimum friction coefficient of μ=0.18 is recorded during the testing of softer rutile–anatase films, 7 μm thick, produced from a phosphate electrolyte. Both of these types of film show good corrosion resistance in NaCl and physiological solutions, where the corrosion current is approximately 1.5 orders of magnitude lower than that of the uncoated substrate. SiO₂/TiO₂-based films with 70–90 μm thickness and high bulk porosity produced from silicate and silicate–aluminate electrolytes demonstrate better corrosion behaviour in H₂SO₄ solution, due to the greater chemical stability of the film phase components in this environment.     

脉冲偏压对电弧离子镀Ti/TiN纳米多层薄膜显微硬度的影响

采用脉冲偏压电弧离子镀方法在高速钢基体上沉积Ti／TiN纳米多层薄膜,采用正交实验法设计脉冲偏压电参数,考察脉冲偏压对Ti／TiN纳米多层薄膜显微硬度的影响．结果表明,在所有偏压参数（脉冲偏压幅值、占空比和频率）和几何参数（调制周期和周期比）中,脉冲偏压幅值是影响显微硬度的最主要因素;当沉积工艺中脉冲偏压幅值为900V、占空比为50％及频率为30kHZ时,薄膜硬度可高达34．1GPa,此时多层膜调制周期为84nm,TiN和Ti单元层厚度分别为71和13nm;由于薄膜中的单层厚度较厚,纳米尺寸的强化效应并未充分体现于薄膜硬度的贡献中,硬度的提高主要与脉冲偏压工艺,尤其是脉冲偏压幅值对薄膜组织的改善有关．     

Rutile-type titanium oxide films synthesized by filtered arc deposition

A filtered arc-deposition system was used to synthesize titanium oxide films by evaporating titanium ions in an oxygen environment. Fourier transform infrared spectroscopy and X-ray diffraction analysis show that the films exhibit the rutile-type structure. X-ray photoelectron spectroscopy reveals that a small amount of Ti²⁺ and Ti³⁺ still exists although Ti⁴⁺ is the main component in the films. The preferred orientation of the films is dependent on the substrate bias and oxygen pressure. Titanium oxide films with (101) and (002) preferred orientation were prepared by changing substrate bias and oxygen pressure. Ultraviolet–visible absorption spectroscopy was used to determine the optical band gap of the prepared films. The results show that the band gap of the films prepared under zero substrate bias is 2.39 eV. When the substrate bias is larger than −100 V, the optical band gap of the films is about 3.33 eV.     

Electrical properties of polyimide thin films formed by the vapor deposition polymerization method

Thin films of polyimide (PI) were fabricated by a vapor deposition polymerization method (VDPM) and studied for their insulator characteristics in semiconductor devices. Polyamic acid (PAA) thin films fabricated by vapor deposition polymerization (VDP) from PMDA (pyromellitic dianhydride) and DDE (4,4′-diaminodiphenyl ether) were converted to PI thin films by thermal curing. The appropriate curing temperature was 300 °C. From TG-DTA (Thermo Gravimetry-Differential Thermal Analysis), the PI thin films can endure 230 °C for 20 000 h. They exhibited a relative permittivity of 3.9–3.5 and a dissipation loss factor of 0.008 at frequency of 10 kHz in the temperature range from 25 to 200 °C. The resistivity was approximately 3.2×10¹⁵ Ωcm and the dielectric breakdown strength was 4.61 MV/cm.     

碳钢超声磷化及在模拟干热岩地热水中的耐蚀性能

采用环境友好的硫酸羟胺为主要促进剂,避免使用强氧化性物质,并以超声处理来改进磷化工艺。通过动电位极化曲线方法研究了超声、促进剂、pH值和磷化时间对磷化膜耐蚀性能的影响。结果表明,超声处理能够细化磷化颗粒,提高其耐蚀性能。pH值和磷化时间显著影响磷化膜的耐蚀性,需保持在较优的范围。采用电化学阻抗谱研究了优化工艺得到的磷化膜在模拟干热岩地热水中的耐蚀性,发现其电荷转移电阻由碳钢的1.44×10³ Ωcm²增加到3.39×10⁶ Ωcm²。     

Role of rf power on the properties of undoped SnOx films deposited by rf-PERTE at low substrate temperature

Transparent and conductive undoped tin oxide (SnO_x) thin films were deposited at low substrate temperature (< 140 °C) by radio frequency (rf) plasma enhanced reactive thermal evaporation (rf-PERTE) of tin (Sn) in the presence of oxygen The undoped SnO_x films were not submitted to any post-annealing treatments. The influence of rf power variation on the optical, electrical and structural properties of the as-grown films is presented. A variation in the films' structure was verified with the increase of rf power. Undoped SnO_x films, 90 nm average thick, deposited at rf power range of 60–70 W are nanocrystalline, show a conductive behaviour, an average visible transmittance of ≥ 80% and a maximum electrical conductivity of about 34.6 (Ω cm)^− 1. Films deposited at lower values of rf power (40 W) are amorphous and exhibit a semiconductive behaviour, showing an electrical conductivity of about 7.54 × 10^− 1 (Ω cm)^− 1. As a low substrate temperature deposition process is used, SnO_x thin films can be obtained on a wide range of substrates.     

Computer-aided thermodynamic study of solid Co---Pd alloys by Knudsen cell mass spectrometry, and calculation of the phase diagram

F.c.c. solid Co---Pd alloys have been investigated thermodynamically by means of computer-aided Knudsen cell mass spectrometry. Thermodynamic evaluation has been performed by applying the “digital intensity ratio” method. The thermodynamic excess properties can be described algebraically by means of thermodynamically adapted power series with two adjustable parameters, i.e. C₁^G (−20 810 + 9.608T) J mol⁻¹) and C₂^G (−30 720 + 6.78T) J mol⁻¹). At 1470 K, f.c.c. solid Co---Pd alloys are characterized by negative molar excess Gibbs energies G^E, exothermic molar heats of mixing (H^E) and small negative molar excess entropies S^E. At 1470 K, the minimum G^E value is −4600 J mol⁻¹ (61.9 at.% Pd), the minimum H^E value is −9400 J mol⁻¹ (59.5 at.% Pd) and the minimum S^E value is −3.3 J mol⁻¹ K⁻¹ (55.9 at.% Pd). The thermodynamic activities of Co show small positive deviations from the ideal case for the Co-rich alloys (x_Pd < 0.34), and negative deviations from Raoults' law for alloys with higher Pd contents. The Pd activities a_Pd show negative deviations from the ideal case for all compositions. The phase diagram has been computed by means of a generally applicable procedure for the calculation of the equilibrium compositions of coexisting phases. This was achieved using the results of this work, thermodynamic data from earlier mass spectrometric studies on the liquid phase, and literature data for the heat capacities and enthalpies of Co and Pd.