Zr掺杂类金刚石薄膜摩擦性能及耐腐蚀性能的影响

目的改善不锈钢摩擦性能及耐腐蚀性能。方法通过线性阳极层离子源辅助非平衡磁控溅射法,制备了不同Zr含量的类金刚石(DLC)薄膜,采用扫描电子显微镜、拉曼光谱仪、纳米硬度仪、高温销盘磨损仪、电化学工作站,对薄膜的化学成分、显微结构、纳米硬度、薄膜摩擦性能及耐腐蚀性能进行测试研究。结果随着Zr靶功率的增大,Zr含量线性增加。Zr含量从4.9%增加至16.3%时,I_D/I_G增大,薄膜硬度从12.1 GPa逐渐下降至8.4 GPa;Zr含量增大至21.2%时,I_D/I_G减小,薄膜硬度增大至11.4 GPa。涂镀类金刚石薄膜的不锈钢基体比无涂层的不锈钢基体有更低的摩擦系数,更好的耐磨损性能。Zr掺杂DLC薄膜的最小摩擦系数为0.07。Zr含量从4.9%增加至16.3%,DLC薄膜的耐腐蚀性能减弱;Zr含量继续增加,DLC薄膜的耐腐蚀性能增强。当Zr含量不大于11.9%时,沉积Zr掺杂DLC膜的不锈钢基体的耐腐蚀性能比不锈钢基体的更强。结论 Zr含量不大于11.9%时,Zr掺杂类金刚石薄膜既可以有效地改善不锈钢基体的摩擦磨损性能,又可以大幅提高耐腐蚀性能。     

双层辉光等离子制备TiN渗镀层的耐蚀性能

利用双层辉光等离子表面合金化技术,在Q235钢表面直接合成TiN渗镀层,该渗镀层由TiN颗粒均匀分布的扩散层及表面TiN沉积层组成。将TiN渗镀层与Q235钢基体和1Cr18Ni9Ti不锈钢在4%的NaOH溶液、l mol/L H2SO4溶液和3.5%NaCl溶液中分别进行电化学腐蚀对比试验。结果表明:在4%的NaOH溶液中,TiN渗镀层的耐蚀性能比Q235钢提高了26.8倍,与1Cr18Ni9Ti不锈钢相当;在l mol/L H2 S04溶液中,TiN渗镀层耐腐蚀性能比Q235钢提高了10.5倍,比1Crl8Ni9Ti不锈钢提高了1.65倍;在3.5%的NaCl溶液中,TiN渗镀层耐腐蚀性能比Q235钢提高了10.3倍,但比1Crl8Ni9Ti不锈钢稍差。TiN渗镀层耐酸碱性溶液腐蚀性能要比耐盐溶液腐蚀性能强。     

AlFeCuCoNiCrTix高熵合金的组织结构及电化学性能

研究了不同Ti含量的AlFeCuCoNiCrTix多主元高熵合金的组织结构及其在0.5 mol/L的H2SO4溶液和1 mol/L的NaCl溶液中的电化学性能,并与304不锈钢进行了对比.结果表明,随着Ti元素的添加,合金的组织结构仍然主要由BCC相和FCC相组成.极化曲线结果表明,在0.5 mol/L的H2SO4溶液中的,与304不锈钢相比,该系合金具有较低的腐蚀速率;在1 mol/L的NaCl溶液中,该系合金的腐蚀速率与304不锈钢相当,但是其抗孔蚀的能力要优于304不锈钢.     

等离子铬镍共渗层与氮化钛薄膜的耐蚀性

对低碳钢表面进行等离子铬镍共渗,在4Cr13不锈钢表面沉积氮化钛薄膜.对两种强化层及其基体进行电化学腐蚀性能测试.结果表明:在1 mol/L的H2SO4溶液中,铬镍共渗试样的耐腐蚀程度和氮化钛薄膜的相当,是4Cr13不锈钢试样的90倍,是低碳钢试样的120倍;在1 mol/L的NaOH溶液中,铬镍共渗试样的耐腐蚀性是4Cr13不锈钢试样的0.67倍,是低碳钢试样4.67倍,是氮化钛薄膜的3.67倍;在3.5％的NaCl溶液中,铬镍共渗试样的耐腐蚀性是低碳钢试样的2.3倍,是氮化钛薄膜的0.167倍,是4Cr13不锈钢试样的0.33倍.     

AlFeCoNiCrTiV_x系高熵合金的组织结构及电化学性能

研究了不同钒含量的AlFeCoNiCrTi Vx(x为摩尔比,x=0.5,1,1.5,2)多主元高熵合金的组织结构及其在0.5 mol/L H2SO4溶液和1 mol/L NaCl溶液中的电化学性能,并与市售304不锈钢进行了对比。结果表明:随着钒元素的添加,合金的组织结构逐渐由两个bcc相组成变为单一的bcc相。极化曲线测试结果表明,在0.5 mol/LH2SO4溶液以及1 mol/L NaCl溶液中,该系合金的耐腐蚀性要明显优于市售304不锈钢,而其中AlFeCoNi-CrTi V0.5合金具有最优越的综合耐腐蚀性能。     

厚类金刚石碳基薄膜的制备及摩擦与腐蚀性能的表征

目的设计多层掺Si交替沉积的厚DLC薄膜,改善SUS304不锈钢的耐磨性与耐蚀性,拓展其使用范围。方法使用等离子增强化学气相沉积(PECVD)技术,在C_2H_2-SiH_4气氛中,通过Si_x-DLC与Si_y-DLC交替沉积的制备方法,以SUS304不锈钢为基底,制备了厚度为20.0、34.9、41.6μm的三种不同调制比(1∶5、1∶1、4∶1)的厚类金刚石碳基薄膜。利用扫描电子显微镜、原子力显微镜、拉曼光谱、纳米压痕仪、RST3划痕仪,分析了厚DLC薄膜的微观结构与力学性能。利用CSM摩擦磨损试验机评价厚DLC薄膜的摩擦学性能,并用能谱仪对磨斑成分进行分析。利用电化学工作站分析厚DLC薄膜的腐蚀行为,并用扫描电镜观察腐蚀形貌。结果厚DLC薄膜结构致密,强化效果明显,硬度最高达13.8GPa,结合力在21～29N范围内。SUS304不锈钢的摩擦系数在跑和阶段急速升高至0.5,随着滑动次数的增加,呈上升趋势,1 h后,磨损率无法用轮廓仪测量。厚DLC薄膜在低载荷与高载荷下的摩擦系数始终保持在0.05～0.2之间,磨损率低至9.4×10~(-17) mm~3/(N·m)。电化学测试表明,SUS304不锈钢的腐蚀电位为-0.49V,腐蚀电流密度为1.46×10~(-6) A/cm~2。与SUS304不锈钢相比,三种厚度的DLC薄膜腐蚀电位正移、极化电阻升高,腐蚀电流密度最大可降低3个数量级。结论厚DLC薄膜的应用可以有效降低摩擦磨损,腐蚀倾向相比于不锈钢明显降低,具有良好的耐腐蚀性。     

化学镀Ni-Fe-P和Ni-Fe-P-B合金的耐蚀性研究

利用失重法和电化学测试法,对比研究以铝合金为基体化学镀Ni-Fe-P和Ni-Fe-P-B合金的耐蚀性.结果表明:这两种镀层浸泡在3.5%NaCl和10%NaOH溶液中均比浸泡在0.1mol/L H2SO4和1mol/L HCl中有更好的耐蚀性.另外,在3.5%NaCl和10%NaOH溶液中,Ni-Fe-P-B镀层合金比Ni-Fe-P有更好的耐蚀性;但是在0.1mol/L H2SO4和1mol/L HCl溶液中,Ni-Fe-P镀层合金却比Ni-Fe-P-B有更好的耐蚀性;     

超音速火焰喷涂FeCrSiB涂层的腐蚀行为

采用超音速火焰(high velocity oxygen fuel,HVOF)喷涂技术在Q235钢基体上制备了FeCrSiB合金涂层.利用X射线衍射仪、扫描电子显微镜、电化学工作站等设备对涂层的显微组织结构和耐腐蚀性进行了研究.结果表明,采用HVOF喷涂技术制备的FeCrSiB涂层结构致密,孔隙率为0.65%,与基体结合良好.FeCrSiB涂层在3.5%NaCl溶液、1 mol/L HCl溶液和1 mol/L NaOH溶液中都经历了活性溶解-钝化-过钝化的过程,且该涂层在3.5%NaCl溶液和1 mol/L HCl溶液中的耐腐蚀性能要优于镀铬层,在1 mol/L NaOH溶液中的耐腐蚀性能低于镀铬层.     

不同掺杂对类金刚石薄膜的影响

目的研究单掺Si和共掺Ag、Si对类金刚石薄膜的结构、摩擦学性能和耐腐蚀性能的影响。方法以高纯石墨靶、石墨与金属复合靶、Si靶作为靶材,采用射频增强磁控溅射技术制备不同掺杂种类的薄膜。通过XPS、拉曼光谱仪对薄膜的化学组成和结构进行分析,通过纳米压痕仪、摩擦磨损试验机、电化学工作站等,对薄膜的力学性能、摩擦学性能及耐腐蚀性能进行了系统研究。结果 Si元素单掺DLC会引起薄膜中sp~3C含量增加。Ag、Si共掺DLC后,由于Ag以金属相分布在薄膜中,并促进sp~2相的形成,导致sp~3C含量降低。掺杂元素后的DLC薄膜,硬度下降,但韧性提高,其中Ag、Si共掺的DLC薄膜的弹性恢复系数达到79%。此外,Ag、Si共掺DLC薄膜在多种气氛(Ar、O_2、N_2)中都具有优异的摩擦学性能,磨损寿命均超过30 min,其中在N_2气中的摩擦系数最低(0.1),并在NaCl溶液中的腐蚀电流密度比304不锈钢基体降低了近2个数量级,具有良好的耐腐蚀性。结论 Si与Ag共掺DLC薄膜较Si单掺薄膜具有更好的摩擦环境适应性和耐腐蚀性能。     

304不锈钢在硝酸盐及硫酸溶液中的钝化

利用电化学方法和表面分析技术研究了304不锈钢在 硝酸盐及硫酸溶液中的钝化行为.结果表明，304不锈钢经硝酸盐及硫酸溶液中钝化后在3.5%NaCl溶液中的耐蚀性大为提高.SEM分析表明，经过H2SO4+KNO3钝化后，钝化膜具有网状的结构，膜层结合紧密；而单独在H2SO4溶液中钝化后，表面为有裂纹的钝化膜，微孔较多；单独在KNO3溶液中钝化，与未处理的基本相同.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.