模具钢表面阵列微结构蚀刻工艺的实验研究

通过喷淋蚀刻实验研究了模具钢微细蚀刻加工时,工件掩膜间隙、蚀刻液喷淋压力和加工时间对蚀刻深度的影响。蚀刻深度随掩膜间隙的蚀刻尺寸、加工时间的增加而增大,随蚀刻液喷淋压力的增大呈先增大后减小趋势。这归因于掩膜间隙和蚀刻液喷淋压力的增大加快了蚀刻液的更新,使蚀刻反应充分并有利于反应杂质的排除。但是过大的喷淋压力减小了蚀刻液驻留时间,阻碍了蚀刻深度的增加。     

模具钢喷淋微细蚀刻的侧蚀研究

对掩膜处理的模具钢进行喷淋微细蚀刻,观测表面微观结构,分析掩膜间隙尺寸、喷淋压力对侧蚀量的影响。实验表明,随着掩膜间隙尺寸的增大,侧蚀量增大,这是因为微结构凹坑内部蚀刻液的滞留和对O2阻碍作用,造成了不同部位蚀刻速率不同,发生侧蚀;喷淋压力增大也导致侧蚀量增加,因为较大压力下蚀刻液的侧向蚀除力大,侧向蚀除作用强,同时蚀刻液更新频率快,反应速率提高,侧蚀增大。在微细蚀刻加工中合理地选择掩膜间隙尺寸,控制加工时间和喷淋压力,可以较好地控制侧蚀,保证较高的加工尺寸精度。     

喷淋蚀刻模具钢的蚀刻深度研究

采用喷淋式蚀刻机,以FeCl3基蚀刻液对模具钢进行喷淋蚀刻,通过测定不同蚀刻液温度、不同喷淋压力下的蚀刻深度,考察了几个独立因素对蚀刻深度的影响,得出蚀刻深度的规律性变化:蚀刻深度增长速率随蚀刻液温度的升高而增大,随喷淋压力的增大而先增大,后逐渐减小。分析了蚀刻深度呈此种变化规律的原因。     

模具钢微细蚀刻的侧蚀研究及其工艺优化

目的 研究 HNO₃ 浓度、喷淋压力、掩膜间隙、加工时间对侧蚀量的影响规律。 方法 设计正交实验,测定蚀刻后的侧蚀量,采用极差分析、方差分析法对侧蚀量进行分析,通过验证性实验进行验证。结果 侧蚀量随加工时间的延长以及喷淋压力、加工时间的增大而增大, 随 HNO₃ 浓度的增大而减小。侧蚀量最小的工艺是:HNO₃ 浓度为 1 . 8 mol / L,喷淋压力为 0 . 2 MPa,掩膜间隙为 50 μm,蚀刻时间为 2min。 结论 加工时间对侧蚀量有显著性影响,喷淋压力对侧蚀量影响较大,其次是掩膜间隙和 HNO₃ 浓度。 验证性试验证明最优工艺方案可行。     

模具钢大面积微结构的微细电解和化学蚀刻的比较研究

针对手机后盖表面微结构的特点,采用微细电解和微细蚀刻的方法,对手机后盖压制模具的表面微结构加工进行工艺探索。设计了掩膜图形,研制了微细电解加工的纳秒脉冲电源。利用自行研制的多功能微细特种加工系统,采用阳极掩膜的方法进行微细电解加工,采用改进后的蚀刻机进行模具钢微细蚀刻加工。通过优化工艺,在模具钢材料上加工出尺寸为500μm的阵列微结构,并注塑出手机后盖,达到项目要求。     

单晶硅化学蚀刻行为的研究

用HF+HNO.3溶液蚀刻单晶硅表面,通过扫描电镜表征其形貌和厚度变化,研究了蚀刻液浓度、蚀刻时间及温度对单晶硅化学蚀刻行为的影响.结果表明,温度对蚀刻速率的影响较大,温度升高使表面蚀刻不均匀,厚度急剧减小;硅片的厚度及表面形貌在蚀刻液浓度大于2.0 mol/L时变化较显著;室温时用1.5 mol/L HF+HNO3蚀刻15 min获得了蚀坑大小适中(10 μm～15 μm)、分布均匀的多孔状表面.     

三氯化铁溶液中影响铁镍合金蚀刻速率的因素

采用浸渍蚀刻的方法,研究了影响Fex(x=56～59)Ni1-x合金箔在三氯化铁溶液中蚀刻速率的几个因素,并对蚀刻液的有效蚀刻能力及失效蚀刻液的除镍和再生进行了初步的研究.研究结果表明:氧化还原电位随蚀刻液浓度的增大而升高,氧化还原电位越高,蚀刻反应趋势越大;蚀刻速率随浓度的增加先增大,再下降,且在浓度为40%左右出现极大值;蚀刻液温度越高、pH值越小,蚀刻速率越大;除镍后的失效蚀刻液经再生后能达到新鲜蚀刻液的90%以上,基本达到再生利用的要求.     

膜电解法再生FeCl3蚀刻液的蚀刻性能研究

对某蚀刻厂的废蚀刻液通过膜电解工艺进行再生,并通过蚀刻性能条件实验研究了蚀刻时间、温度、蚀刻液浓度、蚀刻液游离酸含量等因素对蚀刻液 (新蚀刻液、在线蚀刻液、再生蚀刻液) 氧化还原电位和蚀刻速率的影响。结果表明,再生蚀刻液满足蚀刻要求,并且当蚀刻温度为50~60 ℃、蚀刻液浓度为再生蚀刻液浓度的90%、游离酸浓度为0.3 mol/L以上时,再生蚀刻液蚀刻速率最大。     

硝酸型酸性蚀刻液蚀刻工艺的研究

研究了以硝酸为主成分的酸性蚀刻液。采用静态蚀刻的实验方法,通过测定蚀刻液对印制电路板铜箔的蚀刻速率和侧蚀量,考察了几个独立因素的影响。结合正交实验得出硝酸型酸性蚀刻液的最佳组分及工艺条件为：Cu2＋质量浓度为（140±10）g/L,硝酸浓度为（2.5±0.5）mol/L,温度为（50±5）℃。在该条件下,静态蚀刻速率可达到10μm/min,且侧蚀量小。此外,还考察了抑烟剂对蚀刻速率的影响。     

一种新型单过硫酸氢钾/ 磷酸微蚀体系在PCB 微蚀中的应用

介绍了一种新型微蚀刻体系,其组分主要包括单过硫酸氢钾复合物、磷酸及稳定剂等,研究了温度、组分用量、铜含量等因素对蚀刻的影响。结果表明:温度对该蚀刻体系的影响较大,以37 ~43 ℃范围为宜;磷酸在稳定剂的存在下可维持槽液pH 值稳定,提高处理效果,其用量为1. 6% ~2% 时有利于蚀刻;单过硫酸氢钾复合物在50 ~100 g/ L 为宜,通过控制其用量可获得所需的蚀刻量;铜含量对蚀刻速率影响较大,当铜含量上升时,需不断添加微蚀液以维持一定蚀刻量。与传统蚀刻体系相比,该微蚀刻体系具有蚀刻量低、更容易控制、药液更稳定等特点,能更好地满足PCB 蚀刻的要求。     

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.     

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.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。