化学复合镀镍-磷-金刚石镀速的研究

研究了在化学校镍磷合金镀液中加入金刚石微粒形成镍-磷-金刚石复合镀层的共沉积过程，分析镀液中各成分及操作条件对合金镀层沉积速度的影响，并对镀层的组织和性能进行了测试，结果表明：Ni—P—金刚石复合镀层镀速可达28μm/h，硬度可达HV0.11850左右。     

微米金刚石在化学复合镀中的合成与性能

在磨料磨具行业中,超硬材料金刚石的应用一直是行业研究、关注的问题。本文结合化学复合镀,扩展金刚石的应用,将微米金刚石与Ni—P镀液化学复合,探讨了复合镀层的沉积机理,以及微米金刚石对复合镀层硬度和耐磨性的影响。结果表明：加入的金刚石颗粒均匀地分布于Ni—P基体中,可以使镀层晶粒细化,起弥散强化作用,从而极大提高复合镀层的耐磨性,但对硬度的影响较小。改变金刚石的加入量对镀速的影响很小;随镀液金刚石加入量的增加,镀层金刚石含量先是迅速增加,以后增加趋势越来越缓慢,达到顶点后开始下降;镀层对金刚石微粒的俘获能力是有限的,颗粒的吸附主要是依靠机械力的作用。     

不同前处理对复合镀层与基体的结合力影响研究

为探究具有优良性能的复合镀层的金刚石处理工艺,对金刚石微粒进行不同的前期处理,以不同前处理方式的金刚石微粒为研究对象,运用化学复合镀的方法,在铜基体的表面制备镍-磷-金刚石复合镀层。分别利用自动划痕仪测试镀层的结合力并进行讨论分析。结果表明:王水、硝酸处理的粒子镀层结合力最强。综合来看,对金刚石微粒进行合理的前期处理能有效提高镀层的结合力。     

镍-磷-金刚石超微粉化学复合镀的耐磨性研究

研究了化学复合镀Ni-P-金刚石镀层的耐磨性。通过观测热处理前后的金相组织、硬度变化,对比了热处理前后镀层的耐磨性。结果表明:采用合适的工艺条件,可获得金刚石微粉分布均匀的镀层,经热处理后,镀层硬度可达901 HV0.2,且镀层与基体结合力良好,耐磨性大大提高。     

Ni-P-金刚石化学复合镀层的组织结构及性能

研究了Ni-P-金刚石复合镀层的组织结构及性能特点，结果表明：复合镀层镀态时为非晶结构；镀层经300℃，1h的热处理后开始晶化，晶化后形成品相Ni和Ni3P；与Ni—P镀层相比，Ni-P-金刚石复合镀层具有更好的硬度和耐磨性，特别是在镀态时差别更明显；但复合镀层的耐蚀性和抗氧化能力低于普通Ni-P镀层。     

磁场下化学复合镀镍-磷-金刚石镀层性能的研究

为了提高复合镀层的耐磨性、改善复合镀层的结合力、硬度,在不同的磁场强度和不同的金刚石添加量下进行了化学复合镀,于铜基体表面制备了一层镍-磷-金刚石复合镀层,然后对镀层性能进行表征。结果表明,金刚石粒子含量为2g/L^4g/L时,随着磁场强度的增大,镀层的厚度逐渐增大,而当金刚石粒子含量增加到6g/L时,镀层的厚度逐渐减小;金刚石含量4g/L时,镀层摩擦系数随磁场增大而降低;结合力在各金刚石含量下随磁场的增大先略微减小后大幅增加;各金刚石含量下镀层硬度随磁场的增大先增大后减小,磁场强度2.6m T、金刚石粒子含量为4g/L时最大。     

Ni-P金刚石化学复合镀层制备及摩擦磨损性能分析

目的研究不同粒径微米金刚石对Ni-P金刚石化学复合镀层摩擦磨损性能的影响。方法选择出一组优良的Ni-P化学镀工艺参数,在镀液中分别加入不同粒径的金刚石微粒,制备含不同粒径微米级金刚石颗粒的化学复合镀层。用SEM和XRD,观察并分析了不同粒径金刚石对热处理前后Ni-P金刚石化学复合镀层微观形貌和组织结构的影响;通过硬度和摩擦磨损实验,研究了不同粒径金刚石颗粒对复合镀层硬度及摩擦磨损性能的影响。结果制备的复合镀层厚度为30μm左右,金刚石质量分数达到21%~25%,且金刚石均匀分散在Ni-P镀层中。热处理前镀层为非晶结构,经过400℃×2 h的热处理后,镀层晶化为硬度更高的Ni3P。金刚石能提高镀层硬度,其中粒径为9μm的复合镀层硬度最高,达到1261HV。Ni-P金刚石复合镀层的摩擦系数为0.4~0.52,随着金刚石粒径的增大,摩擦系数不断减小。金刚石使镀层的磨损机制发生了变化,随着金刚石粒径的增大,硬质合金球的磨损加剧。结论随着金刚石粒径的增大,镀层硬度增加,摩擦系数减小,耐磨性增大。     

Ni-Co-Mn合金的电镀工艺优化及与金刚石复合镀的摩擦磨损性能

通过电镀法制备Ni-Co-Mn三元合金并进行工艺优化,同时制备Ni-Co-Mn-金刚石复合镀层,采用硬度、纳米划痕、SEM、EDS、摩擦磨损等分析镀层性能。结果表明:Ni-Co-Mn三元合金电镀最佳主盐配方为Ni SO4 280g/L、Co SO4 11 g/L、Mn SO4 1 g/L;镀液温度低于50℃时镀层易"烧焦",高于60℃时,镀层硬度及结合力下降;当电流密度增大至3 A/dm2时,有利于形成平整致密的镀层;当电流密度超过5 A/dm2时,镀层表面易出现析氢、积瘤等缺陷;最佳电镀工艺条件下的镀层硬度达520.7 HV,膜基结合力达25.52 N;Mn含量越高,镀层硬度越大;Co含量越高,镀层与基体结合越好;Ni-Co-Mn-金刚石复合镀层的硬度达890.2 HV,摩擦因数为0.72,体积磨损率仅为5.46×10-6 mm3/(N·m),金刚石与胎体Ni-Co-Mn合金结合牢固,复合镀层的磨削性好,耐磨性强。     

含纳米金刚石粉镍钴基复合镀层的研究

通过对爆轰制备的纳米金刚石粉进行去除杂质，亲水处理，制备出分散稳定的含纳米金刚石粉的镀液。利用这个镀液制备出含纳米金刚石粉的Ni—Co复合电镀层，并研究了镀液中分散不同含量纳米金刚石粉对制备镀层的表面形貌，晶粒尺寸的影响，镀液中纳米金刚石粉含量从2g／L增加到6g／L，镀层的晶粒尺寸减小近一半。纳米金刚石粉对晶粒的细化程度和镀层中含有的纳米金刚石粉的含量有很大关系。镀层的显微硬度与镀液中分散的纳米金刚石粉的含量并不成线性关系，镀层的显微硬度最大可达601．53HV。团聚的纳米金刚石粉导致镀层晶粒的异常长大。     

Ni-P-金刚石粉化学复合镀层的性能

本文用扫描电镜对Ni－P－金刚石粉化学复合镀层的表面状态及内部形貌进行了观察，并用图像处理仪定量计算了复合镀层中金刚石粉的体积百分数。结果表明，随镀液中金刚石粉添加量增加，镀层中金刚石粉含量也增加；金刚石粉在镀层中呈均匀分布。同时，测定了复合镀层的力学性能，结果指出，复合镀层中金刚石粉含量增加，硬度、耐磨性提高。     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.     

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.     

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.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.