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1.
隋曼龄  卢柯 《金属学报》1994,30(21):413-419
采用非晶晶化法制备出晶粒尺寸不同的Ni-P合金复相纳米晶体样品。利用X射线衍射技术分别对样品中Ni固溶体和Ni_3P的晶格参数随晶粒尺寸的变化进行了测试,发现在Ni固溶体纳米相中P的固溶浓度增大,约为平衡固溶度的10-15倍,形成超过饱和固溶晶格结构;在Ni_3P化合物纳米相中空位浓度增加导致晶格畸变发生,而且随晶粒尺寸减小晶格畸变程度增大。  相似文献   

2.
纳米晶体Ni-P合金晶粒微观结构的研究SCIEI   总被引:1,自引:0,他引:1  
隋曼龄  卢柯 《金属学报》1994,30(9):B413-B419
采用非晶晶化法制备出晶粒尺寸不同的Ni-P合金复相纳米晶体样品。利用X射线衍射技术分别对样品中Ni固溶体和Ni_3P的晶格参数随晶粒尺寸的变化进行了测试,发现在Ni固溶体纳米相中P的固溶浓度增大,约为平衡固溶度的10-15倍,形成超过饱和固溶晶格结构;在Ni_3P化合物纳米相中空位浓度增加导致晶格畸变发生,而且随晶粒尺寸减小晶格畸变程度增大。  相似文献   

3.
化学镀Ni—P—Al2O3工艺及性能研究   总被引:11,自引:0,他引:11  
研究了制取含Al2O3粒子量高且镀液稳定的Ni-P-Al2O3化学复合镀液的工艺方法;讨论了镀液组成和工艺对沉积速度的影响,并在此基础上进一步研究镀层的组织性能及机理,在Ni-P合金镀液中加入Al2O3粒子(3~5μm)形成复合镀层,且Al2O3与Ni-P合金基质机械结合,复合镀层保持Ni-P合金结构,复合镀层表现更优良的机械性能。  相似文献   

4.
成分和结构对Ni—W—P镀层抗冲刷腐蚀性能的影响   总被引:3,自引:3,他引:0  
研究了不同成分和结构的NiWP合金镀层的硬度、耐蚀性及在液固双相流中的抗冲刷腐蚀性能,并对镀层表面膜进行了XPS分析,结果表明:镀层中钨含量的增加有利于提高镀层的硬度、耐蚀性和抗冲刷腐蚀性能。由Ni(OH)2,WO3,Ni3(PO4)2组成的表面膜具有较强的修复能力,这是使镀层具有优异抗冲刷腐蚀性能的主要因素之一。400℃以下较低温度的热处理提高了镀层的硬度,但削弱了镀层的耐蚀性,然而对抗冲刷腐蚀性能却略有提高。  相似文献   

5.
Ni-La_2O_3复合镀层对Ni抗高温循环氧化性能的影响   总被引:2,自引:0,他引:2  
1273K循环氧化100h的实验结果表明,金属Ni表面沉积一层Ni-La_2O_3复合镀层(厚为30μm)后,抗循环氧化性能比金属Ni和表面沉积相同厚度Ni镀层的金属Ni有极大改善。Ni及其单镀Ni后,氧化速率快,氧化皮严重开裂;沉积复合镀层后,氧化速率显著降低,表面氧化层晶粒明显细化,氧化皮下发生开裂电子探针(EPMA)观测发现,La_2O_3分布在氧化层(50μm厚)的上表层(31μm厚)中。高分辨电子显微镜(HREM)发现复合镀层中分布着尺寸<5nm的La_2O_3纳米颗粒,据此提出,氧化时,由于小尺寸的La_2O_3纳米颗粒易部分溶解,成为产生并在氧化层晶界偏聚的La~(3+)的"储存池"。La~(3+)在NiO晶界偏聚,阻止了Ni~(2+)的短路扩散,改善了复合镀层氧化层的生长机制和力学性质.  相似文献   

6.
玻璃组分与Cu—Ni熔体过冷稳定性   总被引:2,自引:0,他引:2  
在高真空下,研究了50 % (79 % Si O2 + 12 .5 % B2 O3 + 2 .2 % Al2 O3 + 0 .6 % Ca O + 5 .7 % Na2 O) ( 简写为 Na Ca Al B Si) + 50 % ( Na2 B7 O4) 对 Cu50 Ni50 和 Cu70 Ni30 合金熔体循环过热过程中过冷度稳定性的影响。结果表明,50 %( Na Ca Al B Si) + 50 % ( Na2 B7 O4) 玻璃对合金熔体的净化过程为物理—化学复合净化, 且在( Na Ca Al B Si) 净化剂中加入( Na2 B7 O4) 玻璃形成的净化剂粘度适中,因此合金熔体在2 ~5 次循环过热过程中可以获得稳定深过冷。  相似文献   

7.
化学镀Ni-P合金中无机盐加速剂的影响   总被引:5,自引:1,他引:4  
研究了在化学镀NiP合金镀层时,采用无机盐复合加速剂降低镀液温度、提高沉积速度的方法。结果表明,在普通化学镀NiP合金镀液中添加无机盐复合加速剂HN3(3份(NH4)2SO4与2份K2CO3的混合物)30g/L,在80℃下施镀,其沉积速度可达15μm/h,比不含该加速剂时提高40%左右,镀液寿命可达5个周期以上,镀层外观光亮,结晶细致。  相似文献   

8.
一种高速化学镀Ni-Cu-P合金工艺   总被引:6,自引:0,他引:6  
开了一种高速化学镀Ni-Cu-P合金工艺,研究了镀液中CuSO1.5H2O浓度、pH值、温度对镀层成分、镀速的影响,并根据GB10124-88标准对镀层作了耐蚀性试验。结果表明,本工艺在各参数较大的变化范围内均可获得较高的镀速,最高镀速可达28um/h,而且镀层具有较好的耐蚀性,该工艺条件下获得的镀层在50%H2SO1(室温)和50%NaOH(95O)中的耐蚀性远高于1Cr18Ni9Ti、1Cr18Ni12Mo2Ti等不锈钢、碳钢以及Ni-P化学镀层。  相似文献   

9.
化学复合镀制备高活性节能NiCo2O4电极   总被引:1,自引:0,他引:1  
在贱金属铁基表面化学镀Ni-Co-P,然后通过化学复合镀制得Ni-Co-P-A12O3底层,复合镀层用NaOH溶液浸出,可制得新型Ni-Co-P微孔活性中间导参中间导地涂覆匹配性较好的NiCo2O4表面活性层,该表面活性层由一定浓度配比的Ni(NO3)2和Co(NO3)2通过高温热解而成。 射结果表明表面活性层是由NiCo2O4组成,不存在NiO和Co3O4的独立相。这种新型表面活性层用于碱性水电  相似文献   

10.
用金相、电子探针(EPMA)、透射电镜(TEM)及高分辨电子显微镜(HREM)对Ni-La2O3复合电镀层的表面形貌及LaO3质点在镀层中的存在情况进行了研究.发现随着镀液中La2O3颗粒含量增加,复合镀层中La2O3的弥散量增多,镀层晶粒细化.La2O3质点以两种组织状态均匀分布于镍层中:其一为纳米级晶体(绝大多数<50nm)的弥散状态;另一种为微米级(~1μm)的“聚合体”状态,是由更微小的纳米晶体(~10nm)所组成,由于Ni-La2O3复合镀层用作扩散渗铝制备La2O3氧化物改性的铝化物涂层的基底层,文中还就复合涂层的La2O3质点弥散与组态对改性的铝化物涂层的显微结构及其氧化行为的影响作了进一步探讨.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
吴玉梅  熊晓云  靳蓉  孙敬民  杨林  罗晓星 《金属学报》2005,10(10):1100-1103
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。  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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).  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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