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本文报道了Ni-P非晶在不同退火温度下磷的表面偏析和脆化行为及二者之间的关系。发现近表面区在退火过程中形成一个贫磷层,其厚度随温度增加,磷的贫化程度随退火温度加剧。本文从非晶中原子扩散激活能可变化的观点出发,对弛豫过程中元素再分布和脆化机制进行了讨论。 相似文献
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采用化学镀方法在AZ91D压铸镁合金表面获得N i-P镀层,研究了不同热处理温度对镀层的组织和性能的影响。结果表明:镍层中P含量为6.22 wt%,镀层组织为非晶+少量纳米晶组织。随热处理温度升高原始镀层中的非晶组织中先形成镍纳米晶,然后纳米晶镍伴随晶化过程进行迅速长大,并在镍基体上析出N i12P5和N i3P相。镀层与基体的结合强度在350℃附近达最大结合强度为3.7 MPa,镀层硬度在400℃附近达最大值为825 HV;盐雾腐蚀实验表明镀层耐腐蚀性能良好,连续盐雾8 h未出现腐蚀斑点。经过不同的热处理,镀层的耐蚀性随着热处理温度的提高而下降。 相似文献
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The structure and thermal stability of Ni100-xPxfilms (8<x<14.5) under isothermal annealing have been studied by X-ray and DTA methods. Equilibrium Ni and Ni3P phases have been found to be the final breakdown products on crystallisation of amorphous Ni-P films. The start of the crystallisation process for the concentration range studied has been shown to be shifted towards a higher temperature region with increasing phosphorus concentration. Non-equilibrium conditions of crystallisation using pulsed electrodeposition have been shown to have an essential effect on the processes of structure relaxation. 相似文献
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1.IntroductionTheiron-basedamorphousalloysproducedviarapidquenchingtechniquepossessgoodmechanicalproperties.However,toacquiredesirablesoftmagneticproperties,alongperiodofconventionalfurnaceannealing(CFA)(1-2h)isrequired.Unfortunately,theannealingembrittlementoccursinevitablytocreatemanydifficultiesinpractice.Flashannealingorelectricpulserapidannealing(EPRA)isbasedonthejouleheatingeffectsofatransientcurrentpulseflowinginanamorphousribbon.RecentlyithasbeenprovedthatEPRAisasuitablemethodfori… 相似文献
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本文系统地研究了随着磷含量的改变,电刷镀镍磷合金镀态的表面,平截面和纵截面的金相形貌。并测定了加热温度对不同磷含量的非晶镍磷合金的组织结构和硬度的变化规律。 相似文献
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The experimental researches on the chemical deposition of Ni-Mo-P amorphous alloys were carried out by adding Na2 MoO4 into acidic solutions. The optimum technology conditions were obtained by orthogonal design experiments. The structures and the relationship between compositions and their thermal stability were studied by energy spectrum (EC), scanning electron micrograph and X-ray diffraction spectrum. Compared with Ni-P amorphous alloys, the Ni-Mo-P amorphous alloys have high crystallization temperature and thermal stability, and the hardness reaches its peak when the annealing temperature is 500 ℃. With the increase of the heat treatment temperature, the surface morphology of the alloys changes. 相似文献
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Xuetao Yuan Dongbai Sun Hongying Yu Huimin Meng Zishuan Fan Xudong Wang 《Surface & coatings technology》2007,202(2):294-300
Amorphous-nanocrystalline composite structured Ni-P deposits (with phosphorus content of 5-9 wt.%) show better corrosion resistance than that of microcrystalline structured Ni-P deposits, and better abrasion resistance than that of amorphous Ni-P deposits. In order to get amorphous-nanocrystalline composite structured Ni-P deposits on AISI 431 stainless steel, electroplating parameters that affect phosphorus content in Ni-P deposits (temperature, current density, pH, H3PO3 concentration and agitation rate) are analysed by orthogonal experimental design (OED) in this paper. The analysis indicates that pH value and phosphorous acid concentration are key variables, their interactive effect on Ni-P composition should be taken into account. The effects of pH and H3PO3 concentration of the electroplating bath on phosphorus content in Ni-P deposits are further examined by the method of steepest ascent and central composition design (CCD). On the basis of results and discussion in experimental design sections, various Ni-P deposits with approx. 5-9 wt.% phosphorus can be galvanostatically electroplated by controlling the key variables and these deposits are confirmed to be amorphous-nanocrystalline composite structure in XRD, TEM tests. 相似文献
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研究了黄铜化学镀镍磷合金的工艺。对镀层的成分、结构、结合力和耐腐蚀性进行了分析研究。实验表明:采用酸性镀液施镀,可得到结合力强,磷含量大于12%,非晶态结构的Ni-P合金镀层;并具有优异的耐蚀性。 相似文献
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采用化学沉积方法获得了Ni-P纳米晶和非晶两种镀层,对镀态镀层进行低温去应力退火处理。分析了镀层成分和结构,研究了组织结构和退火工艺对镀层摩擦学性能的影响规律及其内在机制。结果表明:Ni-P纳米晶镀层的摩擦学性能明显优于同条件下(仅改变镀液中的络合剂)制备的非晶镀层,镀层磨损机制发生了变化;适当地去应力退火有助于进一步提高镀层的显微硬度,达到降磨减摩的效果。 相似文献
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Xiao Lyu Donggang Li Qiang Wang Kai Wang Changsheng Lou Jicheng He 《Journal of Materials Engineering and Performance》2013,22(10):3134-3139
The influence of static magnetic field of 4 T on electroless Ni-P deposition process and post-annealing was investigated in this study. The results from differential scanning calorimeter have shown that the imposed high magnetic field during electroless deposition had a further beneficial effect on defects migration and annihilation after Ni-P alloys heated at around 250 °C. Furthermore, it is found that some metastable phases were presented after magnetic annealing at 300 °C (below crystallization temperature), and the hardness of magnetic-annealed Ni-P alloys was greater than that of conventionally annealed Ni-P alloys. The morphology of the Ni-P alloys was characterized by scanning electron microscope, and shows typical spherical nodular structure for the as-deposited Ni-P alloys. The boundaries of these spherical nodular crystals blurred after annealing; however, the boundaries were apparently observed after magnetic annealing at 300 °C. 相似文献
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《Surface & coatings technology》1987,31(1):31-43
Electrodeposited amorphous Ni-P alloys were produced in an electrolyzing tank by using plane-parallel electrodes which did not fill the whole tank wall area. The resulting non-uniform current density distribution over the cathode area caused a lateral variation in the thickness and the phosphorus content and both parameters were measured locally on the deposits. The conditions for obtaining uniform electrodeposited amorphous Ni-P alloys and the dependence of deposit composition and cathode current efficiency on the local current density were established in detail. It was also found that during the deposition of usual foil thickness (10 - 100 μm) no bath deterioration occured. 相似文献
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The coatings with different phosphorus contents were obtained by varying the ratio of lactic acid to acetic acid in the electroless plating bath. With the increase of phosphorus content, the structure of the electroless Ni-P coating transformed from nanocrystalline to a mixture of nanocrystalline and amorphous phases, then to amorphous phase. A record high hardness value of 910 HV0.1 of as-deposited Ni-P coating was obtained at 7.97 at.% phosphorus content, and high wear resistance was accordingly achieved. The refined nanocrystalline grains with an average size of ~ 4 nm were found to be responsible for the record high hardness and improved wear resistance of the as-deposited Ni-P coating. 相似文献
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钨铜合金表面化学镀Ni-P镀层性能研究 总被引:2,自引:0,他引:2
从钨铜合金表面化学镀Ni-P镀层的表面形貌及成分,镀层结构,外观,结合力.硬度,耐磨性,孔隙率,纤焊性等方面进行了检测和表征.结果表明,化学镀Ni-P合金层磷含量为11.37%,属于高磷镀层,主要为非晶型结构,在钨铜合金表面化学镀Ni-P合金可以大大提高钨铜合金的硬度和耐磨性,且Ni-P合金镀层与钨铜合金基体结合强度好,孔隙率低,纤焊性好. 相似文献
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The optimum fluences for homogeneous amorphous phase production were determined in Part I of this work for accelerating potentials of 50, 100, 150, 175 and 200 kV. Polarization measurements of these amorphous specimens in room temperature 1.0 N H2SO4 at a scan rate of 0.1 mV s−1 in the present work show a decrease in the critical anodic and passive current densities by factors between 2 and 10 when compared to corresponding values for unimplanted, electropolished specimens. These decreases become less pronounced with increasing implantation energy. The presence of crystalline phases, especially b.c.c. phase, within the surface region of the amorphous phase degrades the observed amorphous phase improvements. Recrystallization of the amorphous structure removes all corrosion resistance improvements obtained from the P+ implantation. As discussed herein, the cause of the electrochemical improvements is a combination of a microstructural effect imparted by the amorphous phase and a chemical effect derived from the implanted phosphorus when present in quantities of 40% within 25 Å of the surface. Chromium depletion at the specimen surface during implantation, as well as during annealing, also degrades the electrochemical properties and acts in competition with improvements caused by the added phosphorus. 相似文献
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LU Ke WANG Jingtang National Laboratory of RSA Institute of Metal Research Academia Sinica Shenyang China LU Ke Associate Professor Institute of Metal Research Academia Sinica Shenyang China 《金属学报(英文版)》1992,5(7):33-37
A mathematical expression of the crystal growth rate during crystallization of the amorphousalloys was derived from the micromechanism of crystallization newly developed by theauthors. Thus, the satisfactory explanation of the experimental results obtained by Nunogakiet al., Heimendahl et al. and the authors might be found. It seems also to be modelled with theexpression for the crystal growth and the crystal size influenced by time during thecrystallization of amorphous Ni-P alloy foil at in situ heating. Based on the expression, thefactors influencing the crystal growth rate, such as temperature, time and microstructure ofamorphous alloys have been discussed. 相似文献