共查询到16条相似文献,搜索用时 62 毫秒
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为提高AZ91镁合金的耐腐蚀性能,优选了AZ91镁合金表面直接化学镀镍工艺,并对镀镍层的致密性、硬度、耐蚀性及结合力等进行了测定。获得了最佳工艺条件:5g/LNi(CH3COO):,12mL/L40%HF,5g/Lc6H807·H20,30g/L25%NH3·H20,20g/LNa2HP04·H20,1mg/L硫脲,p... 相似文献
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硫酸镍和碱式碳酸镍主盐对镁合金化学镀镍的影响 总被引:3,自引:1,他引:3
为了比较镁合金化学镀镍中主盐性质的影响,分别采用硫酸镍(NiSO4·6H2O)和碱式碳酸镍[NiCO3·2Ni(OH)2·2H2O]为主盐对AZ91D镁合金进行化学镀镍.采用扫描电镜(SEM)比较了镀层的表面形貌和组织结构,用能谱(EDS)对2种主盐所得镀层进行成分分析,采用中性盐雾试验比较了不同主盐化学镀镍后镀层的耐腐蚀性,并通过热震和锉刀试验比较两者的结合力,最后在3.5%NaCl溶液中进行动电位极化曲线测试.结果表明,碱式碳酸镍作为镁合金化学镀主盐所得的镀层为高磷镀层,且致密性、耐腐蚀性和结合力均好于硫酸镍作为主盐的镀液. 相似文献
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Weimin MAO Aimei YIN Xueyou ZHONG Foundry Institute School of Materials Science Engineering University of Science Technology Beijing Beijing China 《材料科学技术学报》2005,21(4):505-509
The compression tests of semi-solid AZ91D Mg alloy have been conducted on a parallel-plate viscometer. The results are as follows. With increasing the compression temperature, the deformation rate or the strain rate of the specimens rises, but the compressive stress continuously decreases; the deformation strain is obviously linear with the compressive stress and independent on compression temperature under a given compression load. In the wake of the compression load being added, the compressive strain increases but the compressive stress decreases clearly; the deformation strain is obviously linear with the compressive stress under different compression load. The mathematical apparent viscosity model about the semi-solid compressed AZ91D Mg alloy has been established, i.e. ηapp=2004.2exp(15.61fs)γ1.317fs-1.3511. 相似文献
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AZ91D镁合金表面熔盐置换扩散涂层组织及耐腐蚀性能研究 总被引:1,自引:0,他引:1
采用AlCl3-NaCl熔盐自发置换扩散工艺在AZ91D镁合金表面制备镁铝金属间化合物涂层,并利用开路电位、电化学阻抗方法对镁合金及熔盐置换扩散改性处理试样在3.5%(质量分数)NaCl溶液中的腐蚀行为进行比较研究。结果表明:熔盐自发置换扩散铝涂层在温度为400℃,保温8h的工艺条件下呈现出了明显的分层结构特征。根据组织结构不同,可将其分为:颗粒状形貌的外层和具有网状结构的内层;经表面熔盐自发置换扩散处理后的镁合金试样,腐蚀电位比未改性的AZ91D镁合金大幅提高,膜层阻抗约为未改性的AZ91D镁合金的10倍。 相似文献
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Bonian HU Gang YU Jueling CHEN Ying LI Liyuan YE College of Chemistry Chemical Engineering Hunan University Changsha China Hunan College of Building Materials Hengyang China 《材料科学技术学报》2005,21(3):301-306
In this research we presented a non-cyanide plating process of Ni-P alloy coating on Mg alloy AZ91D. By applying a new process flow of electroless nickel plating in which zinc coating is used as transition of Ni-P coating on Mg alloy AZ91D, the process of copper transition coating plated in the cyanides bath can be replaced. A new bath composed of NiSO4 was established by orthogonal test. The results show that zinc transition coating can increase the adhesion and pH 4.0 and 95℃, respectively. The present process flow is composed of ultrasonic cleaning→alkaline cleaning→acid pickling→activation→double immersing zinc→electroplating zinc→electroless nickel plating→passivation treatment.The present non-cyanide process of electroless nickel plating is harmless to our surroundings and Ni-P coating on Mg alloy AZ91D produced by present process possesses good adhesion and corrosion resistance. 相似文献
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The corrosion of magnesium alloy in different plating solutions was researched. The results demonstrated that corrosive condition of the alloy immersed in nickel chloride solution and nickel sulfate solution is serious and in nickel acetate solution and nickel nitrate solution is less. Magnesium alloy was handled with four acid pickling formulas and two activation formulas and the effects of different pickling formulas and activation formulas were researched through comparative experiment. The experimental results indicated that after handed with pickling formula about 500 mL L?1 H3PO4 (85%), 110 mL L?1 HNO3 (68%), room temperature for 30 s and activation formula about 375 mL L?1 HF (40%), room temperature for 10 min, magnesium alloy could realize electroless nickel plating directly and the performance of the prepared plating was much better. The properties of the nickel-plating coating were researched by electrochemical workstation, scanning electron microscope, and X-ray diffraction. The results demonstrated that this Ni–P coating was very uniform and meticulous; the structure of Ni–P coating was amorphous; and comparing with magnesium alloy, the corrosion potential of this plating increased about 799 V and the corrosion current density declined obviously. The nickel-plating coating effectively improved the anticorrosion performance of magnesium alloy. 相似文献