剪切带修复对Pd基块体非晶合金腐蚀性能的影响

摘 要：本文以Pd79Cu4Au2Si10P5块体非晶合金为研究对象,采用电化学极化曲线和电化学阻抗测试方法研究了剪切带自修复对其在3 wt.% NaCl溶液和1 mol/L HCl溶液中耐蚀性能的影响。通过研究极化曲线中的自腐蚀电位和自腐蚀电流密度得知,修复后样品耐腐蚀性能优于修复前样品,但仍低于原始样品（即未变形样品）。电化学阻抗研究结果显示,在开路电位下阻抗图均有单一容抗弧构成,修复后样品的电化学转移电阻Rt小于原始样品的、但大于修复前样品的,这进一步表明修复提高了材料的耐腐蚀性能,但仍未达到原始样品的耐蚀性。扫描电镜研究发现,合金表面发生明显的点蚀,其中原始样品的点蚀坑密度最少,修复后样品的次之,修复前样品的最多。     

Zr基非晶合金的热稳定性及耐腐蚀性能研究

通过铜模铸造法制备出了具有异质结构的Zr63Ni16.2Cu15.8Al5和Zr63.4Ni16.2Cu15.4Al5块体非晶合金.利用X射线衍射(XRD)和差示扫描量热法(DSC)研究了两种Zr基块体非晶合金的微观结构和热稳定性,采用动电位极化方法研究了两种Zr基块体非晶合金在NaCl水溶液中的耐腐蚀性能.结果表明,与均匀结构的Zr65Al10Ni10Cu15块体非晶合金相比,异质结构降低了材料的热稳定性以及耐腐蚀性能,耐腐蚀性能低的原因可能是由于微观结构的不均匀使其具有更多的界面引起的.     

Microstructure and Wear Resistance of Fe-Based Amorphous Metallic Coatings Prepared by HVOF Thermal Spraying

Amorphous metallic coatings with a composition of Fe₄₈Cr₁₅Mo₁₄C₁₅B₆Y₂ were fabricated by means of high velocity oxygen fuel (HVOF) thermal spraying process. The microstructure and wear performance of the coatings were characterized simultaneously in this article. It is found that the coatings present a dense layered structure with the porosity below 1.5%. The coatings primarily consist of amorphous matrix and some precipitated nanocrystals, though a fraction of Fe-rich phases and oxide stringers also formed during deposited process. High thermal stability enables the amorphous coatings to work below 920 K temperature without crystallization. Depending on the structural advantage, the amorphous coatings exhibit high average microhardness of 997.3 HV_0.2, and excellent wear resistance during dry frictional wear process. The dominant wear mechanism of amorphous coating under this condition is fatigue wear, leading to partial or entire flaking off of the lamellae. In addition, the appearance of oxidative wear accelerates the failure of fatigue wear.     

SiC对Ni-W合金耐蚀耐磨性能的强化作用

为提高严苛海洋环境下金属机件的服役性能,本文通过电沉积方法制备了Ni-W和Ni-W/SiC复合镀层。利用扫描电子显微镜（SEM）、能谱分析（EDS）和X射线衍射（XRD）等技术研究了SiC对Ni-W合金微观结构和性能的影响,采用电化学方法研究了复合镀层在3.5% NaCl溶液中的耐蚀性能,以探讨其海水综合防护性能。研究表明,经表面处理的SiC可诱导形核促进晶体生长,使Ni-W合金晶粒变细,镀层完整致密。SiC纳米颗粒均匀分布在Ni-W/SiC中,可有效提高镀层硬度及耐磨性,同时Ni-W/SiC也具有比Ni-W合金更好的耐蚀性能,在多因素交互作用的海洋环境中将具有更长的防护寿命,具有良好的应用前景     

Y对Cu基非晶合金形成能力和腐蚀行为的影响

采用铜模吸铸法制备出成分为(Cu50Zr45Al5)100-xYx(x=0,1,2,3,4,5)的合金试样。利用X射线衍射,金相显微镜,差热分析和电化学极化曲线的方法研究了Y对Cu-Zr-Al系非晶合金的结构、玻璃形成能力和腐蚀行为的影响。结果表明,适量Y的添加提高了非晶合金的玻璃形成能力和热稳定性,当Y含量为2%时合金的过冷液相区宽度为ΔTx=Tx-Tg=64K,约化玻璃转变温度Trg=Tg/T1=0.601,玻璃形成能力γ=Tx/(Tg+T1)=0.409(Tg,Tx,T1分别为非晶合金的玻璃转变温度,晶化开始温度和熔化温度)。非晶合金在3.5%的NaCl溶液中的耐蚀性随Y含量的增加而降低。     

铁基非晶及纳米晶合金在NaOH溶液中的耐蚀性比较

冶炼制备了纳米晶Fe73.5Si13.5B9Nb3Cu1和非晶带材Fe78Si13B9。在电化学工作站上测试了两种合金在不同浓度的NaOH碱溶液里的极化曲线。随着NaOH溶液浓度的不同,非晶Fe78Si13B9和纳米晶Fe73.5Si13.5B9Nb3Cu1合金极化曲线具有相似的变化规律,且纳米晶合金比非晶合金的腐蚀电位要高,耐腐蚀性要好。     

金属玻璃Pd－Cu－Si的耐磨特性

用Ｘ－射线衍射研究Ｐｄ－Ｃｕ－Ｓｉ合金玻璃丝和Ｎｉ－Ｐ非晶态镀膜摩擦付的结构，及其滑动磨损特性，表明负荷对磨损影响很大，磨损试验中，硬度没有增加。还探讨了磨损机制。     

Structure of Amorphous Metallic Alloys and the Conditions of Amorphization

The results of x-ray study of amorphous metal alloys are compared with the structural parameters of intermediate phases determined for equilibrium state diagrams and primary products of crystallization upon warming of amorphous alloys and crystal phases (formed at subcritical cooling rates) of the alloys susceptible to amorphization. It is found that susceptibility of the alloys to amorphization depends on the specific chemical interaction of the components which is revealed in the formation of the intermediate crystal phases. This conclusion is proved by the results of studying solid-phase reaction of amorphization.     

Effect of Sub-T_g Annealing on the Corrosion Resistance of the Cu–Zr Amorphous Alloys

Despite the economy of material cost and excellent toughness of Cu-based amorphous alloys, especially Cu_(50)Zr_(50), their poor corrosion resistance to a chloride medium limits their widespread applications. In this study, corrosion tests were performed on the Cu_(50)Zr_(50) amorphous alloy with different degrees of short-range order, which were prepared by annealing below the glass transition temperature(T_g). It was found that the corrosion resistance of amorphous alloys is improved to a significant level when the alloys were heated below T_g. Calorimetric studies showed that thermally activated relaxation process of created disorder, which occurs during sub-T_gannealing, is responsible for the improvement in the corrosion resistance. Molecular dynamics simulations performed on the Cu–Zr amorphous alloys demonstrated that the relaxation process of the alloys is associated with the formation of energetically stable icosahedra and icosahedron-like structures. Our study highlights the effects of sub-T_gannealing on the improvement in the corrosion resistance of the amorphous alloys from the viewpoint the relaxation process of the short-range orders.     

汽车发动机用镁合金的耐腐蚀性研究

采用失重法、腐蚀形貌观察、XRD标定和腐蚀极化曲线等方法,研究了汽车发动机用Mg-11Li-3Al-1Ca和Mg-11Li-3Al-1Ca-1Ce合金在Na Cl溶液中的腐蚀行为及其作用机理。结果表明,Mg-Li-Al-Ca合金表面附着的腐蚀产物以Mg(OH)2为主,腐蚀产物较少、较薄,分布不连续、不均匀,不能有效抑制腐蚀的发生。Mg-11Li-3Al-1Ca-1Ce合金的腐蚀产物中含有Al(OH)3和Ca(OH)2,腐蚀产物更加致密、连续,可以对合金基体起到有效地保护。     

化学镀Ni—W—P合金镀层耐磨耐蚀性研究

通过对化学镀Ｎｉ—Ｐ层进行合金化，获得了一种含Ｗ９．７％．Ｐ５．９％的Ｎｉ—Ｗ—Ｐ三元合金镀层。研究表明该镀层具有良好的热稳定性，在６００℃×１ｈ热处理后，其硬度值达到峰值（约为ＨＶ（１００）１０６０）；其耐磨性优于Ｎｉ—Ｐ镀层；在１Ｎ的ＨＣｌ溶液中，和Ｎｉ—Ｐ层比较，其耐蚀性稍差。     

Surface Treatments for Enhanced Wear Resistance of Aluminium

This report presents a survey of various surface treatments to improve the wear resistance of aluminium. Over 25 different treatments have been produced and evaluated in laboratory and in application tests. Three plastically formable alloys and one pressure die casting alloy were included.

The different coating systems have been characterised with respect to structure and morphology by scanning and transmission electron microscopy. The laboratory wear tests were performed by using Taber abraser and pin on disc as standard methods. As a comparison, a non-standard reciprocating adhesive wear test set-up was used. In addition, a corrosion test by accelerated outdoor exposure (SCAB) was performed. The application tests were a rotating PTFE sealed sleeve, a station chain in a food packing machine and a yarn feeder.

The results from the abrasive and adhesive laboratory wear tests have been correlated to the results in the application tests. For some of the evaluated coating systems the correlation between the laboratory and the application tests is reasonably good. However, substantial difference in performance was found for other systems.     

医用CoCrMoC合金的组织结构及耐磨损性能

以铸造CoCrMoC合金（ASTMF 75-82）为研究对象，通过金相观察，XRD，SEM和EDX分析以及磨损试验，研究了该合金在不同热处理条件下的显微结构与耐磨损性能。结果表明：不含C的CoCrMo合金的耐磨损性能几乎不受热处理制度的影响：含C的CoCrMoC合金在1100℃以上温度固溶处理耐磨损性能明显提高，其中1200℃是最佳温度，固溶后时效处理降低合金的耐磨损性能。分析认为，固溶引起的fcc钴基体固溶强化和适当的碳化物分布是提高耐磨损性能的主要原因，而时效引起的基体fcc相→hcp相的等温马氏体相变对耐磨损性能影响不大。     

Nd对Zr基非晶合金形成能力、热稳定性及耐腐蚀性的影响

利用铜模吸铸法在水冷坩埚中制备了4种(Zr0.55Al0.1Ni0.05Cu0.3)100-xNdx(x=0,1,2,3)块体非晶合金。采用XRD和DSC检测了所获合金相组成、非晶形成能力及热稳定性,并采用盐酸溶液浸泡腐蚀试验评价了不同合金的腐蚀速率。结果表明,适量添加Nd可提高Zr0.55Al0.1Ni0.05Cu0.3非晶合金的形成能力和热稳定性,但非晶合金在2mol/L HCl溶液中的耐蚀性随Nd含量的增加而降低。该结果对进一步改善和提高非晶合金的性能具有重要的参考价值。     

Ni-Ta-Sn非晶合金的耐腐蚀性能

用单辊甩带方法制备了Ni-Ta-Sn非晶合金薄带,用失重法和室温动电位极化法研究了该薄带在酸、碱、盐等腐蚀介质中的腐蚀行为,并与典型Zr-Ti-Cu-Ni-Be非晶合金以及1Cr18Ni9Ti不锈钢进行了对比.结果表明,Ni-Ta-Sn非晶合金比Zr-Ti-Cu-Ni-Be具有更低的腐蚀速率,且抗腐蚀性能远远优于1Cr18Ni9Ti不锈钢.     

Ti基大块非晶的耐磨性研究

采用销-盘法研究了Ti11.5Zr2.5Hf5Cu42.5Ni7.5Si1大块非晶及其经432℃退火和477℃退火后的耐磨性,并用AFM研究了磨损面的形貌.随着退火温度的升高,耐磨性和显微硬度都有所提高.经磨损实验后,试样的磨损面显微硬度提高,有加工硬化现象出现.非晶态试样的磨损以局部剪接的塑性流变为主,经退火试样还存在脆性断裂.     

Fe－B－C合金冲击磨料磨损性能及磨损机制的研究

以高铬铸铁为对比材料,采用MLD-10型冲击磨料磨损试验机,研究了Fe—B—C合金冲击磨料磨损性能：借助子扫描电镜,探讨了Fe—B—C合金的磨损机制。结果表明：Fe—B—C合金的硬度和冲击韧度与高铬铸铁相当,耐磨性能达到高铬铸铁水平,具有良好的性价比;Fe—B—C合金的磨损机制是以微观切削为主,同时存在微观断裂和微观犁沟的混合磨损。     

Fe基非晶及纳米晶合金的制备和电化学腐蚀行为

分别采用单辊甩带法和非晶晶化退火法制备出非晶及纳米晶合金Fe73.5Si13.5B9Nb3Cu1;利用DSC、XRD和TEM对该非晶合金的晶化行为进行了分析;并用电化学极化曲线的方法和电化学阻抗技术研究了该非晶合金经不同温度退火后在1mol/LHCl溶液里的电化学腐蚀行为。结果表明,该非晶合金的晶化过程出现2个阶段。当退火温度为500℃时,合金尚未晶化,仍保持非晶态;当温度达到550℃时,出现了晶化衍射峰,晶粒平均直径约13nm;当温度达到600℃时,晶粒平均直径约为15nm。经过退火得到的纳米晶合金的腐蚀电位大于未退火的非晶,且阳极电流密度变得更低,表明纳米晶状态时的耐腐蚀性能比非晶状态的更好。该非晶合金未退火、550℃退火和600℃退火时的EIS均由单一容抗弧构成,具有一时间常数;且随着退火温度升高,电化学反应电荷转移电阻在增大。