电化学阻抗谱研究Zn对用于阴极保护的Al-Zn合金在3%NaCl溶液中溶解行为的影响（英文）

采用电化学阻抗谱(EIS)研究了Al-Zn合金在不同极化电位下,3%NaCl溶液中的溶解行为,提出了Al-Zn合金在该条件下的活化反应模型及机理。该活化反应中产生3个中间产物:Zn_(ad)~+、Zn_(ad)~(2+)和Al_(ad)~+,其中只有Zn_(ad)~+可以活化Al-Zn合金。大部分Zn_(ad)~+由β相反应产生,Zn含量2.3%-3.8%wt的Al-Zn合金可以快速溶解。具有心形EIS的Al-Zn合金在该溶液中处于活化状态,因此采用EIS可以区分Al-Zn合金的活化状态。     

微量银对Sn-9Zn合金电化学腐蚀行为的影响

采用电化学测试、扫描电镜观察、能谱分析等方法,研究了添加质量分数为0.5%的银元素对Sn-9Zn合金在3.5%NaCl溶液中电化学腐蚀行为的影响。结果表明:Sn-9Zn合金中均匀的显微组织使腐蚀原电池反应较为均匀,表面锌相作为腐蚀原电池的阳极几乎完全发生了腐蚀溶解;在添加0.5%银的Sn-9Zn合金中,局部形成银锌金属间化合物(IMC),合金成分与组织的不均匀导致腐蚀原电池反应不均衡,合金的自腐蚀电位略有提高,且会发生以锡相为阳极、富银相为阴极的腐蚀原电池反应。     

滑动轴承合金耐磨性能规律的探讨

采用MPX-2000型销-盘式摩擦磨损试验机对ZA30、ZCuSn6Zn6Pb3、ZCuAl10Fe3、ZCuSn10P1这4种滑动轴承合金在不同载荷、不同润滑条件下的耐磨性能进行了对比试验,并在扫描电子显微镜上观察了磨损表面形貌,探讨了磨损机理。结果表明：当4种合金都处于低位磨损状态时,其耐磨性的次序为：ZA30〉ZCuSn10P1〉ZCuSn6Zn6Pb3〉ZCuAl10Fe3;随着载荷、润滑等工况条件的变化,合金会由低位磨损状态（磨粒磨损）向剧烈磨损状态（粘着磨损）转化,其转化次序为ZCuSn6Zn6Pb3〉ZCuSn10P1〉ZA30〉ZCuAl10Fe3,4种合金的耐磨性次序相应改变。     

高耐蚀低脆性锌──钛合金电镀层工艺研究

Zn－Ti合金工艺成功地解决了钛盐易水解的问题，溶液稳定，达到29安培小时／升。合金镀层中钛含量可以稳定地控制在0．3～0．5％，保证合金镀层耐蚀性比普通锌高两倍以上，并具有优良的抗有机酸腐蚀的性能。Zn－Ti合金工艺可以从锌酸盐和低氰镀锌溶液进行直接转换，不需要更换设备，是提高镀锌层质量较经济的工艺。Zn－Ti合金除氢性能好，镀层结合强度高，适合干高强钢防氢脆应用，并可用作代钢镀层。该成果，经武汉汽车标准件厂用于桑塔纳汽车车轮紧固螺栓电镀、710厂用于电子设备零部件上电镀，其耐蚀性能优于原锌镀层。天津发电设备总…     

快速凝固Mg-Zn-Y合金薄带组织和性能研究

在成功制备不同成分Mg—Zn—Y合金急冷快速凝固薄带基础上，利用XRF和XRD分析其成分和组织特点及其组织变化规律，采用腐蚀失重法、盐雾实验法、显微硬度测量等方法，系统研究了不同成分Mg—Zn—Y合金急冷快速凝固薄带的耐蚀性能和硬度变化规律。结果表明，随冷却速度的增大，Mg—Zn—Y合金凝固组织具有非晶化的趋势；MgZnY母合金块及其薄带在1％HCl、10％NaOH和5％NaCl溶液中腐蚀性能表现出相似的规律；在成分和冷却速率相同的条件下，Mg—Zn—Y合金的耐蚀性在10％NaOH溶液中最好，5％NaCl溶液中次之，而在1％HCl溶液中最差；在成分相同的条件下，随着冷却速度的增大，Mg—Zn—Y合金的显微硬度增大，而且薄带的显微硬度比同成分母合金块的高50％以上。最后，本文还对上述研究结果进行了初步分析。     

GH4169合金细晶成形工艺与机理及其性能研究

用热机械加工和光学与扫描电镜观察的方法 ,对GH4 16 9合金板材的δ相析出规律及其超细化工艺进行了研究。结果表明 :对GH4 16 9合金板材进行 890℃× 10h处理 ,可以析出足够数量的针状δ相 ,该相具有良好的热稳定性 ;对该板材采用 10 5 0℃× 0 .5h + 5 0 %冷轧变形 + 890℃× 10h + 2 0 %～ 30 %冷轧变形 + 95 0℃× 3h的工艺后 ,可以得到ASTM 12～ 14级的超细晶粒组织 ;所获得的超细晶合金与普通合金相比 ,其 6 5 0℃高温抗拉强度及伸长率均有所提高     

热处理工艺对CuAl2初熔与溶解行为的影响*

研究了热处理工艺对Sr变质Al-10％Si-3％Cu-0.3％Mg合金组织中CuAl2初溶与溶解行为的影响.通过显微组织观察,对Sr变质Al-10％Si-3％Cu-0.3％Mg在不同固溶处理温度下的合金组织进行了研究.结果表明,在500℃×4h(或500℃×4 h+515℃×4 h)下固溶处理,随着时间的延长,富铜相的溶解量增多,同时在535℃下出现了富铜相的熔化.研究还发现,与1步固溶工艺相比,2步固溶处理工艺下富铜相更能充分溶解.     

Ti-44Al-5Nb-0.85W-0.85B高温蠕变性能的初步研究

采用不同热等静压工艺,对一种含铌-钨的钛合金Ti-44AI-5Nib-0.85W-0.85B(at%)进行处理后.得到含有B2+ω相和不含B2+ω相的全片层组织;研究了该合金的这两种全片层组织在700℃,15～300 MPa大气气氛条件下的蠕变性能;结果显示,含铌-钨TiAI合金拥有良好的抗蠕变性能;在晶界偏聚少量B2+ω有序相并不降低该含铌-钨TiAI合金的高温抗蠕变的性能.     

多元陶瓷相在激光熔覆层中的溶解机制研究

激光熔覆层材料以铁基粉末为基础,添加有TiC、WC和SiC多元陶瓷增强相。依据自由能变理论,对激光熔覆过程中的涂层化学反应方向与反应程度进行了热力学分析,研究了所添加陶瓷增强相的溶解机制,结果表明：在设定的工艺参数和激光作用下,涂层表面可产生2 000~3 000 K的高温,通过显微组织分析可以发现,在上述温度范围内陶瓷物质发生了部分甚至完全溶解,且熔池中熔化游离的Fe、Cr、Ni等离子或颗粒先后与陶瓷物质中分解出的Ti、W、Si与C元素发生再反应与互溶,形成了具有一定金属性以及陶瓷相强度和硬度的物质,如FeNi2Ti、Fe-Cr-Ni-Si等新合金相或固溶体,并达到了强化涂层性能的效果。研究结果与理论模型分析结果规律相同。     

喷砂钝化对硬质合金数控刀片腐蚀行为的影响研究

针对硬质合金数控刀片刃口制备工艺,采用喷砂钝化取代传统的毛刷钝化后,表面微观组织发生显著变化,可能会导致合金生产制备过程中腐蚀行为的变化。系统研究了在自来水、NaHCO₃溶液和酒石酸溶液中喷砂钝化对合金腐蚀行为的影响,研究结果显示：喷砂钝化显著提高了合金在自来水、NaHCO₃溶液和酒石酸溶液中的抗腐蚀能力,WC和Co相在不同的腐蚀介质中显示出不同的腐蚀行为,在中性和碱性溶液中以Co的氧化为主(碱性溶液中伴随着W的溶解),在酸性溶液中以Co的溶解为主。合金腐蚀性能的提高主要是由于喷砂钝化过程中基体表面WC颗粒破碎,较小WC颗粒填充在大WC颗粒之间,并被Co相包裹,有效降低了发生缝隙腐蚀的概率。此外,喷砂钝化过程中表面极易形成致密的CoO钝化膜,有效避免了Co相与WC颗粒进一步被腐蚀。     

稀土对AZ91镁合金耐腐蚀性能的影响

利用静态失重、极化曲线和交流阻抗测试等方法研究了AZ91合金和AZ91 RE合金在NaCl溶液中的腐蚀规律；利用金相显微镜及电子探针分析了腐蚀试样的表面和截面形貌；对腐蚀脱落产物进行了XRD鉴别。结果表明，稀土元素显著提高了AZ91合金在NaCl溶液中的耐腐蚀性能。其作用机理主要在于稀土元素的以下三个作用：改变了合金腐蚀层结构；强化了阴极相控制；影响合金腐蚀的电化学过程。三方面的综合作用，使AZ91合金在NaCl溶液中的耐蚀性有了较大的改善。     

Effects of cobalt on high rate dissolution behaviour of nickel-base superalloys in NaNO3 and NaCl solutions

The dissolution behaviour of Ni-12% Cr-Co and Ni-20% Cr-Co alloys containing from 0% to 40% cobalt has been studied in 3 mol dm⁻³ NaNO₃ and 2 mol dm⁻³ NaCl solutions at 30° C. The anodic polarization curves and the dissolution current efficiency were measured in a flow cell. The results show that cobalt facilitates the dissolution of the alloys, dissolving as divalent Co²⁺ ions under electro-chemical machining conditions. For the Ni-12%Cr-Co alloys which exhibited secondary passivation and oxygen evolution in NaNO₃, increasing the cobalt content to 20% or more resulted in secondary transpassive dissolution. A decrease in the degree of the secondary passivity was observed for those alloys which had a high cobalt content, comparable with their nickel content. However, the Ni-20% Cr-Co alloys in NaNO₃ and all the alloys studied in NaCl dissolved with 100% current efficiency due to the marked effects of chromium; the effects of cobalt had only secondary significance. X-ray photoelectron spectroscopic study indicates that in the surface layers formed in the transpassive and secondary passive states cobalt exists in the +2 oxidation state, such as CoO and/or Co(OH)₂.     

Microscopic evaluation of the dentinal walls of extracted human teeth following electrochemical dissolution of fragmented nickel–titanium instruments

Electrochemical dissolution is a method in which fluoridated solution in direct contact with the fractured instrument receives an electrical current that speeds up fragment dissolution. The aim of this study was to assess the integrity of dentinal walls during the electrochemical dissolution of fractured rotary endodontic instruments in extracted human teeth. Forty‐five human mandibular incisors subjected to the electrochemical dissolution process using fluoride solution with low NaCl concentration (LC group: NaF 12 g/L + NaCl 1 g/L, pH = 5.0), fluoride solution with saturating NaCl concentration (SC group: NaF 12 g/L + NaCl 180 g/L, pH = 5.0) and distilled water (control group) were evaluated. For each group, 15 incisors were submitted for the scanning electron microscopy (SEM) evaluation. The roots were sectioned longitudinally; each hemisection was analyzed (n = 30), and energy‐dispersive spectroscopy (EDS) was performed. The amount of dentinal tubule openings was analyzed by SEM. Statistical analyses were performed. The test solutions did not alter the amount of dentinal tubule openings when compared with the control group. No Ni or Ti was impregnated into the dentinal tubules after electrochemical techniques. The dentinal structure remained unchanged following the electrochemical dissolution method.     

周浸加速循环腐蚀试验中耐候钢锈层的电化学特征

通过周浸加速腐蚀试验研究了耐候钢和碳钢在3．5％NaCl溶液中的腐蚀情况。试验结果表明：腐蚀200h的耐候钢表面生成的致密锈层主要由α-CrxFe1-xOOH组成。通过人工合成相应组分的腐蚀产物，并测试其离子选择性，发现该锈层有阳离子选择特性，能阻挡氯离子进入，降低钢的大气腐蚀速率；电化学交流阻抗（EIS）分析表明耐候钢的腐蚀过程主要由扩散控制。     

Triboelectrochemical behaviour of a Si3N4–TiN ceramic composite and a titanium alloy commonly used in biomedical applications

In this paper the corrosion and tribocorrosion behaviour of a traditional metallic biomaterial (Ti6Al4V) and a Si₃N₄/TiN (SN/TiN) ceramic composite are studied and compared during exposures to 1% NaCl and 1% NaCl + 1% lactic acid solutions.Electrochemical impedance spectroscopy (EIS) data collected on Ti6Al4V in both neutral and acidic solution have been interpreted on the basis of a double layer surface oxide film, which is completely removed from the wear track during the sliding tests. Under these conditions, the impedance of the depassivated region dominates the overall electrode impedance.Previous EIS tests performed on SN/TiN evidence that even this material exposed to neutral solution is covered by a double layer film, while a porous monolayer film forms in acid solution. Under pure corrosion conditions, SN/TiN exhibits corrosion rates which are quite comparable to those measured on Ti6Al4V. During tribocorrosion tests the EIS response of the ceramic material does not change much. Its corrosion rates are two orders of magnitude lower than those measured on Ti6Al4V.Profilometer analysis shows that on both materials most of overall tribocorrosion damage is due to mechanical wear.The tests suggest that SN/TiN is a promising biomaterials for applications where sliding conditions occur.     

Observations of lattice defects using the weak-beam technique

The advantages of the weak-beam technique of electron microscopy for the study of small defects and dislocations are illustrated by micrographs taken of small loops in aluminium and Al–Ag alloys, GP zones and θ″ precipitates in Al + 4% Cu, and dislocation networks in Cu + 20% Zn. An estimate of 19·5 mJ m^?2 (erg cm^～2) is made for the stacking-fault energy of Cu–20% Zn from the size of extended nodes and the width of the dissociated dislocations imaged under weak-beam conditions.     

石油管线钢在H2S/CO2环境中腐蚀行为的电化学研究

采用极化曲线法和交流阻抗法研究了15#钢在H2S/CO2环境下的电化学行为.试验结果表明,H2S和CO2的存在加速了15#钢在NaCl溶液中的腐蚀速率,管线钢在NaCl溶液、NaCl-CO2溶液、NaCl-CO2-H2S溶液以及NaCl-H2S溶液中电化学反应过程所受的阻力愈来愈小,腐蚀电流密度越来越大,腐蚀速率越来越...     

CuAlSn合金表面腐蚀层的XPS研究

文章运用XPS对CuAISn合金在3.5%NaCl水溶液中腐蚀层的化学成分、元素状态及相分布进行了分析.结果表明,腐蚀层存在有一价态铜、三价态铝和二价态锡,形成了Cu2O相和Al2O3相,也有可能形成SnO相,它们的分布深度存在差异.     

不同腐蚀环境下高强铝合金腐蚀行为

针对航空铝合金材料在服役过程中因恶劣环境而导致材料腐蚀的问题,通过分析腐蚀形貌、腐蚀坑开口面积、腐蚀深度、点腐蚀坑数量、pH值、腐蚀产物等变化,研究2xxx航空铝合金在不同腐蚀环境(3.5%NaCl水溶液、模拟油箱积水溶液和潮湿空气)中的腐蚀行为和机理。结果表明,在3.5%NaCl水溶液中,铝合金试样表面腐蚀坑的产生主要发生在前24h内,其最大腐蚀坑深约为45μm,而在72~120h, 随预腐蚀时间的延长,腐蚀坑深度、个数的增加并不明显;铝合金试样在模拟油箱积水环境中的腐蚀规律与在3.5%NaCl水溶液中的相似,但腐蚀坑最大开口面积和腐蚀坑的个数明显减少;与前两种环境相比,试样在潮湿空气环境中的腐蚀程度明显减小,腐蚀坑总体个数最少,最大腐蚀坑深约在20μm以内,最大开口面积约在5000μm²左右,且随着腐蚀时间的增长,腐蚀坑之间的深度差距越来越小。     

Corrosion measurement of Sn–Zn lead-free solders in 6 M KOH solution

The corrosion measurements of Sn–Zn alloys with varying Zn contents from 0 wt.% to 12 wt.% were investigated in a 6 M KOH solution. The corrosion parameters of this series of materials, which include open circuit potential, galvanic corrosion current, corrosion potential, and corrosion current, were studied. The Sn–Zn alloys initially revealed an activity similar with that of pure Zn in this 6 M KOH solution. The alloy activity became more inert when the corrosion analysis was prolonged. In addition, phase and morphological analyses results confirmed the formation of mixed corrosion products on the surface after polarisation.