KI体系下制备纯银镀层和纯银/银石墨复合镀层的性能

在KI体系下使用电沉积方法在铜基体表面分别制备了纯银镀层和纯银/银石墨复合镀层,研究了两种镀层的结合力、耐磨性、耐蚀性、热导率和电阻率。结果表明:在KI体系下制备的纯银镀层和纯银/银石墨复合镀层与铜基体的结合力都达到GB/T 5270-2005标准要求;纯银/银石墨复合镀层的平均摩擦因数和磨损率分别为0.178和2.457×10-11 mm3·N-1·m-1,远远小于纯银镀层的0.515和6.501×10-11 mm3·N-1·m-1,其耐磨性优于纯银镀层的,但其耐蚀性比纯银镀层的差;纯银/银石墨复合镀层的热导率明显优于纯银镀层的,电阻率高于纯银镀层的。     

熔炼方法对银熔体材料纯度、组织和电性能的影响

分析了熔炼方法对银熔体材料纯度、微观组织和电阻率的影响。对比普通熔炼方法,二次熔炼方法得到的银材料由II号银(99.95%)变成I号银(99.99%);氧含量降低至少85%以上,纯银熔体材料电阻率降低约1.54%。杂质元素主要集中在晶界处,纯银熔体材料电阻率随杂质含量的减少而减小,二次熔炼方法可有效提高纯银熔体材料质量、稳定其电学性能。     

退火热处理对氧化铝表面铜膜微观形貌和性能的影响

以氧化铝为基底,利用磁控溅射镀膜设备在其表面制备铜膜,研究退火热处理工艺对铜膜微观形貌和性能的影响。结果表明,退火热处理对氧化铝铜膜的表面粗糙度、电阻率和膜基结合力均有明显影响。退火热处理后,氧化铝铜膜的表面粗糙度明显增加。     

脉冲偏压对贫铀表面磁控溅射CrN_x薄膜结构与性能的影响

为改善金属铀基体的抗腐蚀性能,采用非平衡磁控溅射离子镀技术在不同偏压下于金属铀表面制备CrNx薄膜。采用SEM和AFM研究了薄膜形貌和表面粗糙度,采用X射线光电子能谱研究了薄膜表面的元素分布及化学价态。试验结果表明,采用磁控溅射在较低脉冲偏压下沉积的CrNx薄膜晶粒较细小,偏压越高,表面粗糙度越大。生成的薄膜为Cr+CrN+Cr2N混合结构,并含有少量的Cr2O3,随着偏压的升高,金属态Cr的含量减少,而铬的氮化物的含量增加,所制备薄膜的自然腐蚀电位升高,腐蚀电流密度减小。偏压为-800 V时,所制备的薄膜具有较好的抗腐蚀性能。     

热处理对氧化铝陶瓷表面铜膜性能的影响

采用射频磁控溅射方法在Al2O3陶瓷基底上淀积厚度为500 nm的Cu膜,并将其于真空热处理炉中采用30℃/min和5℃/min两个升温速率升温至400℃退火处理2h,研究了退火升温速度对铜膜表面形貌、电阻率及附着力的影响.结果表明:退火热处理使Cu薄膜表面粗糙度增加,铜膜电阻率降低,膜-基结合力增强.且30℃/min快速升温较5℃/min缓慢升温退火热处理,Cu薄膜表面粗糙度低,Cu薄膜表面电阻率低,膜-基结合力差.利用自由电子气理论和扩散理论对退火热处理过程引起的性能变化进行了分析解释.     

钛双极板表面原位生成TiN涂层的性能研究

目的降低钛合金表面的接触电阻,提高其抗腐蚀性能。方法 TA2纯钛表面进行活化后,原位反应生成TiN涂层。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和能谱仪(EDS)分析表面形貌和成分,使用直流表面电阻和界面接触电阻(ICR)来评价涂层的导电性,在模拟质子交换膜燃料电池(PEMFC)环境中测试其抗腐蚀性能。结果经过TiN处理后的TA2纯钛双极板表面致密,其生长方式为沿(111)晶面择优生长。在750℃反应2 h获得的试样的直流表面电阻和ICR电阻最低,抗腐蚀性能最佳。压力为120N/cm^2时,电阻率稳定在6.7 m?/cm^2。在模拟PEMFC环境中的表面腐蚀电流为0.816μA/cm^2,经过恒电位扫描后的SEM显示,其表面完整,H2气氛中涂层界面完整,空气气氛中出现较多点蚀。结论在TA2纯钛表面原位反应生成TiN涂层有助于提高基体表面的抗腐蚀性和导电性。     

发动机曲轴专用抛丸强化清理机的研发与应用

发动机曲轴专用抛丸强化清理机是专门用于对汽车曲轴表面进行清理强化的一种清理设备。它通过抛丸器抛出高速弹丸,打击在曲轴的表面,除去表面氧化皮及其它附着物,并对表面进行强化处理。曲轴经过抛丸清理后,表面获得均匀的粗糙度,同时消除了应力集中,提高了曲轴的抗疲劳、抗腐蚀性能,延长了曲轴的使用寿命。该设备特别研发了分体式抛丸器,转速高、噪音小;研发了抛打和上卸料两个工位的转台,可实现一个工位进行工作,另一个工位进行上卸料,效率提高一倍。     

盐雾环境下5A06铝合金的腐蚀行为

本文以5A06铝合金为研究对象，精加工零件表面，采用本色导电氧化制备氧化膜，并通过盐雾试验研究铝合金在盐雾腐蚀条件下的抗腐蚀性能。结果表明：在盐雾条件下，铝合金表面腐蚀为点蚀，本色导电氧化后铝合金的耐腐蚀能力增强，表面粗糙度越高，越易发生腐蚀凹坑，且腐蚀凹坑多沿加工痕迹分布。     

表面金属陶瓷化进展

表面金属陶瓷化处理是提高材料抗腐蚀性能、强化材料的表面质量及修复各种仪器零配件、机械零配件公差的一项新兴的表面处理技术和工艺。目前,特别是含铬的表面金属陶瓷化处理,其抗腐蚀性能远远超过了不含铬的金属玻璃化表面处理,达到金属钛的抗腐蚀水平。并且,在机械强度、硬度性能方面不与抗蚀性能相矛盾。这点比不含铬的金属陶瓷化处理进了一大步。众所周知,不含铬的金     

离散铬纳米核对超薄铜箔剥离性能和电阻率的影响（英文）

提出一种利用电化学沉积法制备Cr纳米离散晶核实现超薄铜箔剥离的策略。结果表明,该方法可以制备厚度约为1.34μm的铜箔。Cr纳米离散晶核密度直接影响铜箔的剥脱性能、表面粗糙度和电阻率。当Cr纳米离散晶核密度为15.7×10⁹ cm^-2时,铜箔的剥离性能最好,电阻率为4.95×10^-7Ω·m,比常规厚度为0.67μm Cr涂层的电阻率低9.2%,比重铬酸钾涂层的电阻率低15.8%,抗拉强度超过248.80 MPa。     

Susceptibility of chloride ion concentration,temperature, and surface roughness on pitting corrosion of CoCrFeNi medium-entropy alloy

The influence and susceptibility of chloride ion concentration, temperature, and surface roughness on corrosion behavior of single-phase CoCrFeNi medium-entropy alloy (MEA) was examined in NaCl solution. Potentiodynamic polarization results revealed that the corrosion performance of the sample deteriorated with an increase of the chloride ion concentration, temperature, and surface roughness. The pitting potential decreased drastically for samples with higher surface roughness. According to electrochemical impedance spectroscopy, the charge transfer resistance decreased when chloride ion concentration, temperature, and surface roughness increased. Scanning electron micrographs also indicated an increased extent of corrosion damage, especially for the sample with higher surface roughness. It is found that the corrosion resistance is closely related to the wettability of samples, and the surface with the highest roughness shows higher hydrophilicity. The combined results suggested that the pitting damage is more sensitive to surface roughness. Our findings provide a further understanding of the corrosion mechanism of MEAs and guide their applications as structural materials.     

Influence of Ultrasonic Rolling on Corrosion Resistance of 7075 Aluminum AlloyEI北大核心CSCD

表面纳米化处理是一种有效改善耐腐蚀性能的手段,但受表面粗糙度和残余应力等因素的影响,其相关机制并不清晰。 运用透射电镜(TEM)和扫描电镜(SEM)研究经超声表面滚压工艺(USRP)处理后 7075 铝合金的组织和性能。结果表明： 经 1 道次和 15 道次 USRP 处理后,7075 铝合金表面粗糙度减小并且引入了残余压应力。滚压 15 个道次的试样表面能获得平均晶粒尺寸为 52 nm 的纳米晶。相较于未处理试样,经 1 道次和 15 道次 USRP 处理后试样的耐腐蚀性能均显著提高。其中, 滚压 15 个道次试样的耐腐蚀性能提升更为显著。这主要是因为纳米晶可以使材料表面形成更加致密的钝化膜,导致其耐腐蚀性能显著提高,而表面粗糙度降低和引入残余压应力是提升耐腐蚀性能的次要因素。对比分析残余应力、表面粗糙度和表面纳米晶对 7075 铝合金耐腐蚀性能的影响,揭示了 7075 铝合金经表面纳米化处理后耐腐蚀性能提升的机制。     

表面粗糙度对锌涂层防腐性能的影响

通过极化电阻及腐蚀电位长时间的测试,研究了电弧喷涂锌涂层在3．5％NaCl溶液中电化学行为。实验结果表明：锌涂层表面粗糙度在浸泡初期与腐蚀产物联合控制着腐蚀的过程,但以表面粗糙度的控制为主。浸泡后期主要表现为腐蚀产物的控制。     

Stress corrosion cracking of gas pipelines - Effect of surface roughness, orientations and flattening

The primary corrosion mitigation of the external surface of high pressure steel gas pipelines is protective coatings with secondary protection usually by cathodic protection. Adhesion and resistance to cathodic disbondment of the coating is critical for its integrity and grit blasting is an important process in achieving this adhesion. The effect of surface roughness, from grit blasting, on the intergranular stress corrosion cracking resistance of X70 gas pipelines was investigated using slow strain rate testing in carbonate/bicarbonate solution at 75 °C. The effect of orientation of test pieces with respect to the axial direction of pipes was also investigated.Time to failure ratios decreased with increasing surface roughness indicating reduced stress corrosion cracking resistance. The reduced resistance to cracking with increasing roughness would be predominantly associated with stress concentration effects related to the surface roughness resulting from the grit blasting. Crack concentration decreased with increasing roughness, which is likely to be associated with the concentration of surface damage from the grit blasting using varying sized grit. As formed pipe surfaces, with no grit blasting, resulted in some of the lowest time to failure ratios and hence some of the lowest resistances to stress corrosion cracking. These also showed some of the deepest cracks. The influence of roughness and residual stresses on threshold stress is currently being investigated.Time to failure ratios indicated a greater resistance to stress corrosion cracks for circumferentially orientated test pieces compared to those longitudinally orientated. Whilst further testing would be required for confirmation, the current results suggest that flattening the test pieces had only a minor, if any, effect on stress corrosion cracking susceptibility as measured by slow strain rate testing to fracture.     

0Cr18Ni9不锈热轧带钢表面锈蚀原因分析

太原钢铁（集团）有限公司生产的0Cr18Ni9不锈热轧带钢退火酸洗后钢卷表面局部发生锈蚀,严重影响产品的加工使用。通过盐雾腐蚀试验,研究了化学成分、夹杂物级别以及表面粗糙度等对0Cr18Ni9热轧板表面耐蚀性的影响。研究表明,钢中ω（Cr）≥17.5%、ω（S）≤0.005%、无表面夹杂物、以及具有低的表面粗糙度,可有效提高热轧不锈带钢的耐蚀性。     

Microstructural and corrosion resistance characterisation of NiTi shape memory alloy modified at low-temperature plasma with carbon coatings produced via RFCVD and IBAD methods

ABSTRACT

NiTi shape memory alloy, both before and after low-temperature oxynitriding under glow discharge conditions combined with the production of a nano-sized outer carbon coating, was investigated. The study compares two types of carbon coatings: produced via the RFCVD (radio frequency chemical vapour deposition) and IBAD (ion beam-assisted deposition) methods. The latter was also enriched by randomly distributed silver nanoparticles. The study showed slight changes in roughness parameters and increased corrosion resistance after surface treatment processes. The largest impedance module and corrosion potential and the smallest density of corrosion current were achieved for samples with a carbon coating produced via the RFCVD process. The presented surface modifications using hybrid processes can extend the use of NiTi alloy in medicine due to the increased biocompatibility.     

超疏水Ni-P-Al2O3纳米复合镀层的制备及耐腐蚀性能研究

为提高45钢基体材料的耐腐蚀性能,采用电化学法与氟硅烷修饰相结合的方式在45钢基体表面制备超疏水Ni-P-Al2O3纳米复合镀层,并对镀层的表面形貌、晶相结构、表面粗糙度、润湿性及耐蚀性能进行了研究。结果表明:采用电沉积法制备的Ni-P-Al2O3镀层表面均匀、致密,且无明显气孔缺陷,接触角测试表明其表面达到了超疏水状态,而经电化学加工后,镀层表面形成不规则的微凹坑结构,表面粗糙度值明显增大。经电化学测试,与普通Ni-P-Al2O3镀层相比,超疏水Ni-P-Al2O3镀层的腐蚀电流密度、腐蚀速率均更小,表现出优异的耐腐蚀性能。     

表面强化处理对工业纯钛焊接接头电化学腐蚀性能的影响

为了改善焊接接头的性能,延长其使用寿命,实验采用喷丸强度为0.15A的超声喷丸处理(USSP)方式对工业纯钛TA2焊接接头进行强化。通过OM、SEM、TEM分别对TA2焊接接头各区域组织及腐蚀形貌进行观测,对不同工艺处理试样的残余应力值、表面粗糙度进行了测定,并对超声喷丸后试样表面进行热处理和表面打磨,研究了不同表面残余应力及表面粗糙度对焊接接头焊缝区域在80℃ 的10% HCl溶液中的电化学腐蚀性能。结果表明,USSP强化处理纯钛焊接接头耐腐蚀性能有所提升。经退火处理后,随着退火时间的增加,耐腐蚀性能先增加后降低,退火0.5h时,自然腐蚀电位最高,电流密度最低,耐腐蚀性能最优。经表面打磨处理,腐蚀速率主要由扩散步骤控制,产生浓差极化,随着打磨强化层的增加,扩散速率加快,耐腐蚀性能有提高。打磨至强化层2/5处时,耐腐蚀性能提升明显。     

Galvanic corrosion behavior of Ni?C filled conductive silicone rubber coupled to AZ31 magnesium alloys

The galvanic corrosion behaviors of Ni? C filled conductive silicon rubber (CSR) with different resistivity coupled to magnesium alloys were investigated in 3.5% sodium chloride solution at different temperatures. Such investigations were carried out by means of electrochemical measurement, weight‐loss determination, and surface characterization. The results indicated that the changes of CSRs' resistivity and the temperature of the electrolyte would affect the Tafel slope, cathodic corrosion current, and linear polarization resistance of the cathodic branch of the polarization curve. The lower the resistivity, the larger the average galvanic corrosion current density and the average galvanic corrosion rate of Mg alloys at the same temperature. The corrosion morphology revealed that the greater the corrosion current density, the more serious the corrosion on the surface of Mg alloys.     

The effect of mechanical polishing and finishing on the corrosion resistance of AISI 304 stainless steel

The aim of the present work was to study the influence of surface finishing on the corrosion resistance of AISI 304 stainless steel samples. Samples were submitted to lathe-turning, milling, lapping and grinding. Roughness parameters were determined by confocal laser scanning microscopy (CLSM). The corrosion resistance was evaluated using potentiodynamic polarisation curves and the corrosion morphology was assessed using CLSM and scanning electron microscopy. The results showed that the surface state had a remarkable influence on the corrosion behaviour of the samples, especially surface imperfections, whereas the roughness parameters did not directly correlate with the corrosion resistance.