Entwicklung,Eigenschaften, Verarbeitung und Einsatz des hochsiliciumhaltigen austenitischen Stahls X2 CrNiSi 18 15

Development, Properties, Processing and Applications of High-Silicon Steel Grade X2 CrNiSi 18 15 Production, storage and transportation of highly concentrated nitric acid (approximately 98%) frequently occur in containers and vessels made of pure aluminium. In many cases, however, their service life is restricted by the insufficient corrosion resistance of the welds. Though tantalum exhibits a superior resistance to corrosion, it is only used in very specific occasions for cost considerations. Commercial grade austenitic chromium-nickel steels as well as ferritic chromium steels assume a transpassive state under such service conditions, and suffer from intergranular attack even if the structure is free of precipitates. A significant corrosion resistance to highly concentrated nitric acid in combination with good workability and weldability can be achieved by an austenitic chromium-nickel steel alloyed with silicon. For corrosion considerations a silicon contents of at least 3,7 wt. % has to be aimed at. Since the silicon is held in solid solution in the austenitic matrix, the mechanical properties of the special grade X 2 CrNiSi 18 15 are not very different from those of commercial chromium-nickel steel grades. Welding materials of the same kind are available for manual are welding as well as for TIG welding. The corrosion resultance of the weld deposit is similar to that of the base metal. However, the tendency of this steel to precipitate intermetallic phases is increased by the silicon addition. There, a proper heat control during welding is a necessary prerequisite in order to avoid intercrystalline attack in the heat-affected zones on both sides of the weld. A silicon contents of approximately 4 wt. % not only improves the corrosion resistance against highly concentrated nitric acid but also results in a considerable improvement when this special steel is used in chromic acid solutions and hot concentrated sulfuric acid. Also the high temperature corrosion, resistance of this material is remarkable. Several piping systems, chemical equipment, pumps, and fittings have been in successfull service for several years and proved the excellent properties of the X 2 CrNiSi 18 15 specially steel.     

Entwicklung,Eigenschaften, Verarbeitung und Einsatz des hochsiliciumhaltigen austenitischen Stahls X2CrNiSi1815

Development, Properties, Processing and Applications of High-Silicon Steel Grade X2CrNiSi1815 Production, storage and transportation of highly concentrated nitric acid (approximately 98%) frequently occur in containers and vessels made of pure aluminium. In many cases, however, their service life is restricted by the insufficient corrosion resistance of the welds. Though tantalum exhibits a superior resistance to corrosion, it is only used in very specific occasions for cost considerations. Commercial grade austenitic chromium-nickel steels as well as ferritic chromium steels assume a transpassive state under such service conditions, and suffer from intergranular attack even if the structure is free of precipitates. A significant corrosion resistance to highly concentrated nitric acid in combination with good workability and weldability can be achieved by an austenitic chromium-nickel steel alloyed with silicon. For corrosion considerations a silicon contents of at least 3,7 wt. % has to be aimed at. Since the silicon is held in solid solution in the austenitic matrix, the mechanical properties of the special grade X2CrNiSi 18 15 are not very different from those of commercial chromium-nickel steel grades. Welding materials of the same kind are available for manual arc welding as well as for TIG welding. The corrosion resultance of the weld deposit is similar to that of the base metal. However, the tendency of this steel to precipitate intermetallic phases is increased by the silicon addition. There, a proper heat control during welding is a necessary prerequisite in order to avoid intercrystalline attack in the heat-affected zones on both sides of the weld. A silicon contents of approximately 4 wt. % not only improves the corrosion resistance against highly concentrated nitric acid but also results in a considerable improvement when this special steel is used in chromic acid solutions and hot concentrated sulfuric acid. Also the high temperature corrosion resistance of this material is remarkable. Several piping systems, chemical equipment, pumps, and fittings have been in successfull service for several years and proved the excellent properties of the X 2CrNiSi 18 15 specially steel.     

铝合金汽车发动机缸体内壁表面改性的研究进展

节能减排是汽车制造行业面临的巨大挑战,发动机的轻量化结构设计及性能提升是解决该问题的重要途径之一。铝合金发动机缸体满足轻质要求,但其耐磨损性能较差,容易造成缸体内表面磨损失效,采用表面改性技术对铝合金发动机缸体内壁进行强化是有效的解决途径。相比于传统的铸铁内嵌式缸套,通过微弧氧化、等离子喷涂、电弧喷涂、超音速火焰喷涂等技术在铝合金基体上制备涂层可以极大地改善其耐磨性能,同时降低发动机的整体质量。本文详细阐述了适用于铝合金发动机缸体内表面改性技术的原理、特点及涂层制备等的研究进展,重点探讨了涂层的沉积成形机理及耐磨损机制研究现状,对涂层材料的设计及优化、涂层制备工艺参数的精细化调控及涂层设备的开发及改进等方面进行了展望。     

Influence of coating on short steel fiber reinforcements on corrosion behavior of aluminium base short steel fiber reinforced composites

Steel fiber reinforced aluminium composites are attractive materials of high specific strength but exhibit poor resistance against electrochemical corrosion. The study discusses the electrochemical corrosion behavior of uncoated, copper and nickel coated short steel fiber reinforced aluminium and Al–2Mg matrix composites in 1 (N) NaCl solution. Galvanic corrosion between the steel fiber and aluminium governs the corrosion behavior of these composites. It has been observed that open circuit potential (OCP) is shifted to more negative side with copper coating on the fibers and to the more positive side on coating the fibers with nickel. Compared to the uncoated fiber higher corrosion current density indicates corrosion rate was observed for the copper coated fiber reinforced composites where as a lower current density was noted for the nickel coated fiber reinforced composites was observed. Addition of 2 wt% magnesium to aluminium alloy matrix increased the corrosion current density. The corrosion mechanism in these composites is dominated by galvanic cell formation that is evident from the dissolution of Al matrix near the peripheral region of steel fibers.     

SiO2粒径对Ni-Co-SiO2复合镀层性能的影响

长期暴露在海洋环境中的钢质紧固件的腐蚀问题严重影响了海洋工程装备和设施的服役安全性。电镀合金镀层是紧固件常用的防护方法,其中,镍钴合金镀层具有较好的耐蚀性。通过向Ni-Co镀液中添加不同粒径的SiO₂颗粒,利用电沉积技术在45钢基体上制备Ni-Co-SiO₂复合镀层。之后,分析了SiO₂粒径对复合镀层表面形貌和显微结构的影响,评价了复合镀层在3.5%（w）的NaCl溶液中的耐蚀性能,并对复合镀层的显微硬度和摩擦系数进行了测试。结果表明,随着镀液中SiO₂粒径的增大,复合镀层表面的SiO₂分布均匀性先增大后减小,当SiO₂粒径为70 nm时,镀层表面形成较完整的SiO₂膜层。动电位极化和电化学阻抗谱测试表明,掺杂70 nm的SiO₂的复合镀层具有最好的耐蚀性。随着镀液中SiO₂粒径增大,复合镀层的硬度逐渐降低,但其对摩擦系数的影响较小。      

全光亮和高耐蚀性非晶态合金层的制备新工艺

光亮和耐蚀性在金属镀层的应用中起着极其重要的作用。本研究是在普通碳素钢表面制备全光亮和高耐蚀性非晶态合金层的方法，其主要特点是化学镀溶液中不需加入任何光亮剂、整平剂、应力消除剂和润湿剂，就能从镀液中直接镀制出全光亮的非晶态合金层，在硫酸、盐酸、磷酸、氢氧化钠和氯化钠等强酸碱盐腐蚀介质中全浸腐蚀48小时，非晶态合金层具有很高的光亮度，不会变色。在空气中长期放置，非晶态合金层仍保持光亮性。另外，在酸性腐蚀介质中，非晶态合金层能使基体Q235钢的耐蚀性提高38倍以上，达到并超过1Cr18Ni9Ti不锈钢。     

激光熔覆CoCrFeMnNiMox高熵合金的组织和耐蚀性研究

目的 为了增强钢制结构表面的耐蚀性,研究Mo含量对CoCrFeMnNiMox高熵合金组织与耐蚀性的影响。方法 采用激光熔覆的方式在N80钢上制备CoCrFeMnNiMox（x=0.1、0.2、0.3、0.4、0.5）高熵合金熔覆层,研究Mo含量变化对高熵合金组织、物相与耐蚀性的影响。结果 CoCrFeMnNiMox熔覆试样均由单一的FCC固溶体相组成,随着Mo含量的增加,晶格畸变增大;当Mo的摩尔比超过0.3后,晶粒有长大倾向;Mo的摩尔比为0.5时,表面择优生长晶面由（111）密排晶面转变为（200）非密排晶面。熔覆试样在氯化钠溶液和稀硫酸溶液中的耐蚀性相较N80钢提升明显,其中,CoCrMnFeNiMo0.3的耐蚀性最好,在质量分数为3.5%的氯化钠溶液中其自腐蚀电流密度是N80钢的5%,自腐蚀电位比N80钢提高了1倍;在0.5 mol/L硫酸溶液中,其自腐蚀电流密度是N80钢的31%,钝化区电流密度比N80钢降低了1个数量级。结论 在该高熵合金体系中,随着Mo含量的增加,晶格畸变增大。CoCrMnFeNiMox高熵合金熔覆层可以有效地阻止基体腐蚀的发生。Mo元素在溶液中能够形成MoO3附着在金属表面,从而形成稳定致密的保护层,减少点蚀的发生。CoCrMnFeNiMo0.3熔覆层的耐蚀性最好。     

土壤盐浓差对碳钢/铝合金电偶腐蚀行为影响

利用砂土作为模拟土壤 ,通过失重法及电化学方法相结合 ,研究了土壤盐浓差( 2 0 %Cl-及 0 2 %Cl-)对A3钢 LC4铝合金电偶腐蚀的影响规律。结果表明 ,其电偶腐蚀主要取决于电偶对阴极A3钢所处的土壤条件 ,而与电偶对阳极所处的土壤条件关系不大。电偶对阴极处在高盐土壤中 ,其阴极保护效率较高 ,电偶对阳极LC4铝合金与同样试验条件下自然腐蚀相比 ,其腐蚀速率最大增加了 145倍。     

Al-Zn coatings for the corrosion protection of steel

Aluminum coatings have been reported to be the most suitable for replacing toxic cadmium for the protection of steel and titanium alloys against corrosion. The relatively poor galvanic corrosion protection of aluminium coatings, however, has led to a search for a more effective coating. To this end, pure aluminium and controlled-composition Al-Zn alloy coatings were ion plated onto steel substrates. Over a range of coating conditions the aluminium and the Al-Zn alloy coatings have very similar columnar structures. They were equally successful in protecting the underlying steel. However, a simulation of the coating damage by masking the steel substrate during plating showed the galvanic corrosion protection of Al-2.5%Zn alloy coatings to be superior to that of aluminium. It is probable that this very effective sacrificial corrosion protection means that the structure of the coating is relatively unimportant and that excellent galvanic corrosion protection can be provided by low density columnar structure coatings of Al-Zn alloys.     

管腔内支架用金属材料的生物相容性及其表面改性

管腔内金属支架是用于植入人体各管道狭窄处起支撑作用的医疗器械,因其与人体组织直接接触,故对支架的生物相容性的研究十分重要。本文对用于管腔内支架的３１６Ｌ不锈钢和ＮｉＴｉ合金的耐腐蚀性和生物相容性进行了综合评述;并以冠状动脉支架为应用背景,着重分析了影响血管内支架血液相容性的因素,提出了对支架进行表面改性处理以提高其血液相容性的技术路线。     

Metallurgical aspects of corrosion

Metallurgical properties have strong effects on corrosion. The paper discusses and reviews the work done at CECRI on the metallurgical aspects of corrosion of some industrially important alloys like steel and aluminium alloy weldments, stainless maraging steel and prestressing steel. The corrosion control methods for the above materials are also reviewed.     

Korrosionsinhibierende Plasmapolymerschichten auf Stahluntergründen

Plasma polymeric coatings with inhibitory effect on steel surfaces The plasma based surface technique facilitates scientifically and technically, economically and ecologically interesting alternatives to traditional treatment procedures. From that the evolution of a new procedure for the improvement of the corrosion resistance of low‐alloy steel surfaces through ultrathin plasma polymeric coatings was a main topic at the iLF in the last years. After plasma based super cleaning process under oxidized conditions should be produced plasma polymeric coatings with a corrosion inhibiting / passivation effect. For this purpose corrosion inhibitor molecules are implanted into the normally electrochemically inactive coating during the process of the plasma based polymerization of silicon‐organic monomers. Through that it has been proved that the long‐term corrosion protection improves. Besides the surface of the produced plasma polymer shift can be modified by plasma‐technical procedures so that it shows also optimal adhesion promoter characteristics.     

Inverse Approach to the Forming Simulation of Tailored Heat Treated Blanks

While climate protection and environmental conservation gain an increasingly significant role, the weight reduction of car body parts is a consequence of the need for efficient fuel consumption and for reduced CO2-emissions. Therefore advanced material and production methods have to be developed to meet this requirement. Since steel sheet metal parts cannot be substituted directly with lightweight aluminium parts, due to its minor formability, so called Tailored Heat Treated Blanks (THTB) are presented in this work. THTB are locally heat treated aluminium blanks from the 6000-series alloy, leading to a significantly improved formability for the manufacturing of complex aluminium car body parts. The enhancement of formability is reached by a local laser heat treatment before the forming operation. Since there is a strong influence of the heating on the forming process, a finite-element simulation of the process sequence is a prerequisite for the cost-effective usage of the THTB. The presented inverse approach considers first the desired forming result and enables the precise determination of heat treatment areas including the specific heat treatment temperatures. In conclusion the numerical solved appropriate strength pattern is verified with experimental test results of THTB.     

电解液对ZL101铝合金微弧氧化膜层性能的影响

为了提高铸铝合金的使用寿命,在接触网ZL101A铸铝合金件上制备了微弧氧化膜层,并采用扫描电镜(SEM)、X射线衍射仪(XRD)、摩擦磨损试验、电化学试验等,研究了不同电解液对微弧氧化膜层性能的影响。结果表明:电解液为硅酸盐时,膜层有较好的耐磨性和耐腐蚀性。     

钢芯铝绞线钢芯表面植酸活化对化学镀Ni-P层耐蚀性的效用

为了提高钢芯铝绞线钢芯的耐蚀性,采用植酸对其活化再化学镀覆Ni-P合金,研究了植酸活化处理对钢芯钢表面Ni-P镀层耐蚀性的影响。采用SEM和EDS对Ni-P镀层腐蚀前后的形貌和成分进行了分析,在1mol/L H_2SO_4+3%NaCl混合溶液中测定了其极化曲线,比较了其腐蚀速率;利用超声波振荡法研究了植酸活化前后Ni-P镀层与基体的结合力。结果表明:钢芯表面经植酸活化后Ni-P镀层的胞状凸起细小,结构更加均匀、致密,与基体有较好的结合力;植酸活化后,Ni-P镀层的腐蚀电位变大,腐蚀电流减小,腐蚀9 h时Ni-P镀层表面几乎无变化。     

Laurus nobilis L. oil as green corrosion inhibitor for aluminium and AA5754 aluminium alloy in 3% NaCl solution

The influence of (30%, v/v) ethanolic solution of Laurus nobilis L. oil on the corrosion inhibition of aluminium and AA5754 aluminium alloy in 3% NaCl solution was studied by weight loss method, potentiodynamic polarization, and linear polarization method. The polarization measurements show that addition of this oil in concentrations ranging from 10 ppm to 50 ppm induces a decrease of cathodic currents densities. The results confirm that AA5754 alloy has better corrosion resistance in 3% NaCl solution than pure aluminium, while the oil investigated has better inhibition action on corrosion process of pure aluminium. The surface analysis via SEM techniques indicate that the active molecules from L. nobilis L. oil absolutely retard the pitting corrosion on the specimen surfaces.     

AZ31镁合金表面气相沉积不锈钢薄膜的实验研究

利用真空蒸发镀膜技术在镁合金表面沉积不锈钢薄膜是提高镁合金防腐性能的新尝试.本研究利用该技术在AZ31上成功制备了不锈钢薄膜.通过在5%NaCl溶液中的浸入实验和极化实验考察了腐蚀性能,发现镀膜后耐蚀性显著降低.另外,镀膜后的显微硬度也未有明显提高.利用AFM,SEM,EDX等分析手段对薄膜进行了观察和检测,发现耐蚀性变差的原因主要是薄膜表面存在贯穿性的微米级孔洞和Cr元素分布不均匀造成的.     

缓蚀型添加剂对阳极氧化后铝合金耐蚀性的影响

选择海洋用铝合金进行阳极氧化处理,运用电化学极化及交流阻抗技术,结合微观分析,比较阳极氧化后铝合金的耐蚀性。结果表明,所研究的铝合金中主要存在Al-Cu-Mn-Fe-Si-Cr和Al-Mg-Si第二相,Al-Cu-Mn-Fe-Si-Cr相不溶解,在氧化膜中呈突起状态;而Al-Mg-Si相溶解形成孔洞,易受到侵蚀,成为腐蚀源。对于特定的铝合金,阳极氧化电解液中添加Na2MoO4缓蚀剂后,MoO4^2-进入阳极氧化膜,抑制侵蚀性离子的有害作用,提高了铝合金的耐蚀性。     

海洋环境下热喷涂锌、铝及其合金涂层防腐蚀机理研究概况

综述了国内外几十年来在不同海水环境中对热喷涂锌铝及其合金涂层防护性能和机理研究的成果.热喷涂锌铝及其合金涂层在海洋环境中具有优良的长效防护性能,锌具有优良的电化学保护性,铝具有比锌更好的化学稳定性,锌铝合金既保留了锌的电化学特点,又具有铝的化学稳定性能.指出了今后的研究重点应该是金属与有机复合层在浪花飞溅区苛刻腐蚀环境下界面的腐蚀规律和腐蚀机理的探讨,对金属与有机复合层界面的腐蚀原因在理论上做出了本质的解释,并能预测涂层体系的防腐蚀寿命.     

Microstructure modifications and corrosion behaviors of Cr4Mo4V steel treated by high current pulsed electron beam

In this work, Cr4Mo4V steel was irradiated by high energy current pulsed electron beam (HCPEB) with energy density of 6 J/cm². Morphology and phase composition of the surface layer were analyzed using scanning electron microscopy (SEM) and glancing angle X-ray diffraction (GXRD). The crater-like morphology was observed on surface after HCPEB treatment, and the thickness of melted layer was ∼7 μm. Results from GXRD revealed that HCPEB treatment could suppress martensite transition and the content of retained austenite in the melted layer increased with irradiation number. The corrosion resistance was evaluated by electrochemical polarization tests in neutral 3.5% NaCl solution. Compared with the untreated Cr4Mo4V steel, corrosion potential of the samples treated by HCPEB improved and the corrosion current density decreased. The improved corrosion resistance is attributed to the absence of the carbide, formation of retained austenite and dissolution of alloy elements, particularly of Cr and Mo, into the matrix.