非晶态Fe80B20合金晶化产物研究

利用Ｘ射线衍射及透射电子显微镜等手段研究了非晶态Ｆｅ８０Ｂ２０合金的晶化产物结构与热处理温度的关系，发现在不同退火温度下晶化产物均由α－Ｆｅ（Ｂ）固溶体和Ｆｅ－Ｂ化合物组成；α－Ｆｅ（Ｂ）固溶体的相对含量随退火温度的高而增多；化合物有Ｆｅ３Ｂ和Ｆｅ３．５Ｂ两种，它们的相对含量与退火温度密切相关且表现现不同程度的晶格畸变。     

非晶态Fe_（80）B_（20）合金晶化产物研究

利用Ｘ射线衍射及透射电子显微镜等手段研究了非晶态Ｆｅ_（８０）Ｂ_（２０）合金的晶化产物结构与热处理温度的关系，发现在不同退火温度下晶化产物均由α－Ｆｅ（Ｂ）固溶体和Ｆｅ－Ｂ化合物组成；α－Ｆｅ（Ｂ）固溶体的相对含量随退火温度的升高而增多；化合物有Ｆｅ_３Ｂ和Ｆｅ_（３．５）Ｂ两种，它们的相对含量与退火温度密切相关且表现出不同程度的晶格畸变．     

稀土永磁材料的最近进展（一）

综述了Ｒ２Ｆｅ１４Ｃ系金属间化合物的研究进展概况，包括Ｒ２Ｆｅ１４Ｃ系化合物的制备和晶体结构，它们的磁化强度、居里温度和磁晶各向异性。与Ｒ２Ｆｅ１４Ｂ系化合物对比，阐明了Ｒ２Ｆｅ１４Ｃ化合物作为永磁材料的可能性和特点。     

HD和HDDR方法对稀土铁基化合物磁特性的影响

系统介绍了ＨＤ和ＨＤＤＲ方法对稀土铁基化合物Ｎｄ２Ｆｅ１４Ｂ和Ｓｍ２Ｆｅ１７磁特性的影响，指出ＨＤ方法可以用于ＮｄＦｅＢ永磁材料生产的中间破碎过程。ＨＤＤＲ方法能够制备ＮｄＦｅＢ各向异性永磁粉末，它是目前通用的制备方法所不能达到的，Ｓｍ２Ｆｅ１７Ｎ３－δ化合物制备中，ＨＤＤＲ方法是渗Ｎ的先期准备过程。     

Nd2（Fe,Co）14B／Nd2（Fe,Co）17双相HDDR磁粉的微观结构和磁特性

研究了由Ｎｄ２（Ｆｅ，Ｃｏ）１４Ｂ和Ｎｄ（Ｆｅ，Ｃｏ）１７双相组成的ＨＤＤＲ高矫无力磁粉的微以结构及磁性。发现在单相Ｎｄ２（Ｆｅ，Ｃｏ）１４Ｂ化合物的基础上降低Ｂ含量，导致Ｎｄ２（Ｆｅ，Ｃｏ）１７相出现，且随Ｂ含量随低该相逐渐增多。     

硬磁材料的发展

硬磁材料的发展随着电子技术的迅速发展，对高性能永磁材料的需求日益增加。现在以Ｓｉｎ－Ｃｏ和Ｎｄ—Ｆｅ－Ｂ为代表的稀土磁体形成了永磁材料市场的主流。Ｎｄ－Ｆｅ－Ｂ以ＮｄｚＦｅ；。Ｂ正方晶化合物为主相的永磁体，其最大磁能积已由当初的３５ＭＧＯｅ提高到了４...     

耐液态锌腐蚀材料的研究和应用

研究了多种材料的耐液态锌腐蚀性能，筛选出实用性较好的改性Ｆｅ－８金属间化合物，带有这种Ｆｅ－Ｂ化合物层的热电偶套管在工业上试用，取得了良好的效果。     

Sm-Fe-N αFe系纳米复合磁体

纳米复合磁体是由纳米级晶粒的永磁相和软磁相两相复合的材料,作为永磁相是Ｎｄ２Ｆ１４Ｂ化合物而软磁相为Ｆｅ３Ｂ化合物,但其矫顽力最高仅为６１０ｋＡ／ｍ。为进一步提高这种材料的磁性能,日本ＴＤＫ公司新近开发成功矫顽力高达７６０ｋＡ／ｍ的复合磁体,它采用了Ｓｍ－Ｆｅ－Ｎ系化合物取代Ｎｄ２Ｆｅ１４Ｂ,而用具有更高磁化强度的α－Ｆｅ作为软磁相取代Ｆｅ３Ｂ。在制造过程中,为了使Ｓｍ－Ｆｅ合金的晶粒微细化而在其成分中添加了Ｚｒ（其原子半径居于Ｓｍ和Ｆｅ之中间位置）。在制造磁体成分为（Ｓｍ８Ｚｒ３Ｆｅ８５Ｃｏ４…     

生产Nd－Fe－B永磁合金粉末的HDDR法

生产Ｎｄ－Ｆｅ－Ｂ永磁合金粉末的ＨＤＤＲ法Ｎｄ－Ｆｅ－Ｂ系磁体的主相是强磁性的Ｎｄ２Ｆｅ１４Ｂ金属间化合物。该Ｎｄ２Ｆｅ１４Ｂ在室温～６５０℃氢气氛中形成氢化物Ｎｄ２Ｆｅ１４ＢＨｘ，并引起吸氢爆裂。此现象被称之为ＨＤ（氢化爆裂）现象。可把这种现象利用...     

稀土类硬磁材料

最初的稀土类硬磁材料是６０年代开发的Ｓｍ－Ｃｏ系磁体,后来又开发了Ｎｄ－Ｆｅ－Ｂ系及Ｓｍ－Ｆｅ－Ｂ系新磁体,使磁体的最大能积获得飞跃性提高．由于它价格高,所以并不能完全取代铁磁体,但随着工业制品小型化的需要,稀土类磁体已应用到各个领域． １９８３年日本佐川等人发现了Ｎｄ、Ｆｅ、Ｂ三元化合物,其居里温度高,并开发出最大能积为２９０ｋＪ／ｍ３的Ｎｄ－Ｆｅ－Ｂ系烧结磁体．其主相为Ｎｄ２Ｆｅ１４Ｂ化合物,钕和硼仅存在于ｃ面和１／２ｃ面,铁在其中以类似σ相构造存在,除钦外的稀土元素Ｒ可形成Ｒ２Ｆｅ１４Ｂ化…     

粘结底层材料的耐锌蚀性能研究

用等离子喷涂技术制备了用作粘结底层的Al/Ni、Fe-Al涂层,研究对比了这两种涂层在锌液中的耐腐蚀性能。结果表明,Fe-Al比Al/Ni有更好的耐锌蚀性。     

Effect of Nano-oxide addition on corrosion performance of hot dip zinc coating

Corrosion performance of hot dipped zinc coating on low carbon steel was studied at the presence of different nanoand micronsize oxide particles in the liquid zinc bath. Nano-silica, nano-alumina and micro-alumina powders were loaded to the different liquid baths, in the range of 0.05–0.2 wt %. Low carbon steel specimens were immersed in the baths for a constant time of 10s. It was evident that the presence of oxide particles in the liquid bath increased the coating thickness at a constant immersing time; micro-alumina particles provided the thickest coating among the others. Salt spray and potentiodynamic polarization tests were conducted to evaluate corrosion performance of the galvanized coatings, including oxide bearing ones. The results confirmed improvement in corrosion resistance of the nano-oxide bearing zinc coatings; while incorporation of micro-alumina in the bath declined its corrosion resistance. It was shown that incorporation of nano-silica powder in the liquid bath yielded superior corrosion resistance of the zinc layer, in comparison to the other ones. The optimum corrosion performance of zinc coating was achieved via loading 0.1 wt % nanosilica to the liquid zinc bath in this work.     

沉没辊基础件的熔融锌液腐蚀研究现状

根据近些年国内外耐锌腐蚀的研究成果,将耐锌腐蚀方法分为两大类:自身耐锌腐蚀材料和表面改性处理。自身耐锌腐蚀材料主要集中在Fe-Cr-Mn、Fe-B、Ti Al Nb等材料上,表面处理主要集中在WC-Co、Mo B-Co Cr、陶瓷等涂层上。两种方法都获得一定的研究成果,但也有一些不足。自身耐锌腐蚀材料的耐熔锌腐蚀虽有改善,但在液锌中也只是延缓了腐蚀速度,最终仍然会腐蚀失效。表面涂层耐蚀性相对较好,但是在锌液中仍然会发生裂纹腐蚀,并且涂层和基体之间的物理匹配性较差,脆性较大,工件的轻微碰撞很容易造成涂层的脱落,加速工件的腐蚀,不宜用于实际生产。充分利用陶瓷耐腐蚀、耐高温、硬度高的优点,以及金属室温强度好、延展性好的优点,开发陶瓷金属复合涂层,可能会成为下一步沉没辊基础件熔融锌液腐蚀研究的主要方向。     

Interface characteristics and corrosion behaviour of oriented bulk Fe2B alloy in liquid zinc

The interface characteristics and corrosion behaviour of oriented Fe₂B in liquid zinc have been investigated. The results indicate that Fe₂B with preferential growth direction parallel to corrosion interface displays better corrosion resistance to liquid zinc. The Fe₂B/FeB phase transition occurs due to gradient of chemical potential in solid Fe₂B–liuqid zinc system. The liquid zinc corrosion is competition process of dissolution, Fe₂B/FeB transition and fracture–spalling. The fracture–spalling dominates corrosion process when preferred direction of Fe₂B is perpendicular to corrosion interface while Fe₂B/FeB transition plays a role in liquid zinc corrosion as preferred direction of Fe₂B is parallel to corrosion interface.     

Interfacial morphology and corrosion resistance of Fe–B cast steel containing chromium and nickel in liquid zinc

The interfacial morphology and corrosion resistance of low carbon Fe–B cast steels in zinc bath at 520 °C were investigated. The results show Fe–B cast steel containing high Cr and Ni exhibits the best corrosion resistance to liquid zinc. The corrosion layers are composed of Γ-Fe₃Zn₁₀, δ-FeZn₁₀, ξ-FeZn₁₃ and η-Zn. The corrosion behaviour of Fe–B cast steels includes the following processes: the preferential leach and dissolution of Cr and Ni, the formation of Fe–Zn compounds controlled by zinc atom diffusion, and the spalling of borides without the supporting role of α-(Fe, Cr) matrix corroded by liquid zinc.     

Influences of Si on corrosion of Fe–B alloy in liquid zinc

Abstract

Influences of silicon content on the microstructure and corrosion resistance of a Fe–2·5 wt-%B alloy have been investigated by using scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. Si can change the microstructure from hypereutectic to eutectic and furthermore, enhance the corrosion resistance of the alloy in molten zinc. The high corrosion resistance of the alloy was mainly attributed to the eutectic phase increase and solubility of Si in α phase enhancement. The corrosion of these alloys in liquid zinc was controlled by the diffusion mechanism. The reaction products are FeZn_6·67, Fe₅SiB₂ and FeSi. The reaction layer further prevents the diffusion of zinc atoms into the base material and delays the reaction between the substrate and the molten zinc efficiently.     

316L不锈钢表面激光熔覆钴基合金组织及锌蚀机理

采用半导体激光器在316L不锈钢表面制备钴基合金熔覆层,对激光熔覆层的组织形貌、成分、结构及锌蚀机理进行了系统研究.结果表明,选择优化的激光辐照工艺参数,获得的钴基合金熔覆层表面平整、无裂纹、与基材呈良好的冶金结合.钴基合金熔覆层主要由γ-Co,M₂₃C₆及耐腐蚀性能优异的Laves相Co₃Mo₂Si和少量硬质耐磨相Co₆W₆C组成.在460℃熔融锌中腐蚀试验表明,钴基合金熔覆层的锌蚀机理为选择性腐蚀,熔覆层表层出现一层亮白色腐蚀过渡层,在过渡层内钴基固溶体基体优先发生腐蚀,导致Laves相剥落,从而形成了锌液对钴基合金熔覆层的进一步腐蚀.     

Suppression of liquid metal embrittlement in resistance spot welding of TRIP steel

ABSTRACT

Third-generation advanced high strength steels are typically given a zinc coating that provides excellent resistance to corrosion. During the resistance spot welding process, the melted zinc coating enables liquid metal embrittlement (LME) that causes cracking in the weld indent. In this study, LME in TRIP 1100 and TRIP 1200 steels was suppressed by placing aluminium interlayers added between the electrode and steel contact surface. Compared to welds exhibiting LME, TRIP 1100 with aluminium interlayers showed complete strength recovery while TRIP 1200 with aluminium interlayers resulted in a recovery of strength by 90%. Aluminium interlayers suppress LME by the formation of iron aluminides that hinder liquid zinc from coming in contact with the steel substrate, thus preventing LME.     

Effect of the metallic substrate and zinc layer on the atmospheric corrosion resistance of phosphatized and painted electrogalvanized steels

In this work, the influence of the metallic substrate and zinc layer on the atmospheric corrosion resistance of phosphatized and painted electrogalvanized steels was evaluated. For this purpose two types of electrogalvanized steels were used, one with drawing quality carbon steel as metallic substrate, and the other one with a substrate of Ni–Cu–Cr added carbon steel. The corrosion resistance was determined by accelerated and non‐accelerated corrosion tests, using cyclic test chambers and field tests in industrial and marine atmosphere. The mean corrosion advance and the maximum corrosion penetration of samples were measured using image analysis techniques. The study showed that the substrate and zinc layer mass play a decisive role on the atmospheric corrosion resistance of the phosphatized and painted electrogalvanized steels. It was also verified that it is possible to use smaller zinc layer masses without compromising the corrosion resistance of the material, provided that the metallic substrate has characteristics of atmospheric corrosion resistance, thus contributing to the improvement of the zinc coated steels.     

Corrosion behaviour of stoichiometric Fe3Si alloy in liquid zinc

The corrosion behaviour of stoichiometric Fe₃Si alloy in a liquid zinc bath for 3 and 62 h at 500°C was examined. The corrosion products at the Fe₃Si/liquid zinc interface were investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The corrosion process was controlled by the diffusion of iron and zinc atoms. There were scarcely any silicon atoms diffusing at Fe₃Si/liquid zinc interface from the matrix to liquid zinc. The phase transition process of the stoichiometric Fe₃Si alloy in liquid zinc was Fe₃Si, α, α+ FeSi+δ, FeSi+δ, and the main corrosion products were periodic array of FeSi and δ phase.