Lepera试剂.doc

LePeras reagent所谓Lepera试剂（Le Pera ）就是：偏重亚硫酸钠溶液和苦味酸溶液的混合液，其组成为10 g/L的偏重亚硫酸钠的水溶液，与40 g/L的苦味酸的乙醇溶液按11混合。一般侵蚀130秒（a solution of 1 g sodium metabisulfite in 100 water mixed with 4 g of picric acid dissolved in 100 of water, for 1-30 sec (LePERA, 1979; Lawson et al., 1980)）。（此段文字的来源，当时没有记录，现在反复寻找，没有结果）Lepera试剂在ASM的手册（9）中没有体现，检索无结果；比较令人意外。因为国内TRIP钢的研究涉及Lepera试剂的较多，在ASM的手册（9）中，TRIP钢所使用的试剂是：2% nital etch、4% picral etch。在下面这篇文章（作者：Y Sakuma - 1991 - 被引用次数：98）中，有一篇参考文献，26，Metallurgical and Materials Transactions A Volume 22, Number 2, 489-498, 1991Mechanical properties and retained austenite in intercritically heat-treated bainite-transformed steel and their variation with Si and Mn additions Yasuharu Sakuma, Osamu Matsumura and Hiroshi Takechi26 S. Bandoh, O. Matsumura, and Y. Sakuma: Trans. Iron Steel Inst. Jpn., 1988, vol. 28, pp. 569-74.文章中涉及26的说：Optical microscopy measurements were made on the specimens prepared by the tint-etching method, with a solution of 4 pct HNO3 + 7 pct (NO2)3CtH2OH + saturated Na2S203, 26。 在下面这篇文章（作者：E Girault - 1998 - 被引用次数：89）中，有部分源自F.S. LePera的文章中的描述；在得不到原文的情况下，看看最基本的内容也不错。Materials CharacterizationVolume 40, Issue 2, February 1998, Pages 111-118Metallographic Methods for Revealing the Multiphase Microstructure of TRIP-Assisted SteelsE. Girault, P. Jacques, Ph. Harlet, K. Mols, J. Van Humbeeck, E. Aernoudt and F. Delannay 在韩波的贝氏体钢彩色金相研究中的参考文献，也提到了这篇文章，不过，书写的“刊物”、“页数”有关信息较为奇怪：1 Girault E, Jacques P, Harlet P, et al. Metallographic methods for revea ling the multiphase microstructure of TRIP-assisted steels J. Elsevier Science, 1998, 40（2）：111-112. 邹宏辉的Si-Mn系TRIP钢显微组织研究中将此文作为参考文献时是正确的；微有瑕疵的是：没有标注“期数”。4 Girault E, Jacques P, et al. Metallographic methods for revealing the multiphase microstructure of TRIP-assisted steelsJ. Materials Characterization. 1998,40:111118.贝氏体钢彩色金相研究中还有一个参考文献比较奇怪，这篇文章并没有提到有关LePera reagent的有关信息；而作为参考文献的目的何在，令人疑惑。就是： 2 张珣. 彩色金相在电力系统的应用 J . 安徽电力职工大学学报,2002, 7 (1) : 122.F.S. LePera首创的试剂，似乎有2个文献来源，请看下面的检索：Improved etching technique for the determination of percent martensite in high-strength dual-phase steels Metallography Volume 12, Issue 3, September 1979, Pages 263-268F.S. LePeraAbstractAn improved metallographic etchant and technique for delineating the various constituents in high-strength dual-phase steels has been developed as a result of the need for increased contrast when using electronic image analysis equipment. With an etchant consisting of a 1% aqueous solution of sodium metabisulfite (Na2S2O5) and 4% picric acid (C6H2(NO2)3OH) in ethyl alcohol, martensitic grains appear white, bainite appears black, ferrite appears tan, and in most cases, the grain boundaries are not strongly etched. Consequently, accurate measurements of the amount of martensite and bainite can be made using electronic image analysis equipment.Improved Etching Technique to Emphasize Martensite and Bainite in High-Strength Dual-Phase SteelLePera, F SJ. Met. Vol. 32, No. 3, pp. 38-39. Mar. 1980Many etchants based on sodium metabisulfite were tried in National Steels Research Laboratory on Cr-bearing dual-phase steels, but most failed to differentiate martensite from bainite. However, excellent results were obtained from a mixture of 1% sodium metabisulfite (Na2S2O5) in distilled water and 4% picric acid C6H2(NO)3OH in ethyl alcohol (either specially denatured alcohol S.D.A. 32, or completely denatured alcohol S.D.A. 1) in a 1:1 volume ratio. With this etchant, martensite appears white, bainite appears black, ferrite appears tan, and, in most cases, grain boundaries are not strongly etched.-AAImproved Etching Technique to Emphasize Martensite and Bainite in High-Strength Dual-Phase Steel里面的段落（源自Metallographic Methods for Revealing the Multiphase Microstructure of TRIP-Assisted Steels）：The specimen is embedded in an acrylic resin that stiffens at room temperature. The classical grinding and polishing stages are performed at least down to the use of 1m diamond paste. It is essential that the sample be freshly polished before etching to prevent any risk of preoxidation of the surface. After the last sequence of polishing, the specimen is rinsed with distilled water, cleaned with a soapy-water-soaked cloth, rinsed again, and flushed with ethanol. It is then dried under a warm air flow. This operation must be repeated several times to eliminate any trace of lubricant or impurities from the last polishing step.The etchant is a mixture of two pristine solutions whose compositions are given in Table 2. Volumes of 30 2 ml of reagent 1 and 30 2 ml of reagent 2 are poured into two different beakers. Just before the etching is started, the solutions are mixed in a small crystallizing vessel. The specimen is held vertically with a small tong and immediately immersed in the mix. It is given a permanent oscillation during the whole etching time, which lasts between 10 and 20 s, depending on the steel composition. After etching, the specimen surface is immediately flushed with ethanol and blown dry under a cool air flow. This step is repeated a few times to ensure that no etchant remains on the specimen. The specimen is finally observed with a microscope equipped with a high-brightness halogen lamp.Table 2 Composition of the SolutionsReagent 1 Reagent 21 g Na2S2O5 4g dry picric acid100 mL distilled H2O 100mL ethanol邹宏辉的Si-Mn系TRIP钢显微组织研究中，有改进的LePera reagent。表3腐蚀剂中两种溶液的浓度试剂适用试样溶质溶剂1A、C1g Na2S2O580mL蒸馏水2B1g Na2S2O560mL蒸馏水3A、B、C1g苦味酸(干燥)40mL乙醇腐蚀剂的配制根据试样化学成分,按表3配制偏重亚硫酸钠溶液和苦味酸溶液。腐蚀时,将偏重亚硫酸钠溶液和苦味酸溶液混合(A、C钢需将溶液1和溶液3混合,B钢将溶液2与溶液3混合),体积比为11,搅拌均匀。然后将试样浸入腐蚀液中侵蚀1824s,使腐蚀面泛出蓝橙般的光泽。 超高强度船体钢中马氏体/奥氏体的演变一文，对于LePera试剂的着色效果，也有比较感性的介绍。在Y. D. PARK的Retained Austenite as a Hydrogen Trap in Steel Welds中，提到LePeras reagent时说：Specimens for optical microscopy were prepared by mechanical polishing through 0.05-m alumina. Super duplex stainless steels were electrolytically etched for 5 to 20 s with 10% oxalic acid. LePeras reagent (Refs. 7, 8) was used to etch the HSLA steel weld deposits for optical microscopy. This etching method is based on sodium metabisulfite mixed with picric acid. The retained austenite and untempered martensite (or MA constituent) was identified with contrast enhancement resulting from LePeras reagent, which was a fresh solution of 4% picric acid in ethanol mixed with a 1% solution of sodium metabisulfite in distilled water in a 1:2 volume ratio.7. Iino, M. 1998. Evaluation of hydrogentrap binding enthalpy II. Met. Tr a n s . 2 9 A : 10171021.8. Le Pera, F. S. 1980. Improved etching technique to emphasize martensite and bainite in high-strength dual-phase steel. J. Met. 32(3): 3839.因此，两种基础试剂的混合配置配置比例也有不同的理解（常见识1：1）。关于：modified LePera reagent，在METAL 2009 19. 21. 5. 2009, Hradec nad Moravic，上的Katarna Burikov，Gejza Rosenberg的文章QUANTIFICATION OF MICROSTRUCTURAL PARAMETER FERRITIC-MARTENSITE DUAL PHASE STEEL BY IMAGE ANALYSIS中，终于涉及到了S. Bandoh的“modified LePera reagent”。同时，有了S. Bandoh完整的文献名称：8 Bandoh, S., Matsumura, O., Sakuma, Y.: An improved tint etching method for high strength steel sheets with mixed microstructures. Transactions ISIJ, 1988, Vol. 28, p. 569-574, Bandoh侵蚀剂配置：Solution A: 7 g Na2S2O5, 100 ml H2OSolution B: 5 g picric acid,100 ml C2H5OHSolution C: 4 ml HNO3, 95 ml C2H5OHFerrite is blue, martensiteand austenite is yellow,bainit is brown后来，又检索到S. Bandoh的文章的Abstract：An improved tint etching method was developed to obtain a quantitative measure of the microstructure of high strength steel sheets with a mixed structure. The procedures of etching are presented with typical examples. The present method reveals ferrite in blue, martensite and retained austenite in light yellow, and bainite in brown. Each constituent is identified by electron microscopic observations of the same area on etched microstructure. The different colors are analyzed to be a result of difference in the thickness of etched films by means of Auger spectroscopy. The new method is combined with image analysis to determine quantitatively the fraction and morphology of microconstituents.Keywords:metallography, optical microscopy, etching method, cold-rolled steel, composite structure（Transactions of the Iron and Steel Institute of Japan；Vol.28 , No.7(1988)pp.569-574）（S. Bandoh, O. Matsumura and Y. Sakuma: Trans. Iron Steel Inst. Jpn., 28 (1988), 569）关于“The LePera techniques”查阅到的最为详细的介绍是：FUNDAMENTAL STUDY OF PHASE TRANSFORMATIONS IN Si-Al TRIP STEELS（很幸运，有下载的地址：/ETD/available/etd-