2024年4月11日发(作者：)
LePera′s 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1∶1混合。一般侵蚀1~30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, 1991
Mechanical 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 Takechi
[26] 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 Characterization
Volume 40, Issue 2, February 1998, Pages 111-118
Metallographic Methods for Revealing the Multiphase Microstructure of TRIP-Assisted Steels
E. 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
steels[J]. Materials Characterization. 1998,40:111~118.
《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.
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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 263-268
F.S. LePera
Abstract
An 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 (Na
2
S
2
O
5
) and 4% picric acid (C
6
H
2
(NO
2
)
3
OH) 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 Steel
LePera, F S
J. Met. Vol. 32, No. 3, pp. 38-39. Mar. 1980
Many etchants based on sodium metabisulfite were tried in National Steel's 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.--AA
《Improved 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 1
μm
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 Solutions
Reagent 1 Reagent 2
1 g Na2S2O5 4g dry picric acid
100 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。
试剂
1
2
3
表3 腐蚀剂中两种溶液的浓度
溶质
1g Na2S2O5
1g Na2S2O5
1g苦味酸(干燥)
适用试样
A、C
B
A、B、C
溶剂
80mL蒸馏水
60mL蒸馏水
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1∶1,搅拌均匀。然后将试样浸入腐蚀液中侵蚀
18~24s,使腐蚀面泛出蓝橙般的光泽。
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《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LePera’s
reagent时说：
Specimens for optical microscopy were prepared by mechanical polishing through 0.05-μm alumina.
Super duplex stainless steels were electrolytically etched for 5 to 20 s with 10% oxalic acid. LePera’s
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 LePera’s 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 : 1017–1021.
8. Le Pera, F. S. 1980. Improved etching technique to emphasize martensite and bainite in high-strength dual-phase steel. J. Met. 32(3): 38–39.
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 n
ad Moravicí，上的Katarína Buriková，Gejza Rosenberg的文章《QUANTIFICATION OF MICROS
TRUCTURAL PARAMETER FERRITIC-MARTENSITE DUAL PHASE STEEL BY IMAGE ANALY
SIS》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 H2O
Solution B: 5 g picric acid,100 ml C2H5OH
Solution C: 4 ml HNO3, 95 ml C2H5OH
Ferrite is blue, martensite
and 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）
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关于“The LePera techniques”查阅到的最为详细的介绍是：《FUNDAMENTAL STUDY OF PHA
SE TRANSFORMATIONS IN Si-Al TRIP STEELS》（
很幸运，有下载的地址：/ET
D/available/etd-05072003-104824/unrestricted/ChadMParish_MScMSE_Thesis_
）
至此，才知道了modified LePera reagent的来源及细节：
来源于：[172] D Colleluori, "Improved Etching Methods for Quantitative Analysis of HSLA MultiPhase
Steels," Praktische Metallographie/Practical Metallography, V20, 1983, P546-55
LePera
Picral pre-etch, then
Solution A (50ml):1% Na
2
S
2
O
5
in water
Soluton B (50ml):4% picric acid in methanol
Martensite white,Bainite black,Ferrite tan
Modified LePera
Picral pre-etch, then
Solution A (50ml):2% Na
2
S
2
O
5
in water
Solution B (50ml):4% picric acid in ethanol
Martensite white,Bainite black,Ferrite tan
Bandoh
Solution A (23.5ml):7g Na
2
S
2
O
3
100ml water
Solution B (23.5ml):5g picric acid 100ml ethanol
Solution C (3-10ml):4ml nitric acid 96ml ethanol
Ferrite blue,Martensite and austenite yellow,Bainite brown
但是，这篇文章（Improved Etching Methods for Quantitative Analysis of HSLA MultiPhase Steels）的
原文，却始终搜索不到。
此文《炉卷轧机生产高铌X80 管线钢的微观组织与析出的定量分析》的LePera试剂，添加少量洗涤剂，
算是一个经验。
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