Metallographic Etchants

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Metallographic Etchants
CAUTION Safety is very important when etching.
Be sure to wear the
appropriate protective clothing and observe all
Aluminimum alloys High carbon Steel
Brasses and Bronzes Stainless Steel
Cast Iron Tin Alloys
Copper Alloys Zinc Alloys
Low carbon Steel Ceramics
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The most commonly used etchants
Etchant Composition Conc. Conditions Comments
Kalling's No. 1 Distilled waterCuCl2Hydrochloric acidEthanol 33 ml1.5 grams33 ml33 ml Immersion etching at 20 Degrees Celcius For etching martensitic stainless steels. Martensite will be dark and the ferrite will be colored.
Kalling's No. 2 CuCl2Hydrochloric acidEthanol 5 grams100 ml100 ml Immersion etching at 20 Degrees Celcius For etching duplex stainless steels and Ni-Cu alloys and superalloys.
Kellers Etch Distilled waterNitric acidHydrochloric acidHydrofluoric acid 190 ml5 ml3 ml2 ml 10-30 second immersion. Use only Fresh etchant Excellent for aluminum and alloys immersion for 10-20 seconds titanium alloys immersion for 10-20 seconds.
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Etchant Composition Conc. Conditions Comments
Krolls Reagent Distilled waterNitric acidHydrofluoric acid 92 ml6 ml2 ml 15 secs Excellent for titanium and alloys. Swab specimen up to 20 seconds.
Nital EthanolNitric acid 100 ml1-10 ml Seconds to minutes Most common etchant for Fe, carbon and alloys steels and cast iron - Immerse sample up from seconds to minutes Mn-Fe, MnNi, Mn-Cu, Mn-Co alloys immersion up to a few minutes.
Marble's Reagent CuSO4Hydrochloric acidWater 10 grams50 ml50 ml Immerse or swab for 5-60 secs. For etching Ni, Ni-Cu and Ni-Fe alloys and superalloys. Add a few drops of H2SO4 to increase activity.
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Etchant Composition Conc. Conditions Comments
Murakami's K3Fe (N)6 KOH Water 10 grams10 grams100 ml Pre-mix KOH and water Before Adding K3Fe(CN)6 Cr and alloys (use fresh and immerse) iron and steels reveals carbides Mo and alloys uses fresh and immerse Ni-Cu alloys for alpha phases use at 75 Celcius W and alloys use fresh and immerse WC-Co and complex sintered carbides.
Picral Ethano Picric acid 100 ml 2-4 grams Seconds to minutesDo not let etchant crystallize or dry explosive Recommended for microstructures containing ferrite and carbide.
Vilellas Reagent Glycerol HNO3 HCl 45 ml15 ml30 ml Seconds to minutes Good for ferrite-carbide structures (tempered martensite) in iron and steel
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Guide to Acid Concentrations
Acid / Base Specific gravity Concentration
Nitric (HNO3) 1.4 68-70
Hydrofluoric (HF) - 40
Hydrochloric (HCl) - 37-38
Ammonium Hydroxide (NH4OH) - 35
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Specimen and Mount Holders

• Specially Designed Specimen Holders For SEM
• The specimen holders are designed to improve
  productivity and allow one to view more than one
  sample at a time. This saves pump down time, keep
  chamber cleaner and get more work done. All
  mounts are machined from solid aluminum and come
  with spring clips/or setscrews to hold specimens
  securely. All mounts are made to fit onto the
  stage and are designed to fit through all
  standard specimen exchange ports, and have a
  center-threaded port to accept the Adapter Pins
  that fits SEM instrument. Three different types
  of pin adapters, which are threaded and ready to
  screw on to the base of the holders are available.

Adapter A Overall measurement 28mm long x 3.1mm
diameter (step-up portion is 6.25mm L x 4.8mm
diameter), Adapter B Overall measurement 28mm
long x 6mm diameter, Adapter C Overall
measurement 34.5mm long x 16mm diameter All
adapters have a threaded portion 5mm in length.
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Universal SEM Sample Holder To hold almost any
sample from 3mm to 29mm in diameter plus various
odd shaped samples, with the dimensions not
greater than 29mm. The samples are easily
inserted or removed from the holder. The holder
is made from aluminum and is with four removable
sample arms so that it can hold very small
samples as well, and it provides good electrical
contact to the stage. The standard base
measures 48mm x 42mm x 12mm Thick. .
Vertical Mount for Thin Samples Flat Base This
is designed to hold thin samples vertically in
the SEM or any microscope. It is 25mm in diameter
and 10mm thick. Each of the two loader jaws can
hold up to 3mm thick samples. The spring loader
keeps thin samples vertical so that cross
sections can be studied. This holder is very
useful for cross sections of silicon wafers or
multilayer capicators. .
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Multi Pin Holder The Multi Pin Holder is
designed to save time. It accommodates 3 or 5 of
½" dia.(12.5mm) surface, 1/8" dia. (3.1 75910
Specimen Holders For SEM 10-14 mm) pin.
ISI DS 130 and 150 First Stage Sample Mounts It
is 10mm in diameter, 5mm high, copper sample
holder to fit in the first stage of the ISI DS
130 and 150 SEM's. The inner cylinder is height
adjustable so that one can adjust the sample to
the correct working distance.
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Pin Mount Stub Adapters Made from aluminum, used
to adapt 1/8" (3.1mm) pin diameter SEM
stubs. Available in 10, 15, 16mm diameter as
well.
SEM Sample Holder Set For convenience a SEM
Sample Holder Set to fill all needs is available.
The set consists of one universal holder, one
vertical mount holder for thin samples, one 3-pin
and one 5-pin configuration holder with a key for
the set screw all in a finely finished wood box.
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Four-Pin Stub Holder It accommodates four pin
type, up to 12.5 (1/2") surface specimen stubs,
with 1/8" (3.1mm) diameter pin.
Cross Sectional Holder Made from non-magnetic
stainless steel with 3.1mm (1/8") diameter pin
and adjustable angle turn-screw. Just insert
specimens edge-on and observe the cross section
directly
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Five 10mm Stub Holder Accommodates five 10mm
diameter specimen stubs, with 1/8" (3.1mm)
diameter pin
Thin Sample Holder Ideal for examination cross
section of thin samples, such as wafers,
multi-layer of capacitors, plastics, metals, etc.
½" diameter (12.7mm), 1/8" (3.1mm)dia. pin
(3.1mm) with split openings up to ¼" (6.4mm).
Available with either 8mm (5/16") pin height or
15mm (9/16") pin height. For ISI, JEOL, TOPCON
Double set screw for a secure holding of the
specimen during observation. 15mm(9/16")(dia). x
10mm(3/8")(H), 6.4mm(1/4") split.
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• METALLURGICAL LABORATORY TESTING Metallurgical
  labs stocked with state-of-the-art of equipment
  that allows to help in materials selection,
  characterization, component and process design,
  qualification, failure analysis, and many other
  services.
• Specimen Preparation
• Automatic grinding and polishing equipment
• Abrasive cut-off wheels
• Epoxy and cold mount
• Large section specimen (up to 9 in.)
  metallographic preparation
• Acid and electrolytic polishing/etching
  techniques
• Specialized sectioning capability
• Etching techniques for most common materials
• Removal of rust and scale prior to failure
  analysis
• Microstructural Analysis
• Optical microscopes magnification up to 2000x
  with oil immersion
• Scanning Electron Microscope
• Cambridge Stereoscan 360
• Windowless EDS capability for microstructural
  chemical analysis

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• Image Analysis
• Micro- and macro-digital photographic capability
• Quantitative image analysis for
• Area fraction
• Feature measurement
• Modularity
• Grain size
• Size distribution
• Inclusion rating
• Crack length
• Software-based weld profile measurement
  Conventional digital macrophotograph capability
  
• Materials Testing
• Hardness testing (Rockwell A, B, C)
• Microhardness testing (Vickers, Knoop)
• Magne-gage for ferrite measurement

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• Weldability Testing
• Gleeble 1000 Thermal/Mechanical Simulator
• Universal Varestraint
• Oberlikon-Yanaco Hydrogen Analyzer with
  high-temperature measurement capability
• Heat Treatment
• 3-cubic ft. convection furnace
• 12-cubic ft. convection furnace
• 9-cubic ft. oven
• Nondestructive Evaluation (NDE)
• Ultrasonic immersion testing
• Ultrasonic contact testing
• Eddy current testing
• Meandering Winding Magnetometer (MWM)
• Surface cleanliness monitor (Optical Stimulated
  Electron Emission OSEE)
• Magnetic particle testing
• Penetrant testing
• Baroscope and visual inspection
• Radiography

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Thermography

• STANDARD TESTING SERVICES
• Tensile Bend Fatigue
• Charpy impact Fracture toughness (CTOD, JK)
• Heat treatment services (stress relief,
  normalizing ageing)
• Weld cracking sensitivity tests (WIC, Y-groove,
  CTS, GBOP)
• Diffusible hydrogen measurement (Mercury and gas
  chromatography)
• Gleeble Thermo-mechanical simulator
• Weld simulation CCT curves
• Process simulation
• Thermal/mechanical simulation
• Weldability (Varestraint, Sigamajig)
• Microstructural characterization
• Optical Hardness Feature quantification
• Weld procedure qualification
• Residual stress measurements (blind-whole method)
  
• Digital image analysis SEM with
• EDS capability
• Experimental stress analysis (strain gauging
  services)
• High temperature testing up to 1200C