Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
31
Combustion Methods - High temperature combustion is used to determine carbon and sulfur
content in a variety of materials, both organic and inorganic. The sample is accurately weighed and
placed in a ceramic crucible or combustion boat, often along with combustion accelerators. The
crucible is placed in a high-temperature furnace which is then flooded with oxygen. The furnace is
heated to 1370 - 1425°C, causing the combustion of the carbon and sulfur in the sample to form CO,
CO
2
, and SO
2
. The gases are separated and analyzed by infrared absorption or thermal conductivity
detectors. A heated catalyst is used to convert the CO to CO
2
prior to detection.
The infrared absorption detector measures the absorption of the infrared wavelengths characteristic to
CO
2
and SO
2
.The amount of infrared absorption at these wavelengths is correlated to a quantitative
content based on standards and the weight of the original specimen.
The thermal conductivity detectors monitor the thermal conductivity of the carrier gas. As the evolved
gases pass the detector, changes in the thermal conductivity correspond to a change in the gas (e.g.
from the inert carrier gas to hydrogen) and the amount of evolved gas present. These changes corre-
spond to the amount of CO
2
and SO
2
generated and indicate the amount of sulfur or carbon in the
original specimen.

IG - Inert gas fusion is a quantitative analytical technique for determining the concentrations of
nitrogen, oxygen, and hydrogen in ferrous and nonferrous materials. The sample is accurately weighed
and placed in a pure graphite crucible in a fusion furnace with an inert gas atmosphere. The crucible is
heated to 2000 - 3000°C, resulting in the sample fusing to a molten state. The hydrogen and nitrogen
gases dissociate from the molten material and are carried away from the fusion chamber as H
2
and
N
2
. The oxygen released from the material bonds with carbon (from the graphite crucible) to form
CO or CO
2
and is carried away.
An inert carrier gas flushes the gases evolved from the sample out of the fusion chamber. The fusion
gases are separated and carried to the detector. The individual concentrations for the evolved gases
are detected by infrared absorption (for CO and CO
2
only) or thermal conductive techniques (N
2
,
H
2
, CO, and CO
2
) as described for Combustion Methods above.
ANALYTICAL INFORMATION
Spark-OES - The intensities of the characteristic wavelengths of emitted photons are measured and
compared to intensities for known standards to provide quantitative results. All metallic elements plus
carbon, sulfur, and phosphorus can be detected, with analysis for most performed simultaneously. The
minimum detection limits are in the parts-per-million range.

XRF - The energy of each x-ray and the number of x-rays for each energy are measured. Elements
from beryllium to uranium can be detected. The minimum detection limits are typically in the
parts-per-million range. Because thecharacteristic x-ray intensity will vary with the thickness of films
on a dissimilar substrate, the thickness of thin films can also be measured by XRF.
QUANTITATIVE CHEMICAL A NALYSIS
Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
32
ICP-OES - The intensities of the characteristic wavelengths are measured and compared to intensi-
ties for known standards to provide quantitative results. All metallic elements can be detected, with
analysis for most performed simultaneously. The minimum detection limits are typically
parts-per-million to parts-per-billion for the dissolved samples. Since specimens for this technique
are solutions, standards suitable for most material types can be easily prepared.
Combustion methods - Quantitative results are obtained for carbon and sulfur contents in metals,
inorganics, and organics. Lower detection limits for carbon range from 0.1 to 10 parts per-million
with upper detection limits of 2.5 - 3.5 %. Lower detection limits for sulfur range from 0.1 to 50 parts
per-million with upper detection limits of 0.2 - 2.5 %.
IG - Quantitative results for most metals and alloys can be obtained in the parts-per-million to
parts-per-billion range for nitrogen, hydrogen, and oxygen.
TYPICAL APPLICATIONS
• Alloy identification for ferrous and non-ferrous materials
• Industrial alloy verification for quality control
• Mineral and Cement composition
• Sulfur, chlorine, lead, etc.,determination in petroleum products
• Additives to polymers
• Trace metals in alloys, water, or solutions
• Contamination of water or solutions
SAMPLE REQUIREMENTS
Spark -OES - The sample must be a conductive metallic solid with a minimum diameter of 5 mm or
larger, depending on the instrument.
XRF - The samples may be solids, liquids or powders. Samples often require little or no preparation

prior to analysis. Qualitative analysis may use samples as small as 1 mm across. Quantitative analysis
may require a larger sample, up to 30 mm in diameter.
ICP-OES - The samples may be solid or in a solution. A few grams of a solid sample are typically
needed for digestion and dilution. For samples in solution, at least several milliliters may be required
for dilution.
Combustion methods - One gram or less of a solid, chips, or powder sample is typically required.
Samples should not be contaminated with sulfur or carbon prior to analysis.
IG - One gram of material is required for nitrogen or oxygen determination. Samples may be solids,
chips, or powders. Hydrogen determination generally requires two grams of a solid sample.
QUANTITATIVE CHEMICAL A NALYSIS
Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
33
ROCKWELL HARDNESS TESTING
DESCRIPTION OF TECHNIQUE
Rockwell hardness testing is a general method for measuring the bulk hardness of metallic and poly-
mer materials. Although hardness testing does not give a direct measurement of any performance
properties, hardness of a material correlates directly with its strength, wear resistance, and other
properties. Hardness testing is widely used for material
evaluation because of its simplicity and low cost relative
to direct measurement of many properties. Specifically,
conversion charts from Rockwell hardness to tensile
strength are available for some structural alloys, including
steel and aluminum.
Rockwell hardness testing is an indentation testing
method. The indenter is either a conical diamond (brale)
or a hard steel ball. Different indenter ball diameters from
1/16 to 1/2 in. are used depending on the test scale.
To start the test, the indenter is “set” into the sample at a
prescribed minor load. A major load is then applied and
held for a set time period. The force on the indenter is

then decreased back to the minor load. The Rockwell
hardness number is calculated from the depth of perma-
nent deformation of the indenter into the sample, i.e. the
difference in indenter position before and after application
of the major load. The minor and major loads can be
applied using dead weights or springs. The indenter
position is measured using an analog dial indicator or an
electronic device with digital readout.
The various indenter types combined with a range of test
loads form a matrix of Rockwell hardness scales that are
applicable to a wide variety of materials. Each Rockwell
hardness scale is identified by a letter designation indica-
tive of the indenter type and the major and minor loads
used for the test. The Rockwell hardness number is
expressed as a combination of the measured numerical
hardness value and the scale letter preceded by the
letters, HR. For example, a hardness value of 80 on the
Rockwell A scale is reported as 80 HRA.
FOSNOITACILPPALACIPYT
SELACSTSETLLEWKCOR
ELACSSNOITACILPPA
A,sleetsniht,sedibracdetnemeC
ylnO.sleetsdenedrah-esacwollahs
ediwarevosuounitnocsitahtelacs
.sessendrahlairetamfoegnar
Bdna,sleetstfos,reppoc,munimulA
.norielbaellam
Cpeed,snoridrah,sleetsdenedraH
.muinatit,sleetsdenedrah-esac
Ddenedrah-esacmuidem,sleetsnihT

.norielbaellamcitilraepdna,sleets
E,muisengam,munimula,noritsaC
.slatemgniraebdna
Ftfos,nihtdnasreppocdelaennA
.latemteehs
G,reppocmuillyreb,eznorbrohpsohP
.snorielbaellamdna
H
daeldna,cniz,munimulA
,M,L,K
V,S,R,P
tfosyrevrehtodnaslatemgniraeB
.slairetamnihtro
N,CRH,ARHrofsaslairetamemaS
roeguagrennihttub,DRHdna
.shtpedesac
T,FRH,BRHrofsaslairetamemaS
.eguagrennihtroftub,GRHdna
Y,X,Wyarpsamsalp,slairetamgniraeB
.sgnitaoc
Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
34
ANALYTICAL INFORMATION
Regular Rockwell Hardness Testing - Measures the bulk hardness of the material. There are
separate scales for ferrous metals, nonferrous metals, and plastics. Common Rockwell hardness
scales include A, B,C and F for metals and M and R for polymers.
Superficial Rockwell Hardness Testing - A more surface-sensitive measurement of hardness than
regular Rockwell scales. This technique is useful for testing thin samples, samples with hardness
gradients at the surface, and small areas. Superficial Rockwell hardness scales are N and T for metals
and W, X and Y for nonmetallic materials and soft coatings.

TYPICAL APPLICATIONS
• Quality control for metal heat treatment
• Incoming material inspection
• Weld evaluations in steels and other alloys
• Grade verification for hard plastics
• Failure analysis
SAMPLE REQUIREMENTS
Testing is typically performed on flat or cylindrical samples.
Cutting and/or machining are often required to obtain suitable
test specimens from complex-shaped components. Smooth
parallel surfaces, free of coatings, scale and gross contamina-
tion, are required for
testing. The specific
finish requirements
depend on the material
and test scale.
Samples 6 in. (150
mm) thick or larger can
be accommodated. The
minimum sample size
depends on the sample
hardness and test scale.
Cylindrical samples as
small as 1/8 in. (3 mm)
in diameter, and thin
sheets 0.006 in. (150
µm) thick, are the
minimum size for testing.
ROCKWELL HARDNESS TESTING
Rockwell Hardness Tester

selacStseTssendraHllewkcoR
lobmySelacSrotartenePgkdaoL
AelarB06
BllaB.ni-61/1001
CelarB051
DelarB001
EllaB.ni-8/1001
FllaB.ni-61/106
GllaB.ni-61/1051
HllaB.ni-8/106
KllaB.ni-8/1051
LllaB.ni-4/106
MllaB.ni-4/1001
PllaB.ni-4/1051
RllaB.ni-2/106
SllaB.ni-2/1001
VllaB.ni-2/1051
selacSretseTlaicifrepuS
N54,N03,N51elarBN54,03,51
T54,T03,T51llaB.ni-61/154,03,51
W54,W03,W51llaB.ni-8/154,03,51
X54,X03,X51llaB.ni-4/154,03,51
Y54,Y03,Y51llaB.ni-2/154,03,51
Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
35
SCANNING ELECTRON MICROSCOPY
DESCRIPTION OF TECHNIQUE
Scanning electron microscopy (SEM) is a method for high-resolution imaging of surfaces. The SEM
uses electrons for imaging, much as a light microscope uses visible light. The advantages of SEM over
light microscopy include much higher magnification (>100,000X) and greater depth of field up to

100 times that of light microscopy. Qualitative and
quantitative chemical analysis information is also
obtained using an energy dispersive x-ray spectrom-
eter (EDS) with the SEM. (See Handbook section
on EDS analysis.)
The SEM generates a beam of incident electrons in
an electron column above the sample chamber. The
electrons are produced by a thermal emission
source, such as a heated tungsten filament, or by a
field emission cathode. The energy of the incident
electrons can be as low as 100 eV or as high as 30
keV depending on the evaluation objectives. The
electrons are focused into a small beam by a series
of electromagnetic lenses in the SEM column.
Scanning coils near the end of the column direct and position the focused beam onto the sample
surface. The electron beam is scanned in a raster pattern over the surface for imaging. The beam can
also be focused at a single point or scanned along a line for x-ray analysis. The beam can be focused
to a final probe diameter as small as about 10 Å.
The incident electrons cause electrons to be emitted from the sample due to elastic and inelastic
scattering events within the sample’s surface and near-surface material. High-energy electrons that are
ejected by an elastic collision of an incident electron,
typically with a sample atom’s nucleus, are referred to as
backscattered electrons. The energy of backscattered
electrons will be comparable to that of the incident elec-
trons. Emitted lower-energy electrons resulting from inelas-
tic scattering are called secondary electrons. Secondary
electrons can be formed by collisions with the nucleus
where substantial energy loss occurs or by the ejection of
loosely bound electrons from the sample atoms. The energy
of secondary electrons is typically 50 eV or less.

To create an SEM image, the incident electron beam is
scanned in a raster pattern across the sample's surface. The
SEM Image of Metal Foam Structure
Electron Beam Interaction Diagram
Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
36
emitted electrons are detected for each position in the scanned area by an electron detector. The
intensity of the emitted electron signal is displayed as brightness on a cathode ray tube (CRT). By
sychromizing the CRT scan to that of the scan of the incident electron beam, the CRT display
represents the morphology of the sample surface area scanned by the beam. Magnification of the
CRT image is the ratio of the image display size to the sample area scanned by the electron beam.
Two electron detector types are predominantly used
for SEM imaging. Scintillator type detectors
(Everhart-Thornley) are used for secondary electron
imaging. This detector is charged with a positive
voltage to attract electrons to the detector for im-
proved signal to noise ratio. Detectors for
backscattered electrons can be scintillator types or a
solid-state detector.
The SEM column and sample chamber are at a
moderate vacuum to allow the electrons to travel
freely from the electron beam source to the sample
and then to the detectors. High-resolution imaging is
done with the chamber at higher vacuum, typically
from 10
-5
to 10
-7
Torr. Imaging of nonconductive,
volatile, and vacuum-sensitive samples can be performed at higher pressures.

ANALYTICAL INFORMATION
Secondary Electron Imaging - This mode provides high-resolution imaging of fine surface mor-
phology. Inelastic electron scattering caused by the interaction between the sample's electrons and the
incident electrons results in the emission of low-energy electrons from near the sample's surface. The
topography of surface features influences the number of electrons that reach the secondary electron
detector from any point on the scanned surface. This
local variation in electron intensity creates the image
contrast that reveals the surface morphology. The
secondary electron image resolution for an ideal
sample is about 3.5 nm for a tungsten-filament elec-
tron source SEM or 1.5 nm for field emission SEM.
Backscatter Electron Imaging - This mode pro-
vides image contrast as a function of elemental
composition, as well as, surface topography. Back-
scattered electrons are produced by the elastic
interactions between the sample and the incident
electron beam. These high-energy electrons can
SCANNING ELECTRON MICROSCOPY
Corrosion Product on Inside of Copper Tubing
Laser Welded Wire
Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
37
escape from much deeper than secondary electrons, so surface topography is not as accurately
resolved as for secondary electron imaging. The production effeciency for backscattered electrons is
proportional to the sample material's mean atomic number, which results in image contrast as a
function of composition, i.e., higher atomic number material appears brighter than low atomic number
material in a backscattered electron image. The optimum resolution for backscattered electron
imaging is about 5.5 nm.
Variable Pressure SEM - Traditionally, SEM has re-
quired an electrically-conductive sample or continuous

conductive surface film to allow incident electrons to be
conducted away from the sample surface to ground. If
electrons accumulate on a nonconductive surface, the
charge buildup causes a divergence of the electron beam
and degrades the SEM image. In variable-pressure SEM,
some air is allowed into the sample chamber, and the
interaction between the electron beam and the air mol-
ecules creates a cloud of positive ions around the electron
beam. These ions will neutralize the negative charge from
electrons collecting on the surface of a nonconductive
material. SEM imaging can be performed on a nonconductive sample when the chamber pressure is
maintained at a level where most of the electrons reach the sample surface, but there are enough gas
molecules to ionize and neutralize charging. Variable pressure SEM is also valuable for examination of
samples that are not compatible with high vacuum.
Quantitation - Image magnification is calibrated against a reference standard. Lateral feature dimen-
sions can be readily quantified to an accuracy of less than 0.1 µm. Computer analysis of images can
quantify area or volume fractions and particle shapes and sizes.
Data Formats - Images can be recorded on
Polaroid instant film, low-cost video prints,
videotape, or as bitmap (.bmp), tagged-
image (.tif), or other computer file formats.
TYPICAL APPLICATIONS
• Microscopic feature measurement
• Fracture characterization
• Microstructure studies
• Thin coating evaluations
• Surface contamination examination
• IC failure analysis
SCANNING ELECTRON MICROSCOPY
Cleavage Fracture in Steel

Intergranular Fracture in Steel
Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
38
SAMPLE REQUIREMENTS
In a large-chamber SEM, samples up to 8 in. (200
mm) in diameter can be readily accommodated. Larger
samples, up to 12 in. (300 mm) across can be loaded
with limited stage movement. Sample height is typically
limited to ~2 in. (50 mm). Backscattered electron
imaging can be performed on conductive or noncon-
ductive samples. For secondary electron imaging,
samples must be electrically conductive. Nonconduc-
tive materials can be evaporatively coated with a thin
film of carbon, gold or other conductive material to
obtain conductivity without significantly affecting
observed surface morphology.
Samples must be compatible with at least a moderate vacuum. For high-resolution secondary electron
imaging, the sample environment is at a pressure of 1 x 10
-5
Torr or less. The pressure can be ad-
justed up to about 2 Torr for vacuum sensitive samples.
SCANNING ELECTRON MICROSCOPY
Fatigue Fracture in Aluminum
Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
39
SECONDARY ION MASS SPECTROMETRY
DESCRIPTION OF TECHNIQUE
Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is an analytical technique used to
obtain elemental and molecular chemical data about surfaces (static SIMS), and detect parts per
billion (ppb) concentrations of impurities in semiconductors and metals (dynamic SIMS). All ele-

ments, including hydrogen, are detectable by SIMS.
In ToF-SIMS analysis, the sample is placed in an ultrahigh vacuum environment where primary ions
bombard the sample and sputter atoms, molecules, and molecular fragments from the sample surface.
The mass of the ejected particles (i.e., second-
ary ions) are analyzed via time-of-flight mass
spectrometry.
In the ToF analyzer, ejected ions are accelerated
into the analyzer with a common energy, but at
different velocities depending on the particle
mass. Due to the differences in these velocities,
smaller ions move through the analyzer faster
than the larger ions. The mass of the secondary
ions are determined by their travel time through
the analyzer. SIMS is a surface-sensitive analysis
method, since only the secondary ions generated
in the outermost 10 to 20 Å region of a sample
surface can overcome the surface binding energy
and escape the sample surface for detection and
analysis.
ANALYTICAL INFORMATION
Mass Spectrum - SIMS analysis identifies the elemental and ion composition of the uppermost 10
to 20 Å of the analyzed surface from positive and negative mass spectra. The high resolution of the
ToF analyzer can distinguish species whose masses differ by only a few millimass units.
Depth Profile - During SIMS analysis, the sample surface is slowly sputtered away. Continuous
analysis obtains composition information as a function of depth. Depth resolution of a few angstroms
is possible. High-sensitivity mass spectra can be recorded or reconstructed at any depth of the
profile.
ToF-SIMS Positive Secondary Ion Map
Handbook of Analytical Methods for Materials Copyright © 2001 by Materials Evaluation and Engineering, Inc.
40

Secondary Ion Mapping - A SIMS map measures the lateral distribution of elements and mol-
ecules on the sample’s surface. To obtain a SIMS map, a highly focused primary ion beam is scanned
in a raster pattern across the sample surface, and the secondary ions are analyzed at specific points
on a grid pattern over the selected surface area. Image brightness at each point is a function of the
relative concentration of the mapped element or molecule. Lateral resolution is less than 0.1 µm for
elements and about 0.5 µm for large molecules.
TYPICAL APPLICATIONS
• Identifying lubricants on magnetic hard discs
• Measuring dopant distributions in semiconductors
• Profiling thickness of insulating films on glass
• Mapping elemental and molecular patterned surfaces
• Identifying compounds in thin organic films
• Determining the extent of crosslinking in polymers
SAMPLE REQUIREMENTS
Sample size cannot exceed 3.5 in. (85 mm) in any lateral direction. Height should not exceed 0.8 in
(20 mm). Sample must be compatible with ultra-high vacuum (>1x10
-9
Torr).
SECONDARY ION MASS SPECTROMETRY