This document provides information about testing methods for ceramics. It discusses several techniques for analyzing the chemical composition, optical properties, and mechanical properties of ceramics. Specifically, it describes X-ray photoelectron spectroscopy for elemental analysis, secondary ion mass spectrometry for surface composition analysis, energy dispersive X-ray spectroscopy for elemental quantification, and various tests for measuring hardness, strength, gloss, refractive index, and color.

1. CERAMIC TESTING
Presented by Menna Koriam

2. Contents
What is ceramics ?
Chemical composition (Microstructure)
Optical properties
Mechanical properties
Surface Properties

3. What is ceramics?
• Its a dental material used by to create restorations, such as crowns , bridges and
veneers.
• The word "ceramic" is derived from the greek word keramos, meaning "potter's
clay".
• It came from the ancient art of fabricating pottery where mostly clay was fired to
form a hard, brittle object; a more modern definition is a material that contains
metallic and non-metallic elements (usually oxygen).
• These materials can be defined by their inherent properties including their hard,
stiff, and brittle nature due to the structure of their inter-atomic bonding, which is
both ionic and covalent.
• Ceramics can vary in opacity from very translucent to very opaque. In general, the
more glassy the microstructure (i.E. Noncrystalline) the more translucent it will
appear, and the more crystalline, the more opaque.

4. Ceramic Testing
Chemical Composition
(Microstructure)
Physical Properties
(Optical)
Mechanical properties
Bulk
Dynamic
Static
Surface
Hardness
Surface Topography

5. Chemicalcomposition: SIMS
EDX
XPS

6. I. X-Ray photoelectron spectroscopy (XPS)
• Is a surface-sensitive quantitative spectroscopic technique that measures
the structure of atoms , the elemental composition at the parts per
thousand range, empirical formula, chemical state and electronic state of
the elements that exist within a material.
• XPS spectra are obtained by irradiating a material with a beam of X-
rays while simultaneously measuring the kinetic energy and number
of electrons that escape from the top 0 to 10 nm of the material being
analyzed.

9. • The photoelectrons’ binding
energy depends on:
1. The atomic orbital from which
they originated.
2. The parent atom.
3. The chemical environment of
the atom.
N.B: The information gained is
qualitative & semi-quantitative.

10. Their components include:
1) Source of X-ray.
2) Ultra-high vacuum(UHV) stainless
steel chamber with UHV pumps.
3) Electron collection lens.
4) Electron energy analyzer.
5) Metal magnetic field shielding.
6) Electron detector system.
7) Moderate vacuum sample
introduction chamber.
8) Sample mounts, a sample stage,
and a set of stage manipulators.

11. Used In Measurement of:
1. Elemental composition of the surface (top 0 –10 nm usually).
2. Empirical formula of pure materials.
3. Chemical or electronic state of each element in the surface.

12. II. Secondary Ion Mass Spectroscopy (SIMS)
• It’s UHV (ultra high vacuum) method based on using a focused beam of ions
(usually Xe+ or Ga+). This technique is used to analyze the composition of
solid surfaces and thin films by sputtering the surface of the specimen with a
focused primary ion beam and collecting and analyzing ejected secondary
ions
• The mass/charge ratios of these secondary ions are measured with a mass
spectrometer to determine the elemental, isotopic, or molecular composition
of the surface to a depth of 1 to 2 nm.
• Energy from the incident ion beam (3-5 KeV) impacts the surface of a
material producing fragmentation of the outer atomic layers into neutral,
anionic and cationic species.
• Flux of bombarding ions result in minimal surface etching and produce data
consistent with the surface chemistry.

13. • Mass Spectrometry is an analytical technique that
sorts ions based on their mass (or "weight").
• The type of information gained from SIMS is qualitative chemical
analysis: isotopes, charged molecular fragments and chemical
structure of compounds.
Application of SIMS:
• Valuable in implant research for determining the molecular
species at the outermost surface with high sensitivity.
• The information depth is equal or less than 1 nm.
• The detection sensitivity ranges from 107 – 1011 atoms/cm2

15. Time-of-flight mass spectrometry (TOFMS)
• is a method of mass spectrometry in which ions are accelerated
by an electric field of known strength.
• The velocity and the time that it subsequently takes for the
particle to reach a detector at a known distance both depend on
the mass-to-charge ratio of the particles (heavier particles reach
lower speeds).

17. SIMS consists of:
(1) Primary ion gun generating the primary ion beam.
(2) Primary ion column, accelerating and focusing the beam onto
the sample.
(3) High vacuum sample chamber holding the sample and the
secondary ion extraction lens.
(4) Mass analyzer separating the ions according to their mass to
charge ratio.
(5) Detector.

19. III. Energy dispersive x-ray analysis
spectrometer (EDS OR EDX)
• It is an analytical technique used for the elemental
analysis or chemical characterization of a sample.
• It relies on an interaction of a source of X-ray excitation and
a sample.
• Its characterization capabilities depends on that each element has a
unique atomic structure allowing a unique set of peaks on its
electromagnetic emission spectrum.

20. • At rest, an atom within the sample contains unexcited electrons
in discrete energy levels
• To stimulate the emission of characteristic X-rays from a
specimen, a high-energy beam of charged particles such
as electrons or protons, or a beam of X-rays, is focused into
the sample being studied.
• The incident beam may excite an electron in an inner shell,
ejecting it from the shell while creating an electron hole where
the electron was primarily placed.

21. • An electron from an outer, higher-energy shell then fills the hole,
and the difference in energy between the higher-energy shell and
the lower energy shell is released in the form of an X-ray.
• The number and energy of the X-rays emitted from a specimen can
be measured by an energy-dispersive spectrometer.
• As the energies of the X-rays are characteristic of the difference in
energy between the two shells and of the atomic structure of the
emitting element, EDS allows the elemental composition of the
specimen to be measured.

23. • Four primary components of the EDS setup are:
1. The excitation source (electron beam or x-ray beam)
2. The X-ray detector (a detector is used to convert x-ray energy
into voltage signals).
3. The pulse processor (which measures the signals and passes
them onto an analyzer).
4. The analyzer (for data display).

25. 1.Qualitative analysis:
• The sample x-ray energy values from the EDS spectrum are
compared with known characteristic x-ray energy values to
determine the presence of an element in the sample. Elements
with atomic number ranging from that of Beryllium to Uranium
can be detected.
2.Quantitative analysis:
• Quantitative results can be obtained from the relative x-ray
counts at the characteristic energy level for the sample
constituents. Semi-quantitaive results are readily available.
Analysis:

26. • Atoms are exposed to a high voltage beam in vacuum and they
emit X-rays.
• Each type of atom emits X-rays of specific voltage.
• An energy dispersive X-ray spectrometer records and displays
the emitted X-ray voltages.
• It’s displayed as an XY plot with the X-ray voltage on the X-axis
and the total X-ray counts on the Y-axis called X-ray spectrum.
• Then a software program collects the data from the plot into
weight percent or mole percent calculations.

28. Optical properties
Spectrophotometer
Gloss meter
Refractometer
Colorimeter

29. Spectrophotometer:
• Spectrophotometry is the quantitative measurement of the
reflection or transmission properties of a material as a function
of wavelength (transparent or opaque solids).
• A spectrophotometer consists of two instruments
a spectrometer for producing light of any selected color and
certain wavelength, and a photometer for measuring the
intensity of light.

30. Principle
• The Spectrometer produces a desired range of wavelength of
light. First a collimator (lens) transmits a straight beam of light
that passes through a monochromator (prism) to split it into
several component wavelengths (spectrum). Then a wavelength
selector (slit) transmits only the desired wavelengths,

32. • The Photometer: After the desired range of wavelength of
light passes through the solution of a sample in cuvette, the
photometer detects the amount of photons that is absorbed and
then sends a signal to a galvanometer or a digital display
• The amount of light passing through the object is measured by
the photometer.
• The photometer delivers a voltage signal to a display device,
normally a galvanometer.
Principle

33. • The instruments are arranged so that the object can be placed
between the spectrometer beam and the photometer.
• To know the concentration of the color; the degree of
absorbance of light is proportional to the concentration of color.
• Concentration can be measured by determining the extent of
absorption of light at the appropriate wavelength. For example
hemoglobin appears red because the hemoglobin absorbs blue
and green light rays much more effectively than red.

34. Gloss Meter
A gloss meter is an instrument which is used to
measure specular reflection gloss of a surface.
• Gloss is determined by projecting a beam of light at
a fixed intensity and angle on the surface to be
measured and a filtered detector located to measure
the amount of reflected light at an equal but opposite
angle.
• Gloss Unit: The ratio of reflected to incident light for
the specimen, compared to the ratio for the gloss
standard, is recorded as gloss units (GU).

35. • The measurement scale is based
on a highly polished reference
black glass standard with a
defined refractive index having a
specular reflectance of 100 GU at
the specified angle.
• This standard is used to establish
an upper point calibration of 100
with the lower end point
established at 0 on a perfectly
matte surface.
• Three measurement angles (20°,
60°, and 85°) are specified to
cover the majority of industrial
coatings applications.

36. The angle is selected based on the anticipated
gloss range, as shown in the following table.

37. • For example, if the measurement made at
60° is greater than 70 GU, the
measurement angle should be changed to
20° to optimize measurement accuracy.
• Two additional angles are used for other
materials:
1) An angle of 45° is specified for the
measurement of ceramics, films, textiles
and anodised aluminium.
2) An angle of 75° is specified for paper
and printed materials.

38. Refractometer
• Laboratory device used for measuring of an index of refraction.
• Automatic refractometers measure the refractive index of a sample.
The automatic measurement of the sample is based on the
determination of the critical angle of total reflection.
• A light source, an LED, is focused onto a prism surface through a
lens system. An interference filter guarantees the specified
wavelength. Due to focusing light to a spot at the prism surface, a
wide range of different angles is covered.

39. • Depending on its refractive index, the incoming light below the
critical angle of total reflection is partly transmitted into the sample,
whereas for higher angles of incidence the light is totally reflected.
• This dependence of the reflected light intensity from the incident
angle is measured with a high-resolution sensor array.
• From the video signal taken with the CCD sensor the refractive
index of the sample can be calculated.
• The reflected light intensity from the incident angle is measured
and together with the image detector sensor CCD the refractive
index is calculated

41. Colorimeter
• Measures the value and filters light into red,
green and blue.
• Complete tooth image is obtained through
three separate database for :gingival ,
middle and incisal third.
Cons:
• Can not detect spectral reflectance, less
accurate than spectrophotometer.
• Aging of filter affects its accuracy.

42. Mechanical
Properties
Bulk
Static
Dynamic
Surface
Hardness

43. Bulk Properties
I. Static(Diametral tensile test)
Method:
• A disk of the brittle material is
compressed diametrically in a testing
machine until fracture occurs.
• The compressive stress applied to the
specimen introduces a tensile stress
in the material in the plane of the force
application

44. Bulk Properties
I. Static (Flexural Strength)
Flexural testing is used to determine the flex or bending properties of
a material. Sometimes referred to as a transverse beam test
Method:
It involves placing a sample between two points or supports and
initiating a load using a third point or with two points which are
respectively call 3-Point Bend and 4-Point Bend testing.
Maximum stress and strain are calculated on the incremental load
applied. Results are shown in a graphical format results including the
flexural strength (for fractured samples) and the yield strength
(samples that did not fracture). Typical materials tested are plastics,
composites, metals, ceramics.

45. Bulk Properties
I. Static (Flexural Strength)

46. Bulk Properties
II. Dynamic (Fatigue test )
Method:
• This test is performed by subjecting the specimen to alternating
stress applications below its yield strength until fracture occurs
• It depends on the magnitude of load and the number of cycles
• Fatigue strength: the stress level at which a material fails under
repeated loading.

47. Bulk Properties
II. Dynamic (Fatigue test )
Fatigue data are often represented by an S-N curve.
• ↑ stress→ ↓ number of cycles.
• ↓ stress→ ↑ number of cycles.
• To specify the fatigue strength, specifying the number of cycles is a must.
The endurance(fatigue) limit the highest stress at which the specimen can
be loaded for an infinite number of cycles without failing.

48. Surface Properties
I. Hardness
• Method:
• Applying a standardized force or weight to an indenter →
producing a symmetrically shaped indentation → measured
under a microscope for depth, area, or width.
• With a standardized indenter→ the indentation dimension varies
inversely with the material resistance to penetration.

49. Knoop Hardness test
• Indenter: pyramid shape diamond.
• Shape of indentation: rhomboid indentation
having a long and short diagonal of ratio 7:1.
• Load does not exceed 3.6 kgs

50. Pros:
• Very light loads → produce delicate micro-indentation.
• Materials with a great range of hardness can be tested simply
by varying the test load.
• Suitable for metals, brittle and elastic materials (universal test)
Cons:
• 1) need a highly polished and flat test specimen.
• 2) longer time is needed.

51. Vickers test:
• Indenter: a square based diamond.
• Shape of indentation: square in shape.
Pros:
• - Suitable for brittle materials and ductile materials.
Cons:
• - Not suitable for materials which exhibit elastic recovery.

52. Nano indentation test
• Many materials have microstructural constituents as in case of
micro-filled composites where filler phases are smaller than the
dimensions of the indenter.
• In this regard, we need smaller indenters and to control the
location to create nano-indentation.
Pros:
• Can measure elastic modulus.
• Can measure yield strength and fracture toughness for brittle
materials.

53. Thank you..