Chapter 7
Nano-Mechanical Properties of Solid
Surfaces Obtained by Nano-Indentation
Abstract Nano-indentation is a powerful method for investigating mechanical properties such as hardness, elastic modulus, and yielding strength in a nanometer’s range
(i.e. nano-mechanical properties) of solid surfaces. The nano-mechanical properties
can be determined from the load-depth curves measured by nano-indentation. The
principle, instrumentation, and features of nano-indentation are described as fundamentals. The nano-mechanical properties of bare metal surface, metal oxide surface,
and thin oxide film on metal are explained as typical examples, and the issues for
determination of hardness from the measured load-depth curve in addition to the
indentation size effect on hardness are discussed. Electrochemical nano-indentation
can be achieved during a potentiostatic polarization of a solid electrode in electrolyte solution. The hardness values of passive single crystal iron surfaces obtained
by electrochemical nano-indentation are increased by chromate treatment of the iron
surfaces, which is explained in terms of the promotion of corrosion resistivity due to
chromate treatment.
Keywords Nano-mechanical properties · Nano-indentation · Load-depth curve ·
Hardness · Elastic modulus
7.1 Introduction
Nano-indentation is a powerful method for investigating the mechanical properties
such as hardness, elastic modulus, and yielding strength in a nanometer’s range (i.e.
nano-mechanical properties) of solid surfaces. The nano-mechanical properties of
the sample surfaces without preexisting defects can be evaluated from the load-depth
curves measured by nano-indentation under a maximum load of 10
–5 –10
–4 N because
of a small indentation volume (10
–6 –10
–3
µm
3 ). It is known that the hardness value
obtained by nano-indentation differs from that by micro-indentation even if the same
sample surface is tested. The hardness values obtained by nano- or micro-indentation
depend on the indentation depth, which is named “indentation size effect (ISE)”.
Although the nano-indentation test has been mostly performed for solid surfaces
in air or in vacuum, its test can be applied to a solid electrode in electrolyte solution
by using a miniature electrochemical cell. The latter is named “electrochemical
© Springer Nature Singapore Pte Ltd. 2020
M. Seo, Electro-Chemo-Mechanical Properties of Solid Electrode Surfaces,
https://doi.org/10.1007/978-981-15-7277-7_7
179
Nano-Mechanical Properties of Solid
Surfaces Obtained by Nano-Indentation
Abstract Nano-indentation is a powerful method for investigating mechanical properties such as hardness, elastic modulus, and yielding strength in a nanometer’s range
(i.e. nano-mechanical properties) of solid surfaces. The nano-mechanical properties
can be determined from the load-depth curves measured by nano-indentation. The
principle, instrumentation, and features of nano-indentation are described as fundamentals. The nano-mechanical properties of bare metal surface, metal oxide surface,
and thin oxide film on metal are explained as typical examples, and the issues for
determination of hardness from the measured load-depth curve in addition to the
indentation size effect on hardness are discussed. Electrochemical nano-indentation
can be achieved during a potentiostatic polarization of a solid electrode in electrolyte solution. The hardness values of passive single crystal iron surfaces obtained
by electrochemical nano-indentation are increased by chromate treatment of the iron
surfaces, which is explained in terms of the promotion of corrosion resistivity due to
chromate treatment.
Keywords Nano-mechanical properties · Nano-indentation · Load-depth curve ·
Hardness · Elastic modulus
7.1 Introduction
Nano-indentation is a powerful method for investigating the mechanical properties
such as hardness, elastic modulus, and yielding strength in a nanometer’s range (i.e.
nano-mechanical properties) of solid surfaces. The nano-mechanical properties of
the sample surfaces without preexisting defects can be evaluated from the load-depth
curves measured by nano-indentation under a maximum load of 10
–5 –10
–4 N because
of a small indentation volume (10
–6 –10
–3
µm
3 ). It is known that the hardness value
obtained by nano-indentation differs from that by micro-indentation even if the same
sample surface is tested. The hardness values obtained by nano- or micro-indentation
depend on the indentation depth, which is named “indentation size effect (ISE)”.
Although the nano-indentation test has been mostly performed for solid surfaces
in air or in vacuum, its test can be applied to a solid electrode in electrolyte solution
by using a miniature electrochemical cell. The latter is named “electrochemical
© Springer Nature Singapore Pte Ltd. 2020
M. Seo, Electro-Chemo-Mechanical Properties of Solid Electrode Surfaces,
https://doi.org/10.1007/978-981-15-7277-7_7
179