Surface characterization

SURFACES & COATINGS / TREATMENTS

TEC Star is able to provide to all its customers a complete service of characterization, designed to solve the typical problems concerning surfaces and innovative coatings and surface treatments.
Using instruments and tools that represent the state of the art about surfaces scientific research, TEC Star can approach industrial problem solving, making accessible to its customers all the technical resources and expertise necessary to have a deep understanding about surfaces.

Below is reported a list of topics and materials that can be analyzed, together with some interesting and representative case history:

 

SURFACE CHEMICAL ANALYSIS

The surface of materials is a major issue because it determines the behaviour of a structure along its whole life, being the connection with the external environment. The surface is the first part of an object to degrade, even just being in contact with the outside atmosphere (oxidation, corrosion, colour modification, chemical contaminations, etc.). The coatings or the surface treatments could be the obvious solution to protect the surface, but sometimes it is not easy to understand why a coating or a treatment shows undesirable defects.

The analytical techniques that TEC Star provides to its customers, allow to have a complete chemical investigation of the surface, revealing the presence of chemical elements and coatings even at thickness of few millionths of a millimeter (few nanometers), with the chance to understand and characterize the chemical bonds of the various elements that compose them (for example the oxidation states, the valence, etc..).

In this way is possible to investigate, for example: surface contaminations (verifying cleanliness and sterilization of surfaces); changes in physical and chemical characteristics (degradation due to chemical reactions or exposure to sun); failure analysis of thin coatings or treatments (plasma treatment, PVD, PECVD, electrodeposition plating); composition analysis of thin coatings in depth (undesired layers of oxidized material, interface analysis between coating and substrate, depth profiling).

A description of the analytical techniques available and some case histories are downloadable at the following links:

TRIBOLOGICAL TESTS

Tribology is the science that deals with all the processes that occur during contact between materials. The study of the tribological properties of materials allows to determine the friction coefficient, the wear rate or the scratch resistance, etc..; in addition is further possible to test the efficiency of lubricants, changing the working conditions (temperature, materials, chemical additives, etc..).

To measure the tribological properties of a specimen, it is necessary to test it in a “controlled simulation” trial, using an instrument (called tribometer) that is able to mimic the conditions of work. To have a complying test, there are several contact geometries among coupled materials to simulate. The tools that TEC Star provides to its customers include many different configurations (block-on-ring, ball-on-disc, pin-on-disc, fretting) in order to have a test a close as possible to real conditions.
The problems that can be solved with the tribological tests include, for example: checking effectiveness of scratch and wear resistant coatings (electrodeposited and PVD coatings, paints, etc.); checking the behavior of lubricants at low or high temperature; measuring the sliding friction coefficient of hi-tech composite polymers (PTFE, MoS2, graphite).

To better understand potentiality of the tests available and which characteristics can be measured, a description of the technical instrumentation and an example of real application is reported below (case history):

Tribological analysis (friction coefficient, wear, lubrication) >>> see the case history

MICRO AND NANO-HARDNESS

Hardness is a fundamental characteristic of materials in order to define the general behavior of a specimen. Traditionally hardness is defined as the resistance of materials to plastic deformation under the action of an external force applied through an “indenter” made of steel or other harder materials, with a variable geometry (Berkovich, Vickers, Knoop, etc..).

In case of thin films and coatings, reliability of hardness measurement depends on the ratio between the depth of indentation and the thickness of the coating, that cannot exceed 1/10 (otherwise the measurement will be affected by the hardness of the substrate).

In case of “traditional” coatings (electrodeposited coating, electroless Nickel plating, Hard chrome plating, etc.), where the thicknesses are in the tenths of a millimeter range, the process is called micro-hardness (the indenter penetrates for tens of microns).

In case of innovative coatings or treatments (PVD, PECVD, vacuum plasma surface treatment), where the thicknesses are in the thousandths of a millimeter range (few microns), it is necessary to carry out indentations with depth in the hundredths of a micron range (nanometers), that means measuring the nano-hardness.

The topics that can be solved with the hardness tests include, for example: determining the best surface coating for anti-scratch or anti-wear applications, variation of surface hardness for coatings in different humidity or temperature conditions, accurate hardness measurement for non-homogeneous metallic composite (Hardness mapping for cemented carbides), hardness depth profiling for laser cemented materials.

To better understand what is possible to obtain with these tests, a data-sheet about the technical instrumentation and an example of real application (case history) are reported below:

Micro and nano-hardness >>> see the case history

MICRO AND NANO-MORPHOLOGY

Morphology of surfaces is a major topic in order to comprehend the behavior of materials while they are working and to understand any reason for the failures that can eventually occur.

In general, the microscopic morphology of the surfaces is investigated using high resolution scanning electron microscopes with (SEM). TEC Star can provide its customers with these instruments and other more advanced. Such as focused ion beam (FIB dual beam mode), that is a high resolution SEM that can modify the matter, performing in situ cross-sections at a nanometer level.

These instruments are able to investigate materials and surfaces morphology, up to resolutions of few thousandths of a micron, allowing observation of powders (even ultrafine powders), coatings and surface treatments (with thickness down to few nanometers), on different kind of materials (metals, ceramics, polymers, etc.).
To better understand what is possible to obtain with these tests, a data-sheet about the technical instrumentation and an example of real application (case history) are reported below:

Micro and nano-morphology >>> see the case history

CRYSTALLOGRAPHY

 X-Ray Diffractometry (XRD, X-Ray Diffraction) allows to detect the crystal structures of a sample (both single elements, and molecules) with an accurate quantitative determination of the crystalline phases.

It is a non-destructive analysis, that also allows to detect the chemical composition of a material, considering that the only phases that can be detected are the crystalline ones (amorphous phases can be analyzed only by grinding the sample in powder form).

X-Ray Diffraction, available for the customers of TEC Star, can be used to: determine the average size of crystalline inorganic fillers of a composite material; determine the average size of nanoparticles; quantify the residual stress within metal specimens or surface coatings.

To better understand what is possible to obtain with this analysis, a data-sheet about the technical instrumentation and an example of real application (case history) are reported below:

X-Ray crystallography (XRD) >>> see the case history

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