Tribo-Rheometry accessories | Rheometer |Thermo Fisher US

Tribo-rheometry introduction

Tribology is the science of interacting surfaces in relative motion and includes the study of friction, wear, and lubrication. The term is derived from the Greek words "tribos" (to rub) and "logos" (study of). Typical tribological measurements include the determination of a coefficient of friction depending on the relative speed of two surfaces.

Determination of a coefficient of friction depending on the relative speed of two surfaces.

The results of tribological experiments are often displayed in the form of a so-called Stribeck curve where the measured coefficient of friction is plotted as a function of sliding speed (the relative motion of the two investigated surfaces). The interaction (friction) of the two surfaces can be measured directly, or indirectly via the dependence of a friction-changing (lubricating) substance. A simplified version of a Stribeck curve for a test including both components, interacting surfaces, and a lubricating substance is shown in this schematic:

Stribeck curve.

Tribo-rheometry applications

Tribology and rheology (the science of flow and deformation of matter) are closely linked and play an important role in many industries such as automotive, construction, food, and personal care. Using the extended possibilities of a modern rotational rheometer to carry out tribological measurements with suitable measuring geometries in addition to conventional rheological tests can therefore be a great advantage. Thermo Scientific HAAKE MARS Rheometers can be equipped with different tribo-rheometry geometries for various applications.

Tribo-rheometry of food

Tribological tests are used to determine the lubrication properties of food products. This information helps in understanding how the product is perceived by the consumer during mastication and swallowing. This information can support the development of new foods with a desirable mouthfeel.

Tribo-rheometry of lubricants

Tribology is extensively used to assess lubricants and greases, providing critical information on their performance and effectiveness.

This includes the measurement of friction and wear under controlled conditions. The obtained results reveal how well a lubricant reduces friction and wear between moving components.

Tribo-rheometry of personal care / cosmetics

Tribological analysis supports the evaluation and optimization of cosmetic products to ensure that they meet consumer expectations in terms of texture, application, and performance. They provide a better understanding of the friction and wear process on the skin and hair during the application of cosmetic products.

Tribo-rheometry techniques

A comprehensive portfolio of tribo-rheometry measuring geometries is available for the Thermo Scientific HAAKE MARS 40 / 60 and the Thermo Scientific HAAKE MARS iQ Rheometer series.

For temperature-dependent measurements, the tribo-rheometry measuring geometries can be used with any standard temperature control module for parallel plates and cone & plate measuring geometries. An optionally available sample cover or an active upper-temperature control module may also be used. In addition, it is also possible to carry out tribological tests in a closed temperature chamber, which ensures a homogeneous temperature distribution over a wide temperature range.

Tribo-rheometry measuring geometry portfolio

The different tribo-rheometry measuring geometries consist of an upper rotor with quick coupling, automatic recognition (“Connect Assist”), and a flexible spring element that guarantees self-alignment, as well as a lower attachment into which a lubricating substance can be filled. The rotor and the lower attachment are modular so that various combinations of different contact surfaces are possible.

Advantages of the tribo-rheometry configurations with the HAAKE MARS Rheometers:

Switching between different configurations is quick and easy.
Comprehensive selection of different contact parts allows for numerous geometry combinations.
Upper surface contacts (balls) with diameters of ½" or ¼" made of steel, stainless steel, ceramic, or glass are available.
Lower attachment can be equipped with contact surfaces in the shape of balls, plates, or discs made of various materials including crosslinked Polydimethylsiloxane (PDMS) for performing soft-tribological measurements on food or cosmetic samples.
‘’Connect Assist’’ functionality provides quick coupling and automatic recognition of the measuring geometry.
Temperature control options enable tribological tests over a wide temperature range.