Micro hardness measurement makes small impression

Citation

(2007), "Micro hardness measurement makes small impression", Anti-Corrosion Methods and Materials, Vol. 54 No. 2. https://doi.org/10.1108/acmm.2007.12854bad.003

Micro hardness measurement makes small impression

Micro hardness measurement makes small impression

The increasingly stringent demands being placed on surface treatment technology has necessitated measuring processes and devices that meet the new requirements. The micro hardness measuring systems Fischerscope HM2000 and Picoindentor HM500 have been researched and developed to offer manufacturing industry and other organisations involved in miniaturisation some of the most flexible and precise hardness measuring systems on the market. In doing so, the systems exceed the requirements of ISO 14577. Two systems, each with their own special attributes, and between them covering virtually all hardness requirements.

The Fischerscope HM2000 measures Martens Hardness, which has the advantage of being free of subjective influences such as the optical measurement of the indentation diagonal.

A clear advantage, but Fischer recognise that needs vary and consequently the flexibility of the HM2000 allows for hardness measurement using Berkovich or a spherical indenter of diameter 0.4mm.

A simple measurement according to Vickers is also possible by the direct measurement of the indentation on the video screen. Probably one of the most significant developments has been the capacity of the HM2000 to handle indentation loads of up to 2N. This is twice the previous maximum test load, which gives it first class precision and reliability and clear-cut measurement results on coatings with rough surfaces and coarse material textures.

New applications cover quality control of hard material coatings on cutting and forming tools, galvanic coatings such as deposited nickel coatings, gold coatings on contacts for electrical components, paint and lacquer in the automotive industry and synthetic foils.

The Picoindenter HM500 has been developed specifically to measure the thinnest nanometer coatings. Its flexibility extends to material characteristic analysis, such as the elastic indentation modulus, simply by evaluating the unload plot.

This is in accordance with DIN EN ISO 14577.

Applications include hard material coatings, ultra thin DLC coatings, dirt-repellent coatings, PC hard disk/ CD coatings, very thin lacquer coatings, ion-implanted surfaces, nanocoatings for sensors, implants/medical technology, matrix effects in alloys, biological materials and ceramic materials.

Precise measurements

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  The specified test load is built up with high precision.

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  The measurement of the indentation depth is carried out with a resolution in the picometer or nanometer range.

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  The extremely sensitive touchdown of the indenter allows for the exact determination of the zero point.

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  This is significantly below the measurement uncertainty of (<1 per cent, prescribed by the standards.

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  The tip roundness of the indenter is determined using a reference measurement, which is taken into account in the results.

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  The microhardness determination is computer controlled and as such is free of any subjective influences, to include the operator.

Versatile measuring results

In one single measurement, the user obtains information about the hardness of the surface, the hardness pattern within boundary layers near the surface, the elastic and plastic properties and the creep properties of the material.

Additional interesting characteristic qualities of the material can be computed from the recorded measurement plot, such as modulus of indentation and the elastic plastic energy portions.

The measuring head has a support ring to ensure damage free touchdown on the specimen surface.

It contains the indenter, which is diamond pyramid as per Vickers, with 136-degree plane angle to meet industry requirements.

It also contains the test load generating unit and the position measuring unit for determining the indentation depth.

Intelligent software

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  The WIN-HCU software provides all functions for controlling the measuring head and enables the user to simply and quickly adjust all the measuring parameters.

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  Even semi-skilled users can make measurements.

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  In addition to the conversion of the indentation hardness into a Vickers value according to ISO 14577-1, a direct measurement of the hardness penetration according to the classic Vickers method is also possible on measuring systems with the optional positioning device.

The key to precise micro-hardness testing

This lies in a robust mechanical instrument insulated from external vibrations with automated measurement avoiding any subjective influences.

When the applied force is measured in steps as it is applied and also as it is removed, the instrument becomes a system giving vital information about the plastic qualities of the sample.

It has never been easier to meet the stringent demands of the new surface treatment technologies. The Fischerscope HM2000 and Picoindentor make a tiny but very significant impression.