Localized surface elasticity measurements using an atomic force microscope

“…The frequency of the applied signal is on the order of hundreds of kilohertz, which is faster than the z feedback loop is set up to track. Thus, topographic information can be separated from local variations in the sample's elastic properties, and the two types of images can be collected simultaneously [3,27,99].…”

Section: Determination Of Elasticitymentioning

confidence: 99%

“…AFM can also be used for nanoindentation to provide in situ imaging ability without moving the sample, switching tips, relocating the area for scanning, or using an entirely different instrument to image the indentation [35,56,71,102,118]. Force modulation microscopy (FMM) which is an extension of AFM imaging, is used extensively for the characterization of mechanical properties and in applications such as imaging composition changes in a composite material, analyzing polymer homogeneity, and detecting contaminants in manufacturing processes [3,27,99]. Assembly of nanoparticles and linking them to electrical leads, such as random deposition of clusters between electrodes, binding by wet chemistry, and electrostatic trapping, all serve as other important applications of the AFM technique.…”

Section: Introductionmentioning

confidence: 99%

A review of atomic force microscopy imaging systems: application to molecular metrology and biological sciences

2004

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“…Maivald et al (1991) and DeVecchio and Bhushan (1997) used an AFM in "force modulation mode" to measure local surface elasticities. AFM tip is scanned over the modulated sample surface with the feedback loop keeping the average force constant.…”

Section: Scratching Wear and Indentationmentioning

confidence: 99%

Micro/Nanotribology: State of the Art and Its Applications

Bhushan

1998

Tribology Issues and Opportunities in MEMS

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Abstract. Atomic force microscopy/friction force microscopy (AFM/FFM) techniques are increasingly used for tribological studies of engineering surfaces at scales, ranging from atomic and molecular to microscales. These techniques have been used to study surface roughness, adhesion, friction, scratching/wear, indentation, detection of material transfer, and boundary lubrication and for nanofabrication/nanomachining purposes. Measurement of atomic-scale friction of a freshly-cleaved highly-oriented pyrolytic graphite exhibited the same periodicity as that of corresponding topography. However, the peaks in friction am those in corresponding topography were displaced relative to each other. Variations in atomic-scale friction and the observed displacement has been explained by the variations in interatomic forces in the normal and lateral directions. Local variation in microscale friction is found to correspond to the local slope suggesting that a ratchet mechanism is responsible for this variation. Directionality in the friction is observed on both micro-and macro scales which results from the surface preparation and anisotropy in surface roughness. Microscale friction is generally found to be smaller than the macrofriction as there is less ploughing contribution in microscale measurements. Microscale friction is load dependent and friction values increase with an increase in the normal load approaching to the macrofriction at contact stresses higher than the hardness of the softer material. Wear rate for single-crystal silicon is negligible below 20 IlN and is much higher and remains approximately constant at higher loads. Elastic deformation at low loads is responsible for negligible wear. Mechanism of material removal on microscale is studied. At the loads used in the study, material is removed by the ploughing mode in a brittle manner without much plastic deformation. Most of the wear debris is loose. Evolution of the wear has also been studied using AFM. Wear is found to be initiated at nano scratches. AFM has been modified to obtain load-displacement curves and for measurement of nanoindentation hardness and Young's modulus of elasticity, with depth of indentation as low as I nm. Hardness of ceramics on nano scales is found to be higher than that on micro scale.Ceramics exhibit significant plasticity and creep on nanoscale. Scratching and indentation on nanoscales are the powerful ways to screen for adhesion and resistance to deformation of ultrathin films. Detection of material transfer on a nanoscale is possible with AFM. Boundary lubrication studies and measurement of lubricant-film thickness with a lateral resolution on a nanoscale have been conducted using AFM. Self-assembled monolayers and chemically-bonded lubricant fLIms with a mobile fraction are superior in wear resistance.

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Localized surface elasticity measurements using an atomic force microscope

Abstract: of tips like the ones used in this work. They were acquired in a private communication with Brandon Comella at Rochester Institute of Technology, Dept. of Mech. Eng., and apply only to tapping mode tips ͑TESP͒ purchased through Digital Instruments.

Cited by 87 publications

References 8 publications

Force-distance curves by atomic force microscopy

Force-distance curves by atomic force microscopy

A review of atomic force microscopy imaging systems: application to molecular metrology and biological sciences

Micro/Nanotribology: State of the Art and Its Applications

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