Volume 107, Number 6, November–December 2002Journal of Research of the National Institute of Standards and Technology[J. Res. Natl. Inst. Stand. Technol. 107, 639–662 (2002)]Implications of Polishing Techniques inQuantitative X-Ray MicroanalysisVolume 107 Number 6 November–December 2002Guy Re´mondAustralian Key Centre forMicroscopy and Microanalysis,The University of Sydney,NSW 2006, AustraliaandLaboratoire de Microanalysedes Surfaces,Ecole Nationale de Me´caniqueet des Microtechniques,Besanc¸on, FranceClive NockoldsElectron Microscope Unit,The University of Sydney,NSW 2006, AustraliaMatthew PhillipsMicrostructural Analysis Unit,University Technology of Sydney,NSW 2007, AustraliaandClaude Roques-CarmesLaboratoire de Microanalysedes Surfaces,Ecole Nationale de Me´caniqueet des Microtechniques,Besanc¸on, [email protected]@[email protected]@ens2m.frSpecimen preparation using abrasivesresults in surface and subsurfacemechanical (stresses, strains), geomet rical(roughness), chemical (contaminants,reaction products) and physical modifi-cations (structure, texture, latticedefects). The mechanisms involved inpolishing with abrasives are presented toillustrate the effects of surface topography,surface and subsurface composition andinduced lattice defects on the accuracyof quantitative x-ray microanalysis ofmineral materials with the electron probemicroanalyzer (EPMA).Key words: abrasive wear; boundabrasives; chemical-mechanicalpolishing; loose abrasives; polishing;surface and subsurface damage;x-ray microanalysis.Accepted: August 22, 2002Available online: http://www.nist.gov/jresContents1. Introduction ............................ 6402. Abrasive Wear .......................... 6412.1 Two Body Abrasive Wear ............. 6412.2 Three Body Abrasive Wear ............ 6443. Polishing Procedures and Techniques ....... 6453.1 First Stage: Polishing WithCoarse Abrasions .................... 6453.2 Second Stage: Intermediate Polishing . . . 645639Volume 107, Number 6, November–December 2002Journal of Research of the National Institute of Standards and Technology3.3 Third Stage: Final Polishing ........... 6454. Characterization of Polished Surfaces ....... 6464.1 Surface Topography .................. 6464.2 Surface Versus Volume Composition .... 6494.2.1 Massive Specimens ............ 6494.2.2 Inclusions ..................... 6504.3 Structural Disorders and SubsurfaceLattice Defects ...................... 6515. Implications of the Polishing Procedure inQuantitative X-Ray Microanalysis .......... 6535.1 Layered Structures Resulting FromPolishing ........................... 6535.2 Electrostatic Charging Phenomena ...... 6546. Discussion ............................. 6577. Conclusion............................. 6608. References ............................. 6611. IntroductionAn optically flat polished surface is a necessarycriterion satisfying the geometrical conditions forquantitative x-ray microanalysis with the electron probemicroanalyzer (EPMA). All mechanical, structural,physical and chemical surface modifications resultingfrom the surface preparation will affect the accuracy ofquantitative x-ray microanalysis as previously reportedby Re´mond [1]. The objective of this presentation is toconvey to the EPMA community that polishing withabrasive particles is a complex operation involvingmany experimental and instrumental factors that arecharacteristic of the materials to be polished. For thispurpose, the mechanisms involved in abrasive wear willbe presented in order to illustrate some consequences ofthe polishing procedure on the reliability of quantitativex-ray microanalyses.Mechanical polishing is performed by means ofabrasives with decreasing grain size until scratches areno longer visible (optically polished surface). From amechanical point of view, during the first stage ofpreparation, coarse grains are used to remove initialsurface topographical and chemical defects. The nextstage with smaller abrasive grain size aims to obtain thefinal quality of the surface satisfying the conditions forEPMA analysis. This regime is often divided into twooperations, e.g., the intermediate polishing and the finalpolishing.The mechanisms involved in mechanical polishingusing abrasive particles are part of tribology, thediscipline studying mater ial science, physics, chemistryand surface contact engineering [2-5]. A description ofa tribological system (according the norm DIN 50 320)consists of a set of experimental parameters (appliedload, velocity and duration of the motion) and the systemstructure (the two bodies in contact, the interfacial andsurrounding media), as shown in Fig. 1.Wear is defined as a cumulative surface damagephenomenon in which material is removed from a bodyas small debris particles, primarily by mechanicalprocesses. The wear mechanism is the transfer of energywith removal or displacement of material. The fourmajor wear mechanisms are adhesion, abrasion, surfacefatigue and tribochemical reactions. In polishing withabrasive particles, the wear mechanism is mostlyabrasive wear but other mechanisms are also possible.The abrasive mechanisms occurring in a dry or humidenvironment, result from the simultaneous actions ofnormal and tangential forces and are materialized bythe development of ploughing grooves or scratcheswhich are in some instances accompanied by hertzianfractures. For the classification of the abrasive wearmodes, we will use the most widely accepted terminol-ogy known as two-body abrasion and three-body abra-sion. This terminology illustrates the experimentalsituations encountered in the polishing techniques asillustrated in Fig. 2. In a two-body mode, the boundabrasive particle (identified as a guided-cutting tool) issolidly fixed to the substrate (Fig. 2a). In a three bodyFig. 1. Schematic representation of a tribological system according tothe norm DIN 50 320. The tribological system consists in (1) thespecimen to be polished, (2) the abrasive specimen, (3) the interfacialmedium and (4) the surrounding medium.640Volume 107, Number 6, November–December 2002Journal of Research of the National Institute of Standards and Technologyabrasive mode, free (or loose) particles form a slurrybetween the specimen surface to be polished and a flatpolishing substrate as illustrated in Fig. 2b. The freeparticles in a three-body wear mode may be intention-ally added abrasives or be detached debris from theworn surface.The
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