Irene Mona Peterson

Damage-Resistant Brittle Coatings

Laminate structures consisting of hard, brittle coatings andsoft, tough substrates are important in a wide variety of engi-neering applications (cutting tools, electronic multilayers, la-minated windscreens), biological structures (teeth and dentalcrowns, shells, bones), and traditional pottery (ceramicglazes). A hard outerlayer variously offers increased load-bearing capacity, wear resistance, thermal and corrosion pro-tection, electrical insulation, and aesthetics; a compliant un-derlayer offers stress redistribution and damage tolerance.But hard layers are susceptible to cracking, especially in sur-face-concentrated loads from static or cyclic contacts. In nat-ural or restorative tooth structures, for instance, forces in ex-cess of 100 N operate at contacts between opposing cusps ofcharacteristic radii 2–4 mm over 10

Polishing micro-optic components for use in photonic systems

A fundamental understanding of the mechanisms and variables involved in mechanical and chemical material removal can reduce the trail and error involved in designing a polishing schedule. This paper summarizes some key results from the literature on the relationship between damage mechanisms, removal rates, materials properties and polishing machine variables. A case history on development of a schedule for fiber polishing illustrates some practical examples of the challenges encountered, and also discusses the effects of different abrasive materials.