Micro-surface and bulk thermal behavior of a single-grain decagonal Al-Ni-Co quasicrystal

Scanning thermal microscopy is used to examine the thermal behavior of specific surfaces of a similar to0.8 cm(3) single-grain Al74Ni10Co16 decagonal quasicrystal. The response of a micro-thermal probe in contact with aperiodic and periodic surfaces in air reveals the anisotropic heat flow of the decagonal structure. Heat dissipation with the probe on the aperiodic surface is higher than when the probe is on the periodic surface. While the SThM technique is generally considered to be constrained to the surface region below the nominally 2-5 mum probe tip radius, the heat flow data obtained are clearly comprised of contributions from both the lateral surface around the probe tip and a volume normal to the surface in contact. Heat flow in the decagonal Al74Ni10Co16 quasicrystal can be modeled by an elliptical distribution of thermal diffusion. Parameters for the model used in this study were obtained by making bulk thermal diflusivity measurements using the laser flash method on specimens along the 2- and 10-fold directions. The model was applied to a surface oriented 45degrees to the major axes and verified from bulk measurements obtained from a sample cut along this orientation. (C) 2004 Elsevier B.V. All rights reserved.