Developments in micro-and nano-defects detection using bacterial cells

摘要

This paper describes improvements to the Nondestructive Testing (NDT) technique recently proposed, based on the use of bacterial cell suspensions to identify micro-and nano-surface defects. New bacterial strains were used with magnetic fields to improve bacteria mobility. Different materials and defect morphologies were tested, including nanoindentation defects, micro-powder injection moulding components and micro-laser welding. Nanoindentations with 0.6 mu m depth and 5.3 mu m side length were successfully detected. Bacterial cells allow identifying different topographic attributes of the surfaces, such as roughness. Cracks of about 0.5 mu m wide and 10 mu m depth in a reference test block Type 1 were successfully detected. (C) 2015 Elsevier Ltd. All rights reserved.