Journal of Materials Processing Technology 155–156 (2004) 1132–1137 The use of infrared thermography for materials characterization Carosena Meola a,∗ , Giovanni M. Carlomagno a , Luca Giorleo b a DETEC–Dipartimento di Energetica, Termofluidodinamica Applicata e Condizionamenti Ambientali, Università di Napoli “Federico II”, P.le Tecchio, 80 80125 Napoli, Italy b DIMP–Dipartimento di Ingegneria dei Materiali e della Produzione, Università di Napoli “Federico II”, P.le Tecchio, 80 80125 Napoli, Italy Abstract The aim of the present experimental study is to highlight the help provided by infrared thermography in the characterization of materials. Infrared thermography is a two-dimensional, non-contact technique of surface temperature mapping which can be usefully exploited for quality assurance of manufacturing processes as well as for non-destructive evaluation of end products. Non-destructive evaluation with infrared thermography can be performed in two basic ways: pulse thermography (PT), or modulated lockin thermography (MT). Both techniques are able to reveal material inhomogeneties, which can arise either during manufacturing processes, or in service. In particular, within the MT technique a phase angle value may be associated to a specific characteristic (density, porosity, hardness, etc.) of the material. Thus, MT can be exploited for characterization of many materials either metallic, or plastics, composites, etc. which are commonly used in different fields: alimentary, architectural, automotive, aeronautical, mains. Results prove the capability of MT to discriminate between materials very similar and this feature can be advantageously exploited to evaluate modifications that occur in material characteristics as consequence of ageing, or exposure to adverse environmental conditions. © 2004 Elsevier B.V. All rights reserved. Keywords: Material characterization; Non-destructive evaluation; Lockin thermography 1. Introduction Nowadays, when the modern technological progress comes out in a lot of ever more sophisticated tools able to do everything quickly, from household appliances to high speed transports, the demand of safety is increasing always more. Of course, safety means high production standards as well as maintenance. The first requirement involves ma- terials characteristics and manufacturing processes while the second one periodic inspection with the most adequate non-destructive technique. The researchers’ efforts are currently underway to create new innovative materials of superior properties to be em- ployed for the fabrication of special parts. Leader is the aeronautical field where the challenge is a combination of low weight with high mechanical strength. Composites and particularly hybrid composites as Glare ® (metal laminae plus glass fibres) have been developed and still the technology is sought for improvements. Now a wide area of aircraft surface is in composites (wings, fuselage). On the other hands, a marked reduction in the vehicle weight ∗ Corresponding author. Tel.: +390-81-768-3389; fax: +390-81-768-3389. E-mail addresses: carmeola@unina.it (C. Meola), carmagno@unina.it (G.M. Carlomagno), lgiorleo@unina.it (L. Giorleo). allows for an increase in payable weight (passengers), which may result in economic profit. The development of lighter-high-strength materials is welcomed also in several other fields such as medicine for orthopaedic prostheses (i.e. hip joints), or dental implants. Perhaps, a reduction in weight is the main objective of also the packaging industry, which is daily involved in handling more and more packages. In this context, material characterization represents a key point for product standards and may be performed with both destructive and non-destructive tests. During the design phase, destructive tests help to acquire information about the material behaviour. However, to assure quality, the fab- rication of new materials should be accompanied with the development of effective techniques of non-destructive eval- uation (NDE) to be used for either acceptance/rejection of parts, or for inspection of parts in service. At the moment there are many non-destructive techniques available, but only a few allow in situ analysis. Thus, the requirements for NDE are continuing to be driven by the need for lower cost methods and instruments with greater reliability, sensitivity, user friendliness and high operational speed as well as applicability to increasingly complex ma- terials and structures. Indeed, there is an increasing demand for non-destructive evaluation not only for characterization of novel materials but also for characterization of antique 0924-0136/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jmatprotec.2004.04.268