The Characterization and Deterioration of Modern Metallic Threads

Abstract

The paper describes the analysis (methods and results) of samples removed from 11 textiles dated between 1912 and 1990. Morphological examination was by optical and scanning electron microscopy (SEM), elemental analysis via energy dispersive X-ray microanalysis (ED X), using a scanning electron microscope integrated with an energy dispersive spectrometer system (SEM-EDS). Wavelength dispersive analysis (WDS) enabled the thickness of coatings to be estimated. Plastic films and lacquers were identified using Fourier transform infrared (FTIR) techniques and combustion tests. With metal threads, two metal coating methods not characterized until now were found: gilding silver thread together with the core material by electroplating, and transforming the surface of copper into brass by cementation followed by gilding. Of the synthetic materials, three plastic materials were identified ('Cellophane', cellulose acetate butyrate and polyester), a poly(vinyl chloride) (PVC) lacquer, and a viscose rayon core thread. Following the model set with traditional metallic threads, the modern metallic threads are divided into two groups: solid metal threads and threads made by combining metal and organic material. Inherent processes of deterioration are highlighted.