03073nam a2200265 4500 376009 376009 20151020u y0pory50 ba eng An investigation into the suitability of some etching reagents to restoringobliterated stamped numbers on cast iron engine blocks of cars Recurso eletrónico Mohd Farizon Abdul Wahab, Nurul Izwani Mohamad Ghani, R. Kuppuswamy (*). Resumo inserto na publicação. Ficheiro de 3,17 MB em formato PDF (11 p.). Most of the automotive companies use cast iron for their engine blocks. Restoration of obliterated number on these iron surfaces by chemical etching is known to be quite difficult. Heating of the obliterated surface using oxyacetylene flame is an alternative recovery treatment suggested in literature and used in practice. However chemical etching has been established to be the most sensitive technique for detection of metal deformation present under stamped serial numbers. Hence, the current work investigated the suitability of some common etchants on cast iron surfaces with a view to determining the most suitable one for revealing the obliterated marks. The reagents tested were mostly copper containing Fry’s reagent and its modifications. Two cast iron engine blocks (3.29%C and 3.1%C) of two cars – a Proton Saga and a Toyota – were utilized for the experiments. The engine blocks were cut into several small plates and each plate was stamped with some numerical characters at 8 kN load using Instron Table Mounted Universal Testing Machine. The depth of stamping impression varied between 0.2 mm and 0.3 mm. The stamped number was completely ground off manually using a metal file. The grounded surface was then polished smooth using emery papers and etched with a few selected reagents mostly by swabbing. Experimental results showed that a modified Fry’s composition consisting of 45 g CuCl2, 100 mL HCl, and 180 mL H2O restored the number with better contrast at a reasonably shorter time. The above reagent is a slightly modified form of one of the Fry’s original compositions – 45 g CuCl2, 180 mL HCl, and 100 mL H2O. Quite importantly the proposed reagent restored the original stamped numbers of both Proton and Toyota cars and also a Mitsubishi car that hadbeen obliterated. The most widely used Fry’s composition (90 g CuCl2, 120 mL HCl and 100 mL H2O), although recovered the obliterated number, did not cause the desired contrast. November 2012 Vol. 223, n. 1-3 Forensic Science International 0379-0738 p. 53-63 VEÍCULO AUTOMÓVEL MARCAÇÃO DE OBJECTOS ANÁLISE LABORATORIAL ESTUDO DE CASOS QUÍMICA FORENSE WAHAB Mohd Farizon Abdul GHANI Nurul Izwani KUPPUSWAMY R. 0 PJ_04_010000000000000__ARTIGOS_DIGITALIZADOS 2022-06-06 403790 PJ PJ PJ04.01 - Artigos digitalizados 2022-06-06 0 AP