02328nam a2200265 4500 376013 376013 20151020u y0pory50 ba eng A survey of some metallographic etching reagents for restoration of obliteratedengraved marks on aluminium–silicon alloy surfaces Recurso eletrónico Norjaidi Uli, R. Kuppuswamy, Mohd Firdaus Che Amran (*). Resumo inserto na publicação. Ficheiro de 1,07 MB em formato PDF (8 p.). A brief survey to assess the sensitivity and efficacy of some common etching reagents for revealing obliterated engraved marks on Al–Si alloy surfaces is presented. Experimental observations have recommended use of alternate swabbing of 10% NaOH and 10% HNO3 on the obliterated surfaces for obtaining the desired results. The NaOH etchant responsible for bringing back the original marks resulted in the deposition of some dark coating that has masked the recovered marks. The coating had been well removed by dissolving it in HNO3 containing 10–20% acid. However, the above etching procedure was not effective on aluminium (99% purity) and Al–Zn–Mg–Cu alloy surfaces. Also the two reagents (i) immersion in 10% aq. phosphoric acid and (ii) alternate swabbing of 60% HCl and 40% NaOH suggested earlier for high strength Al–Zn Mg–Cu alloys [23] were quite ineffective on Al–Si alloys. Thus different aluminium alloys needed different etching treatments for successfully restoring the obliterated marks. Al–Si alloys used in casting find wide applications especially in the manufacture of engine blocks of motor vehicles. Hence, the results presented in this paper are of much relevance in serial number restoration problems involving this alloy. May 2011 Vol. 208, n. 1-3 Forensic Science International 0379-0738 p. 66-73 QUÍMICA FORENSE VEÍCULO AUTOMÓVEL MARCAÇÃO DE OBJECTOS ANÁLISE LABORATORIAL CIÊNCIA FORENSE ESTUDO DE CASOS ULI Norjaidi KUPPUSWAMY R. AMRAN Mohd Firdaus Che 0 PJ_04_010000000000000__ARTIGOS_DIGITALIZADOS 2022-06-06 403794 PJ PJ PJ04.01 - Artigos digitalizados 2022-06-06 0 AP