000			02328nam a2200265 4500
001			376013
090			_a376013
100			_a20151020u y0pory50 ba
101			_aeng
200			_aA survey of some metallographic etching reagents for restoration of obliteratedengraved marks on aluminium–silicon alloy surfaces _bRecurso eletrónico _fNorjaidi Uli, R. Kuppuswamy, Mohd Firdaus Che Amran
311			_a(*). Resumo inserto na publicação. Ficheiro de 1,07 MB em formato PDF (8 p.).
330			_aA 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.
461			_dMay 2011 _vVol. 208, n. 1-3 _tForensic Science International _x0379-0738 _pp. 66-73
606			_aQUÍMICA FORENSE _9343048
606			_aVEÍCULO AUTOMÓVEL _9241256
606			_aMARCAÇÃO DE OBJECTOS _9343973
606			_aANÁLISE LABORATORIAL _9326721
606			_aCIÊNCIA FORENSE _9321508
606			_aESTUDO DE CASOS _9322367
700			_aULI _bNorjaidi _9350459
701			_aKUPPUSWAMY _bR. _9344647
701			_aAMRAN _bMohd Firdaus Che _9350460