02300nam a2200241   4500001000700000090001100007100004100018101000800059200021100067311008600278330126700364461008401631606002201715606002601737606002901763606002701792606002201819606002001841700001801861701001901879701002801898995013201926376013  a376013  a20151020u           y0pory50      ba  aeng  aA survey of some metallographic etching reagents for restoration of obliteratedengraved marks on aluminium–silicon alloy surfacesbRecurso eletrónicofNorjaidi Uli, R. Kuppuswamy, Mohd Firdaus Che Amran  a(*). Resumo inserto na publicação. Ficheiro de 1,07 MB em formato PDF (8 p.).  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.  dMay 2011vVol. 208, n. 1-3tForensic Science Internationalx0379-0738pp. 66-73  aQUÍMICA FORENSE  aVEÍCULO AUTOMÓVEL  aMARCAÇÃO DE OBJECTOS  aANÁLISE LABORATORIAL  aCIÊNCIA FORENSE  aESTUDO DE CASOS  aULIbNorjaidi  aKUPPUSWAMYbR.  aAMRANbMohd Firdaus Che  104PJ_04_010000000000000__ARTIGOS_DIGITALIZADOS52022-06-069403794aPJcPJkPJ04.01 - Artigos digitalizadosn2022-06-06o0rAP