01731nam a2200169   4500001000700000100004100007101000800048200012900056311008100185330109400266461008401360606002201444606002901466606002601495606002001521700002001541376011  a20151020u           y0pory50      ba  aeng  aRestoration of obliterated engraved marks on steel surfaces by chemical etching reagentbRecurso eletrónicofQingfang Song  aResumo inserto na publicação. Ficheiro de 1,22 MB em formato PDF (4 p.).  aChemical etching technique is widely used for restoration of obliterated engraved marks on steel surface in the field of public security. The consumed thickness of steel surface during restoration process is considered as a major criterion for evaluating the efficiency of the chemical etching reagent. The thinner the consumed thickness, the higher the restoration efficiency. According to chemical principles, maintaining the continuous oxidative capabilities of etching reagents and increasing the kinetic rate difference of the reaction between the engraved and non-engraved area with the chemical etching reagent can effectively reduce the consumed steel thickness. The study employed steel surface from the engine case of motorcycle and the car frame of automobile. The chemical etching reagents are composed of nitric acid as the oxidizer, hydrofluoric acid as the coordination agent and mixed with glacial acetic acid or acetone as the solvents. Based on the performance evaluation of three different etching reagents, the one composed of HNO3, HF and acetone gave the best result.  dMay 2015vVol. 250, n. 1-2tForensic Science Internationalx0379-0738pp. 33-36  aQUÍMICA FORENSE  aMARCAÇÃO DE OBJECTOS  aVEÍCULO AUTOMÓVEL  aESTUDO DE CASOS  aSONGbQingfang