Recovering obliterated engraved marks on aluminium surfaces by etching technique
Mohd Izhar Mohd Baharum1, R Kuppuswamy, Azari Abd Rahman
1Forensic Science Programme, School of Health Sciences, Universiti Sains Malaysia, Kampus Kesihatan, 16150 Kubang Kerian, Kelantan, Malaysia.
Forensic Science International
|March 4, 2008
Summary
A novel etching technique effectively restores obliterated engraved marks on aluminum surfaces. A specific hydrochloric acid and sodium hydroxide mixture achieved the best results, restoring marks erased up to 0.04mm deep.
Area of Science:
- Materials Science
- Forensic Science
- Metallurgy
Background:
- Engraved marks are crucial for identification and authentication.
- Obliteration of these marks poses challenges in forensic investigations.
- Restoration techniques are vital for recovering such marks.
Purpose of the Study:
- To investigate the effectiveness of etching techniques for restoring obliterated engraved marks on aluminum surfaces.
- To identify the optimal etching reagent and conditions for mark restoration.
- To determine the relationship between metal thickness and restoration depth.
Main Methods:
- Testing various etching reagents on 0.61mm and 1.5mm thick aluminum sheets with erased engraved marks.
- Utilizing a specific reagent mixture of 60% hydrochloric acid and 40% sodium hydroxide.
- Analyzing the depth of restoration and contrast of the restored marks.
Main Results:
- A mixture of 60% hydrochloric acid and 40% sodium hydroxide proved most effective.
- This reagent restored marks erased up to 0.04mm on 0.61mm thick aluminum.
- Restoration depth increased to 0.06mm on 1.5mm thick aluminum, indicating thickness dependence.
- Restoration depth decreased when marks were re-engraved, similar to steel.
Conclusions:
- The developed etching technique is highly sensitive for restoring obliterated engraved marks on aluminum.
- The thickness of the aluminum sheet influences the depth of restoration.
- The findings have implications for forensic analysis and material identification.
