摘要
犯罪现场中工具痕迹特征易受外界环境影响,特征增强复原是提高工具痕迹利用率的关键方法。为比较分析常见铝丝剪切痕迹腐蚀前后特征变化对检验鉴定的影响,采用中性盐雾加速腐蚀方式处理铝丝表面剪切痕迹,探讨物理和化学处理方法对铝丝表面腐蚀线条痕迹的影响。实验结果表明,腐蚀后的铝金属痕迹特征可通过物理或者化学修复方法改善其表面效果,实现同一认定的目的;化学修复优化工艺参数为VHCL∶VH2O为1∶2,酸洗时间30s;VHNO3∶VH2O为1∶4,酸洗时间40s;超声震荡清洗法工艺参数为控温30℃、频率40kHz、75%的乙醇介质条件下超声时间大于120s;细小线条特征稳定性差,容易受到外界环境的影响而损失,而宽度大于0.01mm的线条痕迹可通过物理/化学方法完整显现。实验结论在司法鉴定中可为铝金属物证的腐蚀表面处理提供技术支持和实践参考。
In the crime scene,as evidenceof the tool trace material is easy to be affected by the external environment and loses its characteristics,the enhancement and restoration of surface trace features is a key method to improve the utilization rate of tool trace.In order to compare and analyze the influence of the characteristic change of the common metal-aluminum wire shearing marks before and after corrosion on the inspection and identification,the cutting marks of aluminum wire were corroded by neutral salt spray,and the characteristics of the marks on the surface were analyzed.The effects of physical and chemical treatment methods on the traces of corrosion lines on the surface of aluminum wire were also discussed.The results show that the corrosion products on the surface of aluminum metal after being corroded block the trace characteristics of the lines,thus making the results of inspection and identification impossible,the process parameters of chemical repair for the trace characteristics on the surface of aluminum wire are:VHCL:VH2O=1:2,pickling time 30s;VHNO3:VH2O 1:4,pickling time 40s;The experimental temperature was 30℃,and the ultrasonic time in 75%ethanol medium was more than 120 seconds.The characteristic of line trace width≤0.01 mm is not stable,and it is easy to be affected by external environment,while the line traces with a width greater than 0.01 mm can be completely displayed by physical/chemical methods.
作者
王晓晨
李大武
WANG Xiaochen;LI Dawu(College of Forensic Science,Criminal Investigation Police University of China,Shenyang,Liaoning,110854)
出处
《中国刑警学院学报》
2023年第5期103-112,共10页
Journal of Criminal Investigation Police University of China
基金
2016年度上海市刑事科学技术研究院现场物证重点实验室资助课题(编号:2016XCW2K03)
2021年度公安部科技基础项目(编号:2021JC07)。
关键词
盐雾腐蚀
特征修复
氧化膜
工具痕迹
salt spray corrosion
feature repair
oxide film
toolmarks
