Carbon steel, the most widely used engineering material, despite its relatively limited corrosion resistance used in large tonnages in marine applications, nuclear power transportation, chemical processing , petroleum production and refining, pipelines, mining, construction and metal-processing equipment. The main objective of the present work involved the study of the inhibitive properties of natural product as spearmint plant extract as a safety and an environmentally friendly corrosion inhibitor for low carbon steel in (3.5% NaCl) solution. Results showed when the immersion model in (3.5% NaCl) solution that contains the inhibitor with concentration of (15% in volume), it's getting decrease in lost weight , indicating a layer of adequate oxide on the surface of steel, indicating that the amount of loss weight decrease with increasing concentration of inhibitor and this shows the damper on his ability to form a protective layer .

The Al-Zn-Mg-Cu aluminum alloys are primarily used in the aerospace industry as structural components. This study aim to improve properties of Al-5.6% Zn-2.5%Mg-1.6%Cu such as impact toughness, thermal stability and corrosion resistance by using quenching in 30% polyethylene glycol and addition 0.1%Zr to this alloy. Results showed that the addition 0.1% Zr to base alloy improve impact toughness by (40%) when quenching in water, and by (60 %) when quenching in 30%PAG corresponding to the base alloy when aging at 150 °C. Also results showed that the thermal stability improved when we addition 0.1% Zr by (20%). An improvement of corrosion resistance when addition 0.1% Zr (B alloy) by (326 %), at aging time 150°C in comparison to the base alloy.