For oxide layer to be protective, the Pilling Bedworth ratio should be

Intergrannular corrosion of light 18-8 stainless steel can not be prevented by

A. reducing the carbon content to less than 0.05%

B. quenching it from high temperature to prevent chromium carbide precipitation

C. adding strong carbide forming elements

D. increasing the carbon content

Which of the following metals is highest noble in the Galvanic series?

A. Platinum

B. gold

C. graphite

D. titanium

Difficult to monitor and very dangerous form of corrosion

A. Galvanic

B. Pitting

C. Crevice

D. Stress

Based on the standard galvanic series, select the correct sequence of metals in the increasing order of anodic behaviour:

A. Zn, Fe, Pt, Cu

B. Pt, Zn, Cu, Fe

C. Fe, Pt, Cu, Zn

D. Pt, Cu, Fe, Zn