Studi pengaruh variasi penambahan serbuk alumunium paduan (A356.2) pada cat epoksi terhadap daya lekat dan ketahanan korosi pelat baja karbon ASTM A36 di lingkungan laut = Study of effect variation addition of aluminum alloy powder (A356.2) in epoxy paint on the adhesion and corrosion resistance of ASTM A36 carbon steel plates in marine environment