Outdoor Patio Umbrella Canopy,Outdoor Umbrella Canopy,Canopy Umbrella With Base,Patio Umbrella Canopy Hebei Charlotte Enterprise Co., Ltd. , https://www.hbcharlotteawning.comSuzhou Education Edition Elective Four Topics 1 Unit 3 "Corrosion and Protection of Metals" ppt Course Standard Navigation 1. Understand the causes of electrochemical corrosion of metals. 2. Understand the hazards of metal corrosion and the general methods of metal protection. 1. Electrochemical corrosion of metals Metal corrosion (1) Definition: The phenomenon of corrosion or loss of metals or alloys with substances in the surrounding environment. (2) Essence: metal _______ electron is ______.