The reason why magnesium cementitious materials are not resistant to water is that they will corrode. The inability of magnesium alloys to see water is a sign of corrosion. Some friends don’t like this corrosiveness, while some friends who do corrosion work like the corrosiveness of this material. When this material corrodes when exposed to water, the surface will Blackening occurs, followed by the formation of some small black spots. These small black spots do not affect normal use. It is normal for small black spots to appear when encountering water. Unless it is something with relatively high requirements, it is not allowed to come into contact with water. .