Azotic writes:

Those materials leak into the air as gases and combine with the
moisture on an air conditioning coil to create sulfuric acid, which
appears to be dissolving solder joints and copper tubing - creating
leaks, blackening the coils and even causing the system to fail.

Sounds like somebody trying to scapegoat the furriners. This problem has
been due to the AC manufacturers and long predates any Chinese imports:

http://www.google.com/search?q=evapo...cary+corrosion