Yes if you want to cause a very big chemical reaction
Ships, flat bed trucks, and trains. Light tanks such as the Vietnam era M551 Sheridan (built of aluminum) could be transported by air.
The M551 Sheridan had an aluminum hull, but almost all tanks have had steel hulls.
By ship; civilian or military.
Most fuel tanks are made of steel or plastic.
helicopters and tanks.
They were typically transported by ship.
no it is made of steel not aluminum
No, tanks are too heavy to be transported by a helicopter. Some Light Armored Vehicles can be transported, but not a tank. There are a couple of commercial helicopters that have the lifting power to move a tank, but it is not military and it is lifted externally, not internally.
SCUBA tanks are metal (usually steel or aluminum) that are filled with compressed air. This is loosely related to a pneumatic system.
Steel has been used as a tank material since the begining of scuba diving. Extremely durable and useful as a tank material but steel rusts. Buy a steel tank, assume that over the life of the tank it will cost you for a few tank tumbles to remove interior rust. Pay more for a steel tank than an aluminum one. Steel will last (almost) forever if you take care of it. There are steel tanks still in service today that were originally manufactured in the 50s. Aluminium tanks came out in the 70s. It's a softer material, the walls of aluminum tanks are thicker, making them a little larger than steel tanks of the same capacity. The big advantage of aluminum is that it doesn't rust and it's less-expensive than steel. You can find aluminum tanks cheap, for $100-150.
Yes, any nitrogen tank is refillable.
It's an aluminum radiator with plastic tanks.