خواص فیزیکی نیوبیم و تانتالیم

Niobium has a grayish-white metallic luster, the powder is dark and looks like platinum; tantalum is gray and very heavy; both niobium and tantalum are quite hard and difficult to melt. Gold, which is "not afraid of fire", has a melting point of only 1063 degrees Celsius. Platinum, a popular high-temperature resistant metal, is completely melted when it exceeds 1769 degrees Celsius. However, the melting point of niobium is as high as 2400 degrees Celsius, and the melting point of tantalum is close to 3000 degrees Celsius. The plasticity of pure niobium is very good, and it can be rolled into a very thin sheet in cold state without intermediate annealing;