Tantalum has a boiling point of 5427 ℃ and a melting point of 2996 ℃. It is a refractory metal, and its melting point is higher than that of other commonly used metals. Tantalum will react with oxygen at 300 °C in the air, nitrogen at 700 °C, and 350 °C in hydrogen-containing gas.，which  starts to react with hydrogen at 350 ℃ in hydrogen-containing gas, and starts to react with nitrogen at 300 ℃ in ammonia gas, and brittle compounds will be formed. Therefore, if tantalum equipment and containers are exposed to air during operation, the operating temperature should generally not exceed 250 °C. If they are not in contact with the environment such as air, it can be considered whether they can be used at higher temperatures. The welding and heat treatment of tantalum should be carried out in vacuum or under the protection of inert gas, that is, the thermal process above 300 ℃ should be carried out under the protection of vacuum or inert gas. Tantalum is commonly used in inert gas shielded welding, and the purity of argon gas should not be lower than 99.999%. Not only the welding pool should be protected by inert gas, but also the welding seam and heat-affected zone during cooling after welding should be protected by inert gas when the temperature is above 250 ℃. Therefore, a protective tow cover is required. It is best to stop supplying inert gas when the temperature drops below 200 °C. It should be ensured that the surface of the welded joint and each weld is silver-white or light yellow. The light blue should be ground off and no dark blue, off-white or white powder should appear.

Tantalum is mainly used as a corrosion-resistant material. Ta 2 O 5 film is formed on the surface of tantalum, which has good corrosion resistance. Generally speaking, the corrosion resistance of tantalum is better than that of titanium, zirconium and niobium, and it can be considered as the engineering material with the best corrosion resistance. It often has excellent corrosiveness in strong corrosive media such as nitric acid, aqua regia, hydrochloric acid, phosphoric acid, and organic acid, but it cannot be considered that tantalum can resist corrosion in any corrosive media, For example, in some temperature and concentration of fuming sulfuric acid, hydrofluoric acid, hydrosilicic acid, fluorosilicic acid, fluoroboric acid, sodium hydroxide, potassium hydroxide, potassium nitrite, aluminum chloride, aluminum fluoride, chlorine, bromine (in methanol) and other medium solutions, they have been used or tested with poor corrosion resistance or corrosion resistance. Tantalum and tantalum alloy pressure processing materials can adopt the brand of vacuum arc or vacuum electron beam melting and the brand of powder metallurgy. Due to the unstable mechanical properties, low plasticity and poor welding performance of powder metallurgy products, they are generally not used in pressure vessels, but only in the fluid parts of fluid machinery.

Tantalum and tantalum alloys have been widely used in pressure vessels, but there is no specific content in the official pressure vessel standard specifications of various countries. Pure tantalum is mainly used for pressure vessels, which has good corrosion resistance and plasticity. Ta-2.5W and Ta-10W tantalum alloys are used only when higher strength is required. 

Oxygen, nitrogen, hydrogen and carbon in tantalum can form an interstitial solid solution in tantalum. When the content exceeds the solubility, a second phase will appear, reducing the plasticity of tantalum. The addition of tungsten to tantalum will increase the melting point of tantalum and increase the high temperature strength of tantalum.