Tantalum is an excellent corrosion resistant material, its corrosion resistance is better than titanium zirconium, comparable to glass, in addition to fluorine, hydrofluoric acid, acid solution containing fluoride ion, fuming sulfuric acid and strong alkali, tantalum is not corroded in most media. Specifically, in sulfuric acid, nitric acid, hydrochloric acid, aqua aqua, perchloric acid, chloride, bromide, hydrobromide, phosphoric acid; In nitrogen oxides, chlorine oxides, hypochlorous acids, organic acids (including chloroacetic acid); Among all salts that do not produce free hydrofluoric acid or strong base in hydrogen peroxide and hydrolysis, tantalum has very good corrosion resistance. Tantalum and its alloys (e.g. Ta2.5W, Ta7.5W, Ta10W, Ta40Nb, etc.) are more resistant to high temperature and mineral acid corrosion than many materials.
Tantalum has the advantages of high strength, good stability and good formability, as well as the stability and healing properties of human tissues. It is not responsive to human tissues, and can be used as bone setting materials, screws, nails, sutures and other surgical materials, as well as dental instruments.
Tantalum's anodic oxidation film is red, yellow, green, blue, purple and other bright colors, which can be used in jewelry making. Tantalum can be used as liquid metal containers and pipes in atomic energy industry because of its good chemical stability to liquid metal mercury, sodium and sodium-potassium alloys.
The surface purified tantalum and tantalum alloys will not undergo oxidation at ambient temperature (no color and weight gain changes). As the temperature rises, oxidation occurs and surface color changes occur. Gray black oxide film is produced by short time heating at 500℃, which extends the heat preservation time and turns the oxide film white. The oxidation film formed at low temperature has a protective effect, which slows down the oxidation rate, and destroys the protective oxidation film at high temperature, which accelerates the oxidation rate. Therefore, tantalum and tantalum alloy tubes, bars and wires can be processed directly at room temperature by cold, and hot processing must be carried out with anti-oxidation coating, or in a vacuum state or in an inert gas atmosphere (usually argon).
