Tantalum is highly resistant to chemical corrosion and atmospheric corrosion under 150℃. Tantalum is stable to other acids except hydrofluoric acid, fuming sulfur trioxide and concentrated sulfuric acid and phosphoric acid at high temperature. TaW alloys are even more stable than gold and platinum in acidic and neutral media at 200℃.
Tantalum not only has the advantages of high strength, good stability and molding, but also has the stability and healing property with human tissue, which has no reaction to human tissue. Tantalum can be used as bone grafting material, screw, nail, suture needle and other surgical materials as well as dental instruments.
The anodic oxidation film of tantalum is red, yellow, green, blue, purple and other bright colors, which can be used for jewelry production. Tantalum has good chemical stability to liquid metal mercury, sodium and sodium-potassium alloy, so it can be used as liquid metal container and pipeline in atomic energy industry.
The surface - purified tantalum and tantalum alloys do not oxidize at room temperature in the atmosphere. At higher temperatures, oxidation occurs and surface color changes occur. The gray and black oxide film was produced by heating at 500℃ for a short time, which prolonged the holding time and turned the oxide film white.
The oxidation film formed at low temperature has a protective effect, which slows down the oxidation rate. Therefore, tantalum and tantalum alloy tubes, rods and wires can be directly cold-processed at room temperature, and the hot processing must be coated with anti-oxidation coating, or in a vacuum state or in an inert gas atmosphere (generally argon).
