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元素周期表中Ⅳ至ⅦB族元素都是熔点较高的金属—钛、锆、铪、钒、铌、钽、铬、钳、钨、锰、锝、铼—常称为难熔金属。这些金属的抗蚀性都比较好,而钽(Ta)在抗蚀性方面更处于其中最前列。在150℃以下,能侵蚀钽的化学介质只有氟、氢氟酸、三氧化硫(包括发烟硫酸)、浓缩强碱和某些熔盐。钽在抗蚀性方面几乎可与玻璃相比,但它比玻璃耐高温,而且具有一般金属共有的便于加工的优点。
Groups IV to VIIB of the Periodic Table are metals of higher melting point - titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, pliers, tungsten, manganese, technetium, rhenium - often referred to as refractory metals. The corrosion resistance of these metals are better, and tantalum (Ta) is more in terms of corrosion resistance in the forefront. At 150 ° C, the only chemical medium that can attack tantalum is fluorine, hydrofluoric acid, sulfur trioxide (including fuming sulfuric acid), concentrated alkali and certain molten salts. Tantalum is nearly comparable in terms of corrosion resistance to glass, but it is more temperature-resistant than glass and has the advantage of being easy to process in common with metals.