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The core of the corrosion reaction of hydrofluoric acid is due to its unique fluoride ion characteristics. Although it is a weak acid, it can corrode a variety of conventional acid-resistant materials such as glass and metal. The relevant reactions and mechanisms are as follows: 1. Typical corrosion reaction equation: SiO₂, the main component of etched glass (silica), will react with HF to generate volatile silicon tetrafluoride. This is also the core reaction of hydrofluoric acid etching glass.: SiO2+4 HF=SiF4↑+2 H2O This reaction is the basic principle of industrial cut glass and semiconductor silicon wafer cleaning. Corrosion of metals and alloys Hydrofluoric acid can destroy the protective oxide layer on the metal surface. Taking chromium-nickel alloy as an example, fluoride ions will react with chromium oxide to form a soluble chromium-fluoride complex, which will continue to corrode the base metal after peeling off the passivation film. 2. The unique role of fluoride ions in the core corrosion mechanism. The F⁻ radius in hydrofluoric acid is extremely small, the electronegativity is extremely high, and the coordination ability is much stronger than common anions such as Cl⁻ and SO₄²⁻. It can be directly adsorbed on the defects of the metal oxide layer and dissolve the protective layer by forming a soluble metal fluorine complex to prevent the reconstruction of the passivation film and cause continuous pitting corrosion. The size of the penetration characteristic F⁻ is smaller than oxygen ions and can penetrate dense oxide structures. The oxide layer barrier of ordinary acid-resistant materials cannot block its penetration. This is also the key reason why hydrofluoric acid can corrode conventional acid-resistant media such as glass and ceramics.