The trivalent chromium black zinc passivation process has become a popular choice for galvanizing treatments in recent years due to its environmental credentials and low toxicity. However, despite its good corrosion resistance, it performs relatively poorly in terms of wear resistance. The causes of this phenomenon are mainly related to the physical properties, chemical structure and process control of the passivation film.
First of all, the thickness and structure of the trivalent chromium black zinc passivation film have a significant impact on its wear resistance. The passivation film is usually thin and mainly composed of a complex oxide layer. This film is susceptible to damage in the case of mechanical friction, leading to exposure of the substrate and subsequently accelerating the wear process. The lack of toughness and low hardness of the film make it difficult to resist sustained mechanical stress.
Secondly, the chemical reaction in trivalent chromium passivation is milder, resulting in a denser but more brittle passivation film. In contrast, hexavalent chromium passivation films, although less environmentally friendly, provide better wear resistance by virtue of their own structure. Due to the inherent brittleness of trivalent chromium passivation films, they tend to flake off under friction impact, exposing the underlying galvanized layer and making the wear resistance of the entire passivation system insufficiently secure.
In terms of process control, small changes in passivation time, temperature and solution concentration can lead to fluctuations in film consistency and quality. Improper handling of any of these factors may exacerbate defects in the passivated film, increase its brittleness, and lead to a further reduction in wear resistance.
In order to improve the abrasion resistance of trivalent chromium black zinc passivate films, optimization and improvement is required in several areas. Firstly, the toughness and hardness of the film layer can be improved by using Bigely trivalent chromium black zinc passivate. Secondly, process parameters can be adjusted to ensure film uniformity and thickness. In addition, multi-layer film structures or hybrid passivation methods can be explored to improve overall wear resistance.
In conclusion, although the trivalent chromium black zinc passivation process performs well in terms of environmental and corrosion protection, its poor wear resistance is mainly attributed to the physical and chemical properties of the passivation film. By using Bigely trivalent chrome black zinc passivate and optimizing the process, the wear resistance can be improved to a certain extent, thus widening its application range.
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