Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Joanna Wróbel "

The effect of structure on the stability of Al-Si coatings under salt mist conditions

Czytaj za darmo! »

The high corrosion resistance of Al alloys, as well as their sufficient heat resistance, have contributed to the use of these alloys for anodic protective coatings being applied on steels intended for, e.g., exhaust system elements. Developing coatings that would meet the ever-increasing operation parameters of cars is the subject of continuous research work. The new customer demands, technological solutions, and increasing car performance parameters are all urging the designers to use increasingly expensive steel grades with bettered mechanical parameters. However, a significant limitation on the wide application of stainless steels is the fact that, in spite of the absence of visible corrosion products, in acidified oxidizing media containing some anions, these steels undergo spontaneous, often localized dissolution. Due to the weight and economy of product, the basic element used for protective coatings in the automotive industry still remains to be aluminium [1÷4]. The problem of properly selected protective coatings is crucial in the manufacture of car exhaust silencers, because the whole exhaust system, in addition to mechanical damage during service, is exposed to aggressive chemical agents that accelerate the steel corrosion processes. At present, steels of a chromium content above 10% with an aluminium-silicon hot-dip coating applied are used for the manufacture of car exhaust systems. Exhaust system elements are formed in a stamping process. The main technological problem during their production from aluminium-coated steel sheet is to maintain the integrity of the coating. This problem has been partially solved by using silicon as an alloying element. However, it has been demonstrated in the author’s studies, that such coatings often exhibit an uneven arrangement and size of silicon crystals (as a result of the trade-off between the technical capabilities to produce a coating by the hot-dip coating method and th[...]

 Strona 1