Other Relevant Properties of Zinc

As already indicated, the choice of zinc or of particular zinc alloys or coatings often depends on factors other than corrosion resistance. The main properties are given in Zinc Handbook (Porter, 1991), but particular attention is drawn to several important or unusual properties. 

With respect to abrasion resistance, hot dip galvanized coatings are at least four to five times as good as pure zinc and most zinc-rich paints. The zinc-rich paints themselves are, however, more abrasion resistant than most conventional paints. 

unlike most paints, can be left in place on the faying surfaces of a bolted joint. This property, together with the use of zinc-coated steel fasteners, ensures that the Joint is fully protected. The initial lubricity of the coating is 

Slip in bolted joints has been investigated, and with dynamic loading it is shown that lock-up occurs after a few cycles, confirming the suitability of friction-grip joints in zinc-coated steel structures. 

Above a certain impact energy, contact between aluminum (and other light metals such as magnesium or titanium) and rusty steel can cause sparks capable of igniting combustible mixtures of gas and air such as are found in coal mines. 

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