The Chemical Process Involved in Galvanizing Metal for Rust Resistance

Introduction

A method by which zinc is encased over corrosive metals is known as galvanizing. The galvanizing method is actually a procedure of coating corrosive metals, such as iron alloy and iron, with a non-corrosive metal. Zinc is dissolved and directed, generally by what's known as a warm drop, to the metal, supplying a outer layer of corrosion defence from one mil to just over four mils thick. When healed, the zinc, through answer with the coated metal, becomes zinc carbonate. (C. Porter, pp. 113-119)

LET US NOW LOOK AT THE PROCESS OF GALVANIZING

The current process that is most commonly used in Australian galvanizing operations is “dry galvanizing” which is best suited both environmentally and in terms of this paper, for paint and powder applicators.

With galvanizing, the surface preparation contains its own built-in means of quality control in that zinc will not react with the steel surface unless it is perfectly clean. Any failures or inadequacies in surface preparation will be immediately apparent when the steel is withdrawn from the molten zinc and any uncoated areas remain, and immediate corrective action can be taken. (Hubert, pp. 89-99)

STEP ONE:

Caustic cleansing - The work is put on beams or jigs and is manually loaded. This is to allow numerous products to be handled and processed simultaneously and then immersed in hot alkali solution which is generally heated to around 90 degrees Celsius and is used to remove organic contaminants like dirt, paint marking, grease and oil from the metal surfaces. Epoxies, vinyls, previous powder coating systems must be removed by mechanical cleaning such as shot or sand blasting. (Hubert, pp. 89-99)

STEP TWO:

Pickling - Scale and rust are removed by placing the work in a dilute solution of hydrochloric acid at an ambient ...