Electro‐plating technique and pH value

THE primary purpose of surface treatment by electro‐plating is to provide the material with a durable protective coating as a safeguard against corrosion. The coatings chosen for this purpose depend upon the type of metal to be protected and upon its chemical, thermal and mechanical properties. In all cases it is essential that the deposited coating be thick and uniform. In no circumstances may the coating be porous, otherwise the whole purpose of the protective layer would be defeated, resulting in increased corrosion owing to the effect of local action. Coatings virtually free from pores can only be produced by subjecting the working process to the strictest control and by paying due attention to those factors which may influence the desired result. These factors include temperature, current density, concentration of solution and finally the maintenance of the most favourable pH value. The determination of the hydrogen ion concentration (pH measurement) has been long recognised as an important aid in countless chemical researches; pH measurement is used for the control of raw materials, the manufacturing process and the finished goods. Due to the simple nature of the equipment used and the extremely convenient method of operation, pH measurements are eminently suitable for sampling or production control purposes.