Electroplating of chromium is produced with the solution of chromic acid and small amount of sulphuric acid. The anode is an alloy of lead and tin. The cathode is the metal sheet or equipment on which chromium is deposited. The electrolytic tank is made of lead lined steel. The electrolytic process is started. The composition of bath is checked at regular intervals. Addition of chromic acid and sulphuric acid are made to maintain the composition of the electrolytic bath. Care is to be taken to prevent the contamination of impurities like copper, zinc and iron. The optimum temperature is between 40'C and 50'C. the solution is to be concentrated in nature to avoid concentration and to catalyze the decomposition. The bath may have high conductivity and less voltage is required. The chromium plating may be decorative with thin layer of chromium deposited on the metal surface. But in industrial application, the plating is hard and thick. In such case, chromium is directly deposited on the metal surface without any intermediate coating. The chromium electroplating has a number of applications. These are printing plates, wrist pins, steering knuckles, tube drawings, bearings, cylinder liners, piston rings, cutting tools and files.
Due to presence of impurities in the electrolyte the deposit may be rough. So impurities are to be removed before the start of the electroplating work. If the temperature is high then there is possibility of soft deposits. Even the deposits may look dull or milky. Embrittlement occurs due to presence of hydrogen. Pits are produced due to presence of gas bubbles. No deposition or slow deposition may take place due to bad electrical contact, low current density and low cathode efficiency. So,there must be sufficient care to tackle all these problems during electroplating of metals and equipments with chromium.