Why are bath fittings coted with cromium?

Answer 1

Chrome plating (less commonly chromium plating), often referred to simply as chrome, is a technique of electroplating a thin layer of chromium onto a metal or plastic object. The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness. Sometimes a less expensive imitator of chrome may be used for aesthetic purposes.Chrome plating a component typically includes these stages:

• Degreasing to remove heavy soiling
• Manual cleaning to remove all residual traces of dirt and surface impurities
• Various pretreatments depending on the substrate
• Placement into the chrome plating vat, where it is allowed to warm to solution temperature
• Application of plating current for the required time to attain the desired thickness

There are many variations to this process, depending on the type of substrate being plated. Different substrates need different etching solutions, such as hydrochloric,hydrofluoric, and sulfuric acids(also called sulphuric acid ). Ferric chloride is also popular for the etching of Nimonic alloys. Sometimes the component enters the chrome plating vat electrically live. Sometimes the component has a conforming anode made from lead/tin or platinized titanium. A typical hard chrome vat plates at about 1 mil (25 µm) per hour.

Various linishing and buffing processes are used in preparing components for decorative chrome plating. The overall appearance of decorative chrome plating is only as good as the preparation of the component.[1]

The chrome plating chemicals are very toxic. Disposal of chemicals is regulated in most countries.

Some common industry specifications governing the chrome plating process are AMS 2460, AMS 2406, and MIL-STD-1501.