• HOME
• SERVICES
  • Plating Electroless Nickel / PTFE
  • Hard Chrome Plating
  • Tungstenite Dry Film Lubricant
  • Brazing Water Cooling Channels
  • Plasma Spray Coatings
  • Vacuum Heat Treating and Brazing
  • Physical Vapor Deposition
• ABOUT US
• ARTICLES
  • Tool Steel
  • Multilayer Pvd Coating
  • Tungstenite Dry Lubricant
• CONTACT US
• QUALITY POLICY

HARD CHROME PLATING

Electroplating made its debut in the early 1800's after the invention of the voltaic pile, or battery. Soon after, decorative coatings of gold and silver became commercially available. In the 1920's, chromium plating was introduced as a bright and lustrous coating that retained these properties, making it ideal for appliance and automotive applications. This led to the creation of hard chrome plating which provided a new form of wear resistance, low friction and worn part refurbishment.

PROCESSING
Chrome is applied from a solution containing chromic acid and catalysts. The part to be plated is immersed in the solution and connected to an electrical circuit. A small voltage in the circuit causes the chrome to deposit onto the immersed part from the solution. Anodes are placed near the surface of the part, where plating is desired, to improve the process. Hard chrome plating is used mostly as a wear resistant coating. With a hardness of approximately Rc 70, hard chrome can exceed the levels by such processes as carburizing, while imparting no distortion to the base part. Hard chrome is also quite lubrous, which makes it desirable for sliding components and plastic molds. Heavy build-ups of hard chrome are routinely used for refurbishing of worn parts, although this has more recently been replaced with plasma sprayed coatings on high strength materials which are susceptible to embrittlement from plating processes.

Although chrome plating is usually applied to ferrous surfaces, there are few restrictions on the materials that can be plated, or on their previous history. For example, softer materials may not be able to support the plated layer under loading, and casting integrity can affect deposit quality.

One problem with chrome plating usually not considered is its corrosion resistance. Although chromium itself is very oxidation resistant, due to inherent micro cracking in the surface of the deposit, corrosive agents can penetrate the plating layer and attack the substrate. For this reason, when corrosion resistance is required, a layer of electroless nickel is plated first, then over-plated with hard chrome.

COMPOSITION: 100% Chrome

COLOUR: Bluish - Silver

HARDNESS: Rc 68 - 70

THICKNESS: Typically .0001" - .030"

TOLERANCE: Varies with part geometry

UNIFORMITY: Varies with part geometry

PLATING RATE: .001" Per hour

COEFFICIENT OF FRICTION: 0.15

CORROSION RESISTANCE: 72 Hours (ASTM B-117 Salt Spray, .001")

WEAR RESISTANCE: 1.1mg/1000 Cycles, taber test