What Is Hard Chrome Plating?
Hard chrome plating is indeed an electroplating process used to deposit a layer of chromium onto a metal surface. The process typically involves submerging the workpiece, usually made of steel or other metals, into a chromic acid solution and applying an electric current to initiate the plating reaction. The thickness of hard chrome plating can vary depending on the application and requirements. It can range from as low as 2 micrometers (µm) to as high as 250 µm. Different thicknesses may be suitable for different purposes. There are several types of hard chrome coatings that are used based on specific needs:
Micro-cracked chromium: This type of hard chrome coating has tiny cracks throughout the plated layer. These cracks provide a path for lubricants to penetrate, allowing the coating to retain lubrication and reduce friction. Micro-cracked chromium coatings typically have a minimum thickness between 80-120 µm and exhibit high corrosion resistance. They also have a Vickers hardness of 800-1000 kg/mm2, which indicates their hardness and durability.
​
Micro-porous chromium: This type of hard chrome coating is achieved through a specialized plating method that involves the use of inert suspended particles. The particles create voids within the plated layer, resulting in a micro-porous structure. Micro-porous chromium coatings are designed to retain lubricants, making them suitable for sliding and bearing applications. The specific thickness requirements for micro-porous coatings may vary depending on the desired properties.
Porous chromium: Porous chrome plating is developed by etching the electrodeposited chromium layer. This process creates a porous structure that can retain lubricants effectively. The porosity allows the coating to hold and release lubricants during operation, making it suitable for sliding and bearing applications.
​
Crack-free chromium: This type of hard chrome coating is characterized by a lack of micro-cracks or porosity. It typically has a lower Vickers hardness ranging between 425-700 kg/mm2 compared to micro-cracked chromium. Crack-free chromium coatings are generally used when high hardness is not the primary requirement but a smooth and flawless surface finish is desired.
​
It’s worth noting that while hard chrome plating offers benefits such as improved wear resistance, corrosion resistance, and low friction, it can involve the use of toxic chemicals and pose environmental challenges. Alternative coating technologies and materials are being explored to address these concerns. Chrome plating is utilized for its tribological (low friction) properties as well as its ability to resist wear and corrosion. Nevertheless, concerns regarding the disposal of the plating solution have prompted numerous chrome plating users to explore alternative coating techniques. An alternative option is to substitute hard chrome with high velocity oxy-fuel (HVOF) sprayed coatings made of cermet materials like WC/Co (Tungsten Carbide/Cobalt). These HVOF sprayed coatings provide enhanced protection against wear and corrosion. The table below presents a comparison of properties between HVOF sprayed WC-12Co and hard chrome.
Most Frequently Asked Questions
Superior hardness: Hard chrome plating is harder than most other industrial abrasives and metallic coatings. Measuring between 68 and 72 HRC, hard chrome plating can withstand demanding industrial applications and high stresses.
Hard Chrome Plating Services in Local locations of Mumbai:-
Most common Cities in mumbai we delevered our services
Most common Cities in Gujarat we delevered our services
