August 2017 Archives

Technologies used for forming ceramic films on metal substrates include plasma spraying and PVD. This ceramic plating is classified as a form of wet plating and a technology where the ceramics are electrocrystalized and sintered on a metal substrate. Using the term "plating" for this method could be a little awkward. However, since the principle of forming ceramic films on the anode metal by energizing it in the aqueous solution is similar to that of electroplating, it is referred to as "ceramic plating".

Metals that are compatible with this plating method are those that can form passive films by being energized in the electrolyte, such as aluminum, magnesium, and titanium. To be able to use them for plating, these metals must be anodized.
Using silicate salt for the electrolyte solution is another important factor to remember. The anode surface becomes passivated by the electrolysis, followed by electrification and plasma discharge. The silicate attracted on the anode will be sintered and then turned into ceramic.

Adhesion properties of the deposited films are excellent. In addition, the films are superior in heat resistance and rated well on corrosion resistance. Since the films can be colored while they are resistant to bending and work well with the post-processing, ceramic plating is adopted for various applications, from decorative items such as high-end wall materials, kitchen items to functional applications including the products utilizing characteristics as far-infrared properties, resistance to ultraviolet rays and radiation, and vacuum-proof properties. It is estimated that the film can be deposited for up to 50 um.

Plating consisting of copper, nickel, or silver can be directly applied on ultrafine particles (grain radius of roughly 10 um) that are made of iron, tungsten, mica, glass spheres, graphite, and alumina ceramics.

The applications include conductive metalized paste used for circuit formation on the ceramic boards, sintered alloy, IC packaging, electromagnetic shielding materials, anti-corrosive fillers, heat resistance enhancers, wear and sliding resistance materials, magnetic materials, and more.

Plating can be applied on fibers, including polyester, acrylic, carbon, cotton, and paper.

The applications of plated fibers include equipment using DC power supplied from batteries or solar cells, such as localized hot patches for medical use, electric blankets, carpets, heater panels for pets, cold protection gear and work clothes for cold weather.

In recent years, they are also adopted for electromagnetic shielding aprons and wallpapers protecting computer operators from the electromagnetic interference.

This volume introduces a new plating technology that used to be considered impossible.

Plating on functional glass

Electroless plating can be applied directly on silica glass and borosilicate glass (PYREX), in order to bond them with other metal and ceramic materials and to form an electric circuit or electrodes on the surface, while taking advantage of the characteristics of functional glass. Plating on the glass surfaces used to be done by dry plating, such as vacuum deposition and sputtering. However, its high cost and poor adhesion performance were the problem.
In this new plating technology, the glass surface and the plating film are chemically bonded, instead of going through the etching process where the adhesion between the glass surface and the plating film is enhanced by the anchor effect.
After rinsing and moisturizing the glass surface, the surface is treated with processes to enhance the chemical bonding. After the catalytic activation, electroless nickel plating is applied.
Then, various types of electroplating or electroless plating are applied depending on the usages.
The application examples include a pressure sensor using the PYREX glass tubes coated with nickel-gold plating inside and out, and the outer surface of a communication quartz optical fiber coated with electroless nickel plating in order to prevent light diffusion and noise generation.