Episode2:Some extensive knowledge about “plating”

The history of plating

It all began 3500 years ago!

Plating was begun a very long time ago, in around 1500 BC. It appears that in Assyria in the northern part of Mesopotamia (currently Iraq) at around this time, metal was being plated with tin to prevent corrosion. In around 700 BC, nomadic people of Eastern Europe were using the “amalgamation process” to perform the gold-plating of bronze. In China, there are records remaining of the gold-plating of bronze ware in around 500 BC.

画期的な「電気めっき」の登場!

A major turning point in the long history of plating was the arrival of electroplating (electrolytic plating).

The voltaic cell devised by the Italian physicist Volta in 1800 made it possible for humans to put electricity to practical use. These achievements are commemorated with the use of Volta’s name in the words voltage and the “volt” units used for potential difference.

Electroplating was invented in 1805, five years after the birth of the battery. The arrival of electroplating led to the development of various methods for plating metals and the applications for use increased greatly from the conventional use for rust prevention and decoration.

With the development of generators that could realize stable power generation, it became possible to support the mass production of machinery components and other items and the scope of the use of plating expanded even further.

The beginning of “chemical plating” was for mirrors!

The beginning of chemical plating (electroless plating) was the silver mirror reaction developed in Germany in 1835 to deposit silver on a glass surface. Mirrors are basically produced with that same method to this day, so the history of chemical plating is actually carved into this most familiar item that we look into each morning.

At the beginning of the 20th century, copper began to be used with the same method as the silver (mirror reaction). Then, in around 1946, the “electroless nickel” that is the most widespread chemical plating of today was invented in America.

The plating of Japan

Introduction together with Buddhism

In Japan, plating technology was introduced from the continent together with Buddhism in the late Kofun period in around 700 AD, when plating began to be used on horse harnesses and other items. After this, it went on to be used on items such as statues of Buddha, ornaments and swords. Of course, the plating at this time was performed with the amalgamation method using mercury.

“Electroplating” did not come, however, until a much later era, at the end of the Edo period. It is said that the first use of it was for the decoration of armor helmets by Shimazu Nariakira, who the feudal lord of the Satsuma clan.

The glitter of the great statue of Buddha at Todaiji Temple is a gift from plating!

The great Buddha (Rushanabutsu) that was completed in 752 at Todaiji Temple was made with plating technology that was the state-of-the-art at that time. The enormous 15 meter high statue of Buddha was divided into eight sections and cast in bronze in stages. After the whole statue was completed, gold was plated on the surface. The method used for the gold plating was to mix gold and mercury into an amalgam and paint it onto the surface. This was then heated with a charcoal fire so that the mercury evaporated and just the gold remained. It took as long as five years to gold plate the entire massive Buddhist statue.

We can only imagine how surprised the people of the time would have been when they saw this massive statue of Buddha. Plating played a very big role in the establishment of Buddhism in Japan.

Sayings about plating in Japan

“Plating will peel” in Japanese

This is used with the meaning that the true form that is hidden will be revealed. It seems that this saying came about because the plating of old very easily peeled off. However, the plating of today is much less likely to peel off, so it is much rarer for the true form to be revealed. If we were to interpret the meaning in a more modern way, it might be that “something that very rarely happens occurred.”

“True gold is not plated” in Japanese

If something is real gold, then there is no need to plate it. In other words, this is used to mean that if somebody really has ability, then there is no need to strive after effect.

Obviously, there is no point in plating gold onto gold. However, today we have various types of functional plating and plating is used to expand the possible applications of the original material and raise its value. We might even be able to create a modern saying that “plating is never a waste.”

The plating of today is judged not only for its appearance, but also for its contents!

As is shown in these sayings, the applications for plating in the past were mostly “decorative plating” using the beauty to the eye.

Of course, plating is still used in many different situations for decorative beauty and to prevent corrosion. However, the true worth of plating is proven with “functional plating.” More than for its appearance, the plating of today is proving useful for the various contents (functions) it offers. If a new saying were to be created today, plating would no doubt be used with a completely different image.