メダルは本物の金か？

Introduction

Nowadays, thousands of people pay attention to this question.

Why?

Because gold is a non-renewable resource and it’s very expensive. In the past, people will bite the medal, especially the champion to make sure it is real gold.

But now because of the high price of real gold, most of the medals are not made of full gold(including the Olympics), such as the 2008 Olympics medal, each gold medal contains no less than 6 grams of gold.

Normally, the material of the medal is zinc alloy, copper, aluminum, stainless iron, iron. To make them look like gold or silver, we will do the planting, and after planting medals looks like gold or silver medals.

What are the differences between these materials?

亜鉛合金

Advantages of Zinc Alloy
1. High plasticity 2. Recyclable recast
3. Anti-corrosion 4. Easy to operate
5. Suitable for plating 6. Low cost

The disadvantage of Zinc Alloy
Surface blistering

銅
Advantages of Copper
1. Wear-resisting 2. Chemical stabilization

The disadvantages of Copper
1. Expensive 2. Heavy

アルミニウム
Advantages of Aluminum
1. light                      2. Easy to operate
3. Large production            4. Oxidizing layers protect objects

The disadvantages of Aluminum
1. Low density                2. Easy to deformation
3. Not corrosion-resistant, not wear-resistant

ステンレス・アイアン
Advantages of Stainless Iron
1. Strong corrosion resistance 2. Large hardness, not easy to deform 3. Metallic

The disadvantage of Stainless Iron
Have burrs

鉄
Advantages of Iron
1. Have a good sense of hierarchy 2. Cheap

The disadvantage of Iron
錆びやすい

Different materials correspond to different molds and processes, zinc alloy medal needs a Square mold, there are small openings around the mold to facilitate the injection of liquid zinc alloy, which is then die-cast.
Other materials need a circular mold, factory workers use a loud press machine to strike the mold with 550 tons of force – three times – to create your medal appearance.