Non-ferrous, precious and ferrous types of metals and their characteristics

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Metals are a large group of simple elements with characteristic features such as high thermal and electrical conductivity, positive temperature coefficient and more. To properly classify and understand what's what, you need to deal with all the nuances. Let's try with you to consider such basic types of metals as ferrous, non-ferrous, precious, as well as alloys. This is quite an extensive and complex topic, but we will try to put everything on the shelves.

What everyone should know?

Before classifying metals into groups, it is necessary to understand the main features. The primary ones include the negative coefficient of conductivity of electricity. This suggests that as the temperature decreases, the conductivity increases, and some conductors become superconductors. At the same time, an increase in temperature leads to partialor complete loss of bandwidth. The secondary features include a metallic luster, as well as a high melting point. In addition, some metals in the form of compounds play the role of a reducing agent in redox reactions. Please note that pure metals are practically never found in nature, so you should not forget about ore and nuggets either.

About ferrous metals

This group includes iron, as well as its alloys (cast iron, ferroalloys). In fact, ferrous metals are an alloy of iron and carbon, but in addition to this, there are other chemical elements, such as sulfur, phosphorus, silicon, etc. which are most often copper, chromium or nickel. All types of ferrous metals are classified by carbon content. So, there are the following alloys:

• Cast iron - the amount of carbon ranges from 2 to 4.3%, in some cases reaching a critical level of 5%. Various chemical elements directly affect the properties of the product. So, sulfur with phosphorus increase brittleness, while chromium and nickel additives make cast iron more heat-resistant and resistant to corrosion.
• Steel - carbon content up to 2%. It differs from cast iron in high ductility, as well as high technological performance (easier to process).

Features of cast iron and steel in detail

Currently existsseveral types of cast iron that are used in everyday life, as well as industry: foundry (gray) and conversion (white). The latter differs from the first type in that carbon is in a bound state in the form of cement, in the first case - in a free state in the form of graphite. The decrease in the strength of this material is due to the fact that graphite plates break the metal structure, thereby weakening it. There is modified gray cast iron. Its features are that the graphite is in a spherical shape, which increases the mechanical properties of the product.

You probably already realized that they have become more versatile, due to not so much carbon in the composition. Thus, structural steels contain from 0.02 to 0.85% carbon and are used for construction. Their main advantage is good plasticity. The degree of brittleness is low. There are also instrumental ones, in which the carbon content is slightly higher - from 0.65 to 1.4%, therefore, it is a stronger alloy, but brittle. It is used, as the name implies, as a blank for creating tools (cutting, sawing working parts of machines and assemblies). Here we have looked at the types of ferrous metals, so let's go further.

Precious Metals

This group includes chemically stable alloys that do not oxidize in water and air. It is worth noting that the number of such metals on the entire planet is relatively small, and the process of extraction and processing is extremely complex and time-consuming. If for a long time mankind knew only about 7 groups, today there are several of them.more. So, the most famous types of precious metals: gold, silver, platinum, osmium, rhodium, palladium, iridium, etc. All of them are found in nature. There are also so-called isotopes. They are obtained in laboratories by complex chemical reactions. The most expensive such metal is californium-252, worth $500,000 per gram. Osmium-187, obtained in modern laboratories, is among the most in demand.

About silver and gold

Since the Stone Age, people have been familiar with such a metal as gold. It is safe to say that this is the most important precious metal in the world. In nature, it is most often found as nuggets with a small amount of impurities or in an alloy with silver. The exceptional features include thermal conductivity and very low resistance. Of course, one cannot fail to note the malleability of gold, which is why it is an extremely popular material for making jewelry. Interesting fact: the largest gold nugget was found in Australia. He weighed about 90 kilograms.

If we consider the main types of precious metals, then we can not say about silver. In nature, this material is found in native form (silver ore). But it is worth noting that the main production is carried out from complex ores, where there is relatively little silver, but deposits of such minerals are more common. It is a very soft and ductile metal that has exceptional electrical and thermal conductivity.

Rhodium and Platinum

Rhodium is a metal, nothaving its own minerals, therefore, is one of the most expensive. You will have to pay more than 220 dollars per gram. This noble metal has a silvery color with a bluish tint. It is distinguished by its resistance to chemical and thermal influences, but is extremely vulnerable to mechanical damage due to its fragility. Since it is quite expensive, it is used only where it is impossible to find an analogue.

If we consider the types and types of metals, then we can not say about platinum, discovered in 1952 by a Swedish chemist. This is a fairly rare material and is found in nature only in combination with alloys with other metals. The mining process is extremely laborious and requires large investments, but it is worth it, because no acid known to date affects platinum. When heated, it does not change its color and does not oxidize.

Types of non-ferrous metals

This group is the most in demand, since most of the materials are raw materials for the production of rolled metal. If we talk about the scope, then it is quite extensive, it is: mechanical engineering, metallurgy, radio electronics, high technology, etc. According to physical properties, there are the following types of non-ferrous metals:

• heavy (lead, zinc, tin, nickel, etc.);
• light (aluminum, titanium, magnesium, etc.).

According to this classification, there is metallurgy of light and heavy metals. It is no secret that absolutely any technique can be made from this group. Please note that for colorincludes all types of metal alloys, except for iron. Now let's move on.

Main types of heavy metals

To date, there are approximately 40 definitions of the concept of this group of materials. Among the distinguishing features is an impressive atomic weight, usually more than 50. From this we can conclude that everything that comes after vanadium (regardless of density) should be included in the list. But if another definition is used, then the determining parameter may be the density, which should be more than that of iron (8 g/cm3). In this case, the list will include: lead, mercury, copper, but tin will be behind the list. Today, the issue of environmental pollution by this group is extremely acute. This is due to the fact that many metals are used in heavy industry and end up in the ocean along with sewage. The main problem is the high toxicity of mercury, lead, cadmium. In addition, some types of heavy metals tend to accumulate in living organisms. So, due to mercury poisoning in 1977, there were more than 2300 victims.

Mercury, lead and cadmium

These are the most dangerous heavy non-ferrous metals. They are the main environmental pollutants. Mercury is a highly toxic metal for humans, it enters the ocean through the atmosphere and with sewage. When coal is burned in power plants, mercury compounds are released into the atmosphere and then fall into the ocean as precipitation. In addition, many freshwater and marine life accumulate in theira significant amount of mercury in the body, which more than once led to human poisoning, and even death.

Cadmium is a dispersed and fairly rare element that enters the ocean along with wastewater from metallurgical and ore-dressing industries. It should be noted that cadmium is present in the human body, but it is very small. In chronic poisoning, bones are destroyed, and anemia begins. As for lead, this metal in a dispersed state is found almost everywhere. Such types of metals, the photos of which we have given above, are excreted from the body, but rather slowly, so their excess causes serious he alth problems. Along with continental dust, approximately 25,000 tons of lead enter the ocean along with precipitation.

Note

As you can see, there are various types and properties of metals. Something is not dangerous at all, and every day we wear a silver cross and a gold ring on our hand. Radioactive substances can kill a person, so environmentalists around the world are trying to partly solve the issue of the release of hazardous metals into the ocean and atmosphere. Of course, it is very difficult to solve such problems, especially considering that most entrepreneurs do not make contact at all. Nevertheless, do not forget that without conductors, which also consist of metal, electrical circuits are impossible, and without iron there will be no cars and other things familiar to us.

We have not touched upon the group of so-called radioactive metals of Mendeleev's periodic table. Hereinclude: technetium, polonium, promethium, etc. The main purpose is the use in nuclear reactors and weapons, which makes them very dangerous.

Conclusion

You must have noticed that there are many different types of metals. In nature, most of them are present in the form of ores and form various sulfides, carbonates and other chemical compounds. To obtain pure metals and their further use, modern technological cleaning and enrichment lines are used. Surely you will be interested to know that the human body also contains a small amount of metal compounds - about 3%. So, we have calcium in the bones, iron in the blood, magnesium constantly accumulates in the muscles, and there is copper in the liver.

Well, that, in principle, is all that can be said about what types of metal alloys exist. Despite the fact that this is a rather complicated topic, it may be of interest to those who are fond of metallurgy.