Those materials which have dull appearance are said to have no lustre. For example: paper, wood, chalk, cotton, plastic, rubber ,cardboard etc. If we press a piece of iron nail with our hands ,we will find that it cannot be compressed at all. A piece of iron cannot be cut ,bend or scratched easily.
Iron is a hard material. If we press a piece of sponge between our hands, we will find that it can be compressed easily into a smaller size.
A piece of sponge can also be cut ,bent or scratched easily. Sponge is a soft materials. All the materials can be divided into two groups on the basis of their hardness or softness:.
Those materials which cannot be easily compressed cut ,moulded or scratched are called hard materials. For example: Iron ,steel ,wood, stone ,brick, glass ,bone ,teeth, diamond. Those materials which can be easily compressed cut, moulded or scratched are called soft material. For example: Sponge, cotton, wool ,foam, rubber ,candle wax ,butter ,chalk, clay ,feathers, flour, skin etc.
All the materials can be classified into two groups on the basis of their solubility. Sugar is a material which is soluble in water. Some materials which are soluble in water are common salt ,sugar ,washing soda, potassium permanganate, copper sulphate, alum, milk ,lemon juice ,alcohol ,glycerine etc. Water containing a dissolved material in it is called sugar solution.
Water having sugar dissolved in it is called sugar solution. Sand is a material which is insoluble in water. Materials which are insoluble in water are chalk powder ,saw-dust , sulphur, glass, plastic ,paper, floor, wax ,mustard oil , groundnut oil ,coconut oil, kerosene and petrol.
Add some glycerine to it. Materials which are soluble in water are use vinegar ,alcohol, milk, lemon juice. Add some mustard oil to it. Allow it to show it to stand for few minutes and observe. Water being heavier forms the lower layer in the test tube whereas mustard oil being lighter, forms the upper layer in the test tube. Some other liquid material which are insoluble in water are groundnut oil ,coconut oil, kerosene ,petrol etc.
Some gases are soluble in water whereas other gases are insoluble in water. Oxygen gas dissolved in water. The plants and animals which live in water use the oxygen dissolved in water for respiration.
Oxygen gas dissolved in water is very important for the survival of animals and plants that live in water. Carbon dioxide gas is also soluble in water.
The plants which live in water use the carbon dioxide dissolved in water for the process of photosynthesis. An understanding of material science is essential for power plant personnel to understand why a material was selected for certain applications within their facility. Almost all processes that take place in the nuclear facilities involve the use of specialized metals. A basic understanding of material science is necessary for nuclear facility operators, maintenance personnel, and the technical staff to safely operate and maintain the facility and facility support systems.
Our goal here will be to introduce material engineering of nuclear reactors. The knowledge of thermophysical and nuclear properties of materials is essential for designing nuclear power plants.
A material is defined as a substance most often a solid, but other condensed phases can be included that is intended to be used for certain applications. There are a myriad of materials around us — they can be found in anything from buildings to spacecraft. On the basis of chemistry and atomic structure, materials are classified into three general categories:. Metal is a material usually solid comprising one or more metallic elements e.
The unique feature of metals as far as their structure is concerned is the presence of charge carriers, specifically electrons. This feature is given by the nature of metallic bond.
In metallic bond, the atoms do not share or exchange electrons to bond together. Instead, many electrons roughly one for each atom are more or less free to move throughout the metal, so that each electron can interact with many of the fixed atoms.
The electrical and thermal conductivities of metals originate from the fact that their outer electrons are delocalized. In addition, composites are composed of at least two different material types. Another materials category is the advanced materials that are used in high-tech applications, including:. Materials Science.
We hope, this article, Classification of Materials , helps you. There are sub-classification for these categories are also available. Follow this tree diagram to understand the subclassification of materials. Before going into the topic it is necessary to understand the periodic table. The periodic table is a tabulation of the chemical elements according to their atomic number and electron configuration. In this periodic table, All the metals are listed on the left side and the non-metals are listed on the right side of the table.
Read more about periodic table here. Metals have good electrical and thermal conductivity and capable of malleable able to be hammered or pressed into shape without breaking or cracking.
In periodic table out of elements, 90 are metals only. See the periodic table for the metals. Examples of metals are steel , iron, copper, aluminium, zinc, silver, lead, etc. These are all alloys of metals.
Ferrous metals are rich in iron. Iron such as cast iron wrought iron, steel is the main constituents in ferrous metals. Ferrous metals are magnetic and capable of little resistance to the corrosion too. Examples for ferrous metals are cast iron , carbon steels , alloy steels , stainless steels , tool steels and die steels.
These metals have lightweight, high conductivity, corrosion resistance and non-magnetic properties are the specialities of non-ferrous metals. Some amount of iron will be added in some of the Non-ferrous metals but it is not a considerable amount. Non-Metal is referred to the chemical elements which are volatile, insulated to heat and electricity and lack of the metallic attributes.
Most of the non-metals are gasses. In the periodic table, they are represented under Polyatomic nonmetal, Diatomic non-metal, Noble gases.
0コメント