Began to apply iron of people for a long time. For many hundreds of years of property of this metal and its connections are well studied. In most cases in life and on production the people should deal not with pure iron, and with its various connections and alloys. All modifications of iron differ from each other in color.
Properties of iron
Iron represents, perhaps, the most typical of all metals. This material is very plastic. Impurity (in particular, carbon) give gland hardness, but do to more fragile. One of the main useful qualities of this metal – pronounced magnetic properties. Experts carry iron to metals with moderate refractoriness and average chemical activity.
Iron – was thrown by quite heavy. Mechanical properties of iron are in direct dependence on its purity. In the nature this metal meets in the form of ore.
In a free state iron possesses a silver-white shade, sometimes with grayish tones. Pure iron is practically not applied in production. Usually mean its alloys with other chemical elements by iron: depending on the content in alloy of carbon distinguish steel and a chuguna. Existence of third-party elements is capable to change chemical and physical properties of metal including its color.
Impurity and their influence on properties of iron
In the melted look iron is a mass of uniform liquid consistence which contains a number of impurity in the dissolved look. If to subject carbonaceous iron to long heating within a point of its melting, free carbon can be emitted. It inherently – graphite in a melkorazdroblenny state. Graphite has an appearance of dark stains or points which are shown on a metal break surface.
At a usual temperature and low humidity the oxygen which is contained in air does not affect iron in any way. If to begin heating, metal will begin to be oxidized and become covered by a film of magnetic oxide. Owing to features of light such film is gradually painted by all colors of the rainbow, from yellow to blue. And after that becomes livid scale.
A number of compounds of iron has the expressed brown color. In particular, it is about the almost insoluble connection known as iron oxide hydrate.
Iron rustiness
In the conditions of the increased humidity iron is oxidized. At the same time it is formed transformed derivative gland, called rust. Rust has rough friable structure and rather wide color range – from orange and to henna-red. At the same time metal grows dull. Process of formation of rust is called rustiness (corrosion).
The term "rust" is applied only in relation to products of rustiness of metal or its alloys.
Experts distinguish several types of rust and speak about "red" and "green" rust. The last look is quite often formed in fittings which find application in underwater concrete structures.