Brass: composition and properties of the metal, how to distinguish it (48 photos)

Brass is a metal material based on copper and the alloying component zinc. The alloy may contain lead, iron, nickel elements. Tin is sometimes present, but in small quantities. According to the metallurgical table, brass does not belong to the bronze group.

Story

The chemical element zinc was discovered in the 16th century, but the yellow metal was well known to humanity for many centuries before that time. The ancient peoples who lived in the southern Black Sea region combined copper with smithsonite, zinc ore, to produce a brass alloy.

During the time of the Roman politician Augustus, brass was called “orichalk,” which literally means “golden copper.” The yellow metal is similar to gold; ancient Roman coins were printed from it, jewelry and household items were made from it.

At the end of the 18th century, the English scientist D. Emerson obtained brass by alloying copper with industrial zinc. He patented the method and received a British patent. In the 18th century, before the widespread use of brass in metallurgy, it was used to counterfeit gold in Western Europe and Russia.

Ruthenium

10 most expensive metals in the world
A chemical element of light silver color, characterized by hardness and brittleness. One of the rarest elements of the platinum group. It was first discovered by Karl Klaus, a professor at the University of Kansas, in 1844. Used in jewelry, chemical industry, electronics. The price per troy ounce is $42.

Main characteristics of brass

Brass combines the positive properties and advantages of constituent metals. Metallurgists use the material in industry to improve the properties of metals, which together are stronger than individually. The yellow metal is resistant to corrosion processes, has increased strength, and can remain in aqueous and alkaline solutions for a long time without destruction.

Extraction and processing

Obtaining valuable substances is a labor-intensive and economically expensive process. Their content in the earth's crust is insignificant and in their pure form they are extremely rare.

After mining, the ore is sent to a non-ferrous metals plant for processing. Despite the complexity of the beneficiation processes and subsequent production of blanks, in a number of properties all types of non-iron materials have no analogues, which explains their popularity.

The method of processing non-ferrous metals depends on the substance from which they are composed. The main technologies include:

pressing;
punching;
rolling;
drawing;
forging.

Chemical properties

The structure of brass is formed by two classical components - zinc and copper. In the traditional version, the share of copper does not exceed 70%, and zinc – 30%. Several grades of technological brass have been developed, in which the zinc content is lower, only 48%. In the metals industry, nearly half of all zinc used is recovered from waste and recycling.

There are two types of brass, with differences in internal structure and chemical composition:

alpha type (single-phase), zinc content 35 percent;
alpha-beta type (two-phase), in an alloy of 50% zinc and 6% lead.

In terms of external characteristics, brass is similar to some brands of bronze, but does not belong to bronze materials.

Special grades of brass alloys contain small amounts of tin. It is used as an alloying component to improve the properties of the metal. In addition to tin, the chemical composition of brass may contain lead, nickel, manganese and other metals that can improve the characteristics of the material.

What is considered non-ferrous metal?

The first level of division of metals is into ferrous and non-ferrous.

There are no problems with black ones: these are iron and its alloys (cast iron, steel).

People of color are ranked differently. Sometimes all metals except iron and its alloys are considered as such (the list includes noble, rare earth, radioactive).

Industrialists have their own classification. Non-ferrous metals are iron-free elements of a certain color shade (hence the name of the group).

Divided into two types:

Heavy - zinc, copper, tin, lead, nickel.
Lightweight – aluminum, magnesium, titanium.

In a number of countries, such metals are called non-ferrous rather than non-ferrous.

The abbreviated name of the segment of non-ferrous metals is non- ferrous metal , ferrous metals - ferrous metal .

Physical properties

The characteristics of brass depend on additional alloying elements added to improve process parameters. For example, the density value varies in the range of 8300-8700 kg/m3.

The main physical properties of brass are:

the specific heat capacity when heated to 20 C is 0.377 kJ kg−1 K−1;
electrical resistivity 0.07*10−6 Ohm m;
is not ferromagnetic and does not acquire magnetic properties when exposed to critical temperatures;
the melting point averages 900 degrees;
high resistance to corrosion and destruction;
durable;
plastic,
good for forging and processing;
resistant to temperature changes.

Brass, as a conglomerate of several metals, has a weak conductivity of electric current. Composite metals create distortion in crystal lattices. The resulting voltage fields form the resistivity. Copper itself is an excellent conductor of electric current, which is why all wires are made of copper.

The melting point of brass alloy depends on the percentage of zinc. The more zinc, the easier it is to melt brass.

Rolled brass metal is well suited to arc and gas welding. Well polished and rolled. Resists weathering better than pure copper.

Additions of bismuth and lead to a brass alloy reduce the elastic properties of the metal, making it brittle when exposed to high temperatures (at 500 degrees).

Category: question - answer

What causes allergies to white gold?

Expert opinion

Kibantseva Elena Anatolyevna

Allergist-immunologist, “Movement” clinic, Saratov

The precious metal is absolutely hypoallergenic. An allergic reaction can only occur if low-quality impurities, such as nickel, are present. Rashes can also be the result of a skin reaction to detergents. During water procedures and cleaning, jewelry must be removed. Characteristic marks may remain due to increased sweating and hormonal disorders. Redness often appears on the hands, on the places of bracelets and rings. Perhaps the jewelry is simply small in size and rubs the skin.

Is it possible to wear yellow and white gold at the same time?

Expert opinion

Maria Baranova

Fashion designer

If you wear jewelry made from different types of gold together, then nothing bad will happen, the main thing is to do it stylishly. In addition, paired jewelry is made from both alloys. For example, it is not forbidden to wear a white cross on a classic gold chain, although it looks inharmonious.

Influence of constituent elements

To expand the range of uses of brass and improve its properties, alloying components are added to the alloy. Each component element has a specific effect:

silicon reduces the hardness value, making the material less durable, but resistant to wear during prolonged friction;
manganese increases strength and corrosion resistance;
tin, aluminum and iron in small proportions are added to the alloy along with manganese to improve strength values;
Lead has almost ceased to be added as an alloying element; it reduces the mechanical properties of the alloy, impairs ductility and elasticity;
nickel increases corrosion resistance and makes it possible to use the metal in alkaline environments;
aluminum, aluminum oxide creates a protective coating on the surface of the metal, which prevents oxidative processes from having a destructive effect;
Tin is a light metal; its addition improves strength and corrosion resistance.

The alloy with tin is widely used to create components for ships that constantly operate in seawater conditions.

Platinum

Platinum
It is used not only for making jewelry, but also for medical and industrial purposes. In the past, the metal was considered low quality silver and was often used to make “fake” jewelry. The main deposits are located in Russia, the USA, China, South Africa and Zimbabwe. Depending on quotes, a troy ounce of platinum costs from $1,100 to $1,300.

Production methods

Brass is one of those conglomerates that lend themselves well to processing methods - forging, stamping. At a low melting point, the metal exhibits good fluidity properties, due to which it is widely used in foundries.

When melting brass, zinc actively evaporates.

In the metallurgical industry, brass is mined in special refractory containers (crucibles) and in smelting furnaces, in which heat is transferred by radiation from the gaseous products of fuel combustion. In furnaces, melting occurs in a short time and with economical energy consumption.

California-252

California-252
The price of a troy ounce of metal is 775 million dollars!!! Only 30-40 micrograms of the element are extracted annually, which explains its high price. Since its discovery in 1951, only 8 grams of the metal have been mined in California. California is produced by only two laboratories in the world - 252, these are the Oak Ridge National Laboratory in the USA and the Russian Dimitrovgrad. It is actively used in medicine and nuclear physics. The most expensive element is also used to detect oil, gold and silver.

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Application areas of the alloy

In ancient times, brass was used in jewelry because of its similarity to natural gold. Thanks to its plasticity and good malleability for forging, coins were printed from it, jewelry and cases were made.

Brass alloys are improved by adding other metal components in order to improve the characteristics of rolled metal and expand the possibilities of its use in aggressive environments (in shipbuilding, in chemical shops).

In construction

Yellow metal has long established itself as a valuable material for creating parts for plumbing, pipes, appliances, and for the construction of various structures. Made from yellow metal:

fasteners (bolts and nuts, pipes, stamped parts);
products for heating engineering structures, instruments, equipment, condenser pipes;
plumbing parts (faucet mixers, couplings, tees, fittings);
furniture fittings (door handles, brackets, door hinges).

Mechanical properties, moisture resistance, strength and affordable price allow the yellow metal to be used in various fields without the fear that the material will collapse or rust.

Applications in watches and art

In the watch industry, brass has found particularly wide use due to its properties of pliability, ductility and low cost. Products made of yellow metal look presentable, and the clock mechanism works reliably for many years. The material does not rust, does not oxidize, and can withstand long stays in a humid environment without succumbing to corrosive processes.

In the decorative arts, brass is valued for its ability to create designer products with the effect of the presence of gold. The following ornamental two-component brass alloys are used to create jewelry:

green (zinc 40%);
golden tombac (zinc 25%);
classic yellow (zinc 33%).

Brass is an alloy with unique characteristics. Widely used in almost all structures used in difficult external conditions and aggressive environments. Jewelry made from brass looks luxurious, and with proper care, it does not lose its beauty for many years.

Coloring of metals can be done in two ways: chemical and mechanical. Chemical coloring of metals is based on changing the surface of metals by forming:

1) chemical compounds (sulfur oxides, compounds, etc.),

2) galvanic deposition. In both of these methods, the shiny surface of the metal is covered with a thin, foreign layer; in other words, the color of the top layer changes, but the properties of the metal do not change.

Chemical coloring of metals can also be done using electric current (metallochromia).

Mechanical painting of metals is carried out: 1) by applying paints and bronze powder, the adhesion of which is achieved by appropriate binders, then by smearing varnish paints; 2) by hammering in coloring powders; 3) by spraying atomized metal particles under strong pressure; 4) application of sheet metal, etc.; 5) enameling, i.e. coating with melting, colored, glass enamel; 6) blackening, i.e. fusing the appropriate black enamel powder into engraved or etched areas; 7) touching, i.e., driving differently colored wires or metal plates into etched recesses.

Chemical coloring of metals, in most cases, should be given preference over mechanical coloring, especially when it comes to works of art, since chemical coloring does not change the metal from which the object is made.

Before you begin chemical painting, it is absolutely necessary to clean the objects to be painted from all visible and invisible dirt, grease, layers of oxide, etc. adhering to them. First, the objects are cleaned, depending on the hardness of the metal, with steel wire or bristle brushes, Moreover, it is often necessary to resort to the help of fine sand, lime or pumice. Objects thus mechanically cleaned of dirt are then degreased. To do this, it is necessary to attach them to metal wires, because after degreasing they can no longer be touched. (Small items can be held with wooden tweezers.) It is advisable to immerse small objects several times in any fat-dissolving substance, such as ether, gasoline, ethyl chloride, etc. Large metal objects are boiled for 15-30 minutes in a diluted solution of caustic soda (1 caustic soda to 10 water), and then rinsed in several waters. Items made of zinc and tin, which can deteriorate in strong lye, are boiled in a 10% aqueous solution of soda or potash. Since under the influence of air these objects are covered with a layer of oxide, they are immersed for neutralization in a 10% solution of some acid. Due to the gases that develop during this process, this work must be done in a well-ventilated area. Then the items are rinsed in several waters and dried. If metal objects prepared in this way cannot be immediately lowered into the dye bath, then they are placed in a solution of 5 g of cream of tartar per 1 liter. water.

In order to achieve a quick and even coating in the dye bath, it is recommended to immediately immerse the items in a bath of equal parts denatured alcohol and water. Objects to be degreased and to be galvanized are placed, as a cathode, in a bath containing a sufficient amount of caustic soda or potash. To eliminate the oxidizing effect of oxygen released at the anode, a small amount of potassium cyanide is added. The latter must be handled with great care, as it is a very strong poison. Complete degreasing and complete cleaning of metal objects, as preparation for galvanic treatment, is achieved by adding a solution of hydrogen peroxide or substances that, when combined with water, form peroxide, to a solution of caustic alkalis. As a result, a strong separation of oxygen occurs on the metal surface, which, on the one hand, mechanically, tears off all particles of fat and dirt and this gives access to a solution of caustic alkalis to the metal surface itself, and, on the other hand, with its oxidizing effect, transforms some contaminants into soluble acids in alkalis.

If you want to paint an object only partially or in several places, then the parts that should remain unpainted are coated with asphalt varnish, after which the object is lowered into the dye bath. After painting, the varnish is removed with turpentine and, if necessary, the already painted areas are coated with varnish in order to paint the unpainted areas a different color in a new dye bath. This way you can make beautiful, complex designs. Metal objects cleaned in the manner described above are lowered, without touching them with your fingers, into the appropriate dye bath, and after that they are thoroughly rinsed so that no traces of dye liquid remain on them, which could cause stains. Then, in most cases, the items are wiped dry with clean sawdust or, if necessary, dried in a dryer at 90-100°. When painting, you need to keep in mind the fact that paints after drying always seem darker than on wet objects.

1. Gold coloring. Coloring of gold items. Grind 115 g of table salt and 230 g of saltpeter into a fine powder, pour over 170 cm3 of steaming hydrochloric acid and boil until chlorine is formed. Gold objects to be painted, which still show the color of the alloy from which they are composed, are suspended on platinum wire and immersed for 2-3 minutes in boiling gold paint. They are then rinsed with boiling water and, when the desired color is achieved, they are left to lie in the water until further processing. Thanks to the chlorine developed in the bath, chlorides of copper, silver and gold are formed. The latter, due to the copper content in the alloy, decomposes, and pure gold is deposited in a more or less thick layer. Then the items are once again immersed in boiling water and quickly dried.

2. Silver coloring. a) Coloring silver in brown gray-black and black. In a solution of 20 g of copper sulfate and 10 g of saltpeter in 20 g of ammonia, silver acquires a brown tone. b) Silver and silver alloys are painted black using an aqueous solution of bromine.

3. Copper coloring. a) Colored copper. Dissolve 130 g of sodium sulfate (hyposulfite), 0.5 g of sodium arsenic acid in 1 liter. water, on the one hand, and 10 g of crystals. Yari verdigris and 25 g of copper sulfate also in 1 liter. water, on the other hand. Mix equal parts of both solutions, in the amount required for the work ahead, and heat the mixture to 76-80°. If copper objects are immersed in this hot solution, they will be painted in the colors indicated below, with one color changing to the next after a few seconds, so you need to often remove the object from the bath to monitor the coloring process. In order of rotation, the following colors are obtained: orange, terracotta, light red, crimson, rainbow. On brass, this method produces the following colors: golden yellow, lemon yellow, orange, terracotta, olive green.

b) Coloring copper brown.

I) According to Groschuf, boiling copper in a solution of 12 g of copper sulfate in 100 cm3 of water after 10 minutes acquires a matte violet-gray color. This mixed color consists of a layer of brown cuprous oxide on which there is a coating of whitish-green base copper vinegar. Since there is very little of the latter, it can easily be made invisible by covering a painted and dried copper object with tsapon varnish or wiping it with warm linseed oil, Vaseline, wax, etc.

II) Dissolve 5 crystalline copper acetate, 7 ammonia and 3 diluted acetic acid in 85 distilled water. A copper object, brightly cleaned with glass sandpaper, is strongly heated under coals, lubricated with the above solution and, finally, wiped with a solution of 1 wax in 4 turpentine oil.

c) Yellow mordant for copper and copper alloys. First, objects are immersed in the so-called. preliminary mordant: in a mixture of 200 nitric acid, 36° according to B. with 1-2 table salt or 10% hydrochloric acid solution, with the addition, if necessary, of 1-2 soot. The yellow mordant itself consists of 75 nitric acid 40°B., into which 100 sulfuric acid 66°B. is slowly poured with constant stirring. Since this develops strong heat, the mixture is left alone until cooled. When used, then add approximately 5 g of table salt per 1 kg of mixture (to enhance the effect, also a little soot); Well-dried objects are quickly immersed in the mordant, shaking the bath for a few seconds, and then rinsed in several waters. Stains resulting from too long action of the yellow mordant can be removed by immersing objects in a solution of zinc chloride, lightly heating until dry and rinsing in water (according to Buchner).

4. Coloring brass, a) Brown. To paint the surface of copper things a beautiful and durable reddish-brown color, the following composition can be used: 4 copper acetate (jari verdigris), 4 crocuses and 1 horn trimmings. Crush well and mix with enough vinegar to form a paste.

Having coated the surface of the item with this composition and allowed it to dry, the item is heated until the composition turns black; After that, it is lubricated and polished - a beautiful reddish-brown color is obtained.

If you want the color to be darker - chestnut, then add 1 copper sulfate (in powder) to the above mixture; for a lighter, yellowish (bronze-like) color, instead of copper sulfate, add 0.5 - 1 borax. More or less artistic copper products (figurines, medals, etc.) are best painted with one of the following compositions:

I) Boil 32 copper acetate (verdienne) in powder, 30.75 crushed ammonia and 1 strong vinegar with 20 water. After boiling, let it settle and carefully drain the clear solution from the sediment, into which you immerse the items for 15 minutes. II) 5 copper acetate (crystalline), 7 ammonia, 3 acetic acid and 85 water. Immerse a copper item heated strongly over a charcoal fire into the solution; when it becomes colored, take it out, wash it, dry it and rub it with a solution of 1 wax in 4 turpentine. III) Boil 2 ammonia, 1 table salt, 1 saltpeter, 1 strong ammonia with 96 strong vinegar and immerse things in the boiling solution, keeping them there until they are properly colored there. Having taken it out, rinse first in a hot solution of ammonia in water, and then in boiling water.

If it is inconvenient to immerse things in solutions, then they can be lubricated with a sponge moistened with these solutions; but you need to lubricate evenly, and most importantly quickly; otherwise the coloring may appear patchy.

You can also lubricate things with liquid gruel prepared from 2 copper acetate, 2 cinnabar and 5 ammonia with the required amount of vinegar. Lubricated items are heated, washed and dried; lubricate again, heat up, etc., and so on several times until the coloring takes on the desired shade.

To dye things made of real bronze (i.e., an alloy of copper and tin) brown, it is better to use one of the following solutions:

I) 4 ammonia, 1 potassium oxalate and 200 vinegar. Things are lubricated with this composition, allowed to dry, lubricated again and allowed to dry, etc., repeating the operation until things acquire the desired color. The rather sharp metallic gloss remaining on things after this will soon disappear, and they will receive that pleasant soft brownish color, which, under ordinary conditions, forms on bronze only after several years (patina).

II) 1 crystalline copper acetate, 2 ammonia and 200 water. After smearing the surface of the item with this composition, dry it over the fire until the green color begins to disappear. Dilute the above composition with another 340 degrees of water and lubricate the item with this diluted solution another 10-20 times, each time drying it over the fire. This diluted composition can be prepared separately: 1 copper acetate, 2 ammonia and 600 water. This is even necessary if you want to operate on many things sequentially. After the first smears, the color has an olive-green color, but then it gradually takes on a more and more pleasant brown tint, which does not disappear even from very strong heating of things.

b) In green colors. The surface of copper, brass or bronze products can be painted green in various ways:

I) The surface of things, using a sponge, is first lubricated with a very diluted solution of copper nitrate with the addition of a small amount of table salt. Then, when the thing dries, it is lubricated in exactly the same way with a solution of 1 potassium oxalate and 5 ammonia in 94 weak vinegar. Let it dry again and again lubricate with the first solution; then, after drying, again with a second solution, etc. alternately until the coloring acquires the proper strength. Before lubricating, a sponge soaked in the solution should be squeezed out firmly so that it is damp, but not wet. After painting is completed, the surface of the item is thoroughly rubbed with hard hair brushes, especially in the recesses and crevices. After 8 - 14 days of work, a brownish-greenish color is obtained.

II) Things are rubbed in several stages with cloth soaked in crude oleic acid (a product obtained at stearin factories) and, before rubbing, strongly wrung out. On the surface of things, a dark green layer of copper oleic acid is first formed, which, under the influence of oxygen and air moisture, gradually turns into lighter green copper carbonate. The process is significantly accelerated if oleic acid is first infused on copper shavings for quite a long time, and after each lubrication with such acid, after the lubricant has dried, the items are lightly sprayed (no more than a few drops at a time) with an aqueous solution of ammonium carbonate.

c) Purple. Small brass items, for example, buttons, clasps, buckles, etc., can be painted purple by smearing a very heated item with a piece of cotton wool soaked in antimony oil. Antimony oil is impure antimony trichloride, which is available ready-made in pharmaceutical warehouses.

d) In golden colors.

I) Small brass items, such as buttons, clasps, buckles, etc., can be painted golden yellow by immersing them on copper wire in a neutral solution of copper acetate. The solution should be completely neutral, that is, it should not change the color of either red or blue litmus paper. Its neutralization, if necessary, is carried out with acetic acid.

II) Take 4 caustic soda, 4 milk sugar and 200 water and boil for 15 minutes, gradually adding 4 concentrates. sol. copper sulfate. The finished mixture is cooled and then brass items, previously cleaned of grease stains, are placed in it. After a short bath, the brass takes on a beautiful golden yellow hue.

III) Small brass items, for example, buttons, clasps, buckles, etc. can be painted golden-red by rubbing a mixture of 4 washed chalk (powdered) and 1 gold leaf, moistened with water to a paste consistency. Gold leaf is nothing more than sulphide (disulfide) of tin; it is similar in color to real gold and, like the latter, does not change from atmospheric influences.

IV) To give the copper a golden-red (orange) color, immerse it after thorough cleaning for a few seconds in a crystal solution. Yari verdigris.

V) Dissolve 15 g of sodium sulphate in 30 g of water, add 10 g of antimony chloride solution, heat to a boil, filter and rinse the resulting reddish precipitate in the filter several times and dilute it in 2-3 liters. hot water. While heating, add as much strong caustic soda solution until the precipitate dissolves. Immerse brass items in hot liquid and leave in it until they are painted the desired color.

e) In silver colors. I) Dissolve 40 g of tartar and 14 g of tartar emetic in 1 liter in a well-glazed vessel. hot water, then add 50 g of hydrochloric acid, 125 g of granular or even better powdered tin and 30 g of powdered antimony, heat the liquid to a boil and immerse the objects to be processed. After boiling for half an hour, they are covered with a beautiful hard and durable layer. II) 20 g of tartar emetic, hydrochloric acid until dissolved, water - 0.33 of the total volume.

5. Bronze painting.

a) Wipe the well-cleaned metal with a soft brush or rag with a solution of 22 g of ammonia and 6 g of potassium oxalate per 1 liter. vinegar until the area is dry and continue until the desired color is achieved.

b) To remove shine from new medals, statues, etc., bronze items, they are lubricated with a thick paste of 5 graphite, 15 well-worked bloodstone (red iron ore) and the required amount of pure wine alcohol. After 24 hours. remove dry powder.

c) 2 ammonia, 1 table salt and nitrate each are dissolved by heating in 96 vinegar, lubricate the objects with a hot solution and, after drying, clean with a brush.

6. Iron coloring.

a) As with zinc, the best method is indirect painting, i.e. the formation of a layer of copper and subsequent painting of the latter. For layering strength, it is recommended to use galvanic copper plating, mainly in an alkali-copper bath, which layer can be easily and firmly gilded, silvered or coated with brass.

b) If you cover an iron surface with a mixture of 3 sodium polysulfide and 1 lead acetate salt in dissolved form and heat it immediately, it will be covered with a layer of lead sulphide, through which the iron surface will shine through in different colors.

c) Brown. Typically, antimony oil mixed with olive or other vegetable oil is used for this. Using a cloth, rub this mixture onto the surface of an iron or steel item. When, a day after the first rubbing, the surface becomes covered with rust, it is rubbed with the same composition a second time, then a third, etc. This is continued until the desired color is obtained - from light to dark brown, depending on the number rubbing. This coloring is caused by the deposition of iron oxide and metallic antimony on the surface of things.

The coloring of iron in a metallic shiny dark brown color can be obtained if the iron, previously heated to a boil, is immersed for a moment in a 10% aqueous solution of red chrome salt (potassium dichromate), dried in air and then held for 1-2 minutes over hot wood coals. The operation is repeated 2-3 times until the desired shade is obtained. When finished, rinse, dry and wipe with a cloth lightly moistened with linseed oil. But for success, the iron must be heated to a temperature of 100°C (or very close). If the heating was not sufficient, then the coloring occurs poorly, and the water in which the iron is washed at the end of the operation turns yellow; if, on the contrary, the iron was heated too much, then the color of the paint will not be shiny brown, but matte black.

d) Blue. Dissolve, on the one hand, 140 g of sodium sulfate (hyposulfite) in 1 liter. water, on the other hand, 35 g of lead acetate in 1 liter. water, mix both solutions, put objects in there and slowly heat them to a boil, which makes the objects turn blue. Then they are taken out of the bath, dried and left for several hours in a warm place.

d) Black. I) According to Buchner, a strong, black color is achieved if the subject is lubricated with sulfuric linseed oil, then allowed to dry in moderate heat (for example, over coals) and then heated strongly, however, with caution so that the sulfuric linseed oil only chars, but does not ignite flame. It is best to heat it in a muffle.

II) Dissolve 18 zinc powder in a mixture of 57 phosphoric acid and 57 water; dilute 65 of this solution in 10,000 water, heat this mixture to a boil and immerse the iron objects to be blackened for 0.5-3 hours. Then the blackened objects are thoroughly washed in water.

III) Cast iron objects are thoroughly cleaned, matted with a thin stream of sand and lowered for 10 seconds. into a copper bath of the following composition: 10 g of copper sulfate, 15 g of tin chloride, 20 g of hydrochloric acid, 1 l. water.

Copper sulfate is dissolved separately, as well as stannous chloride, and both solutions are mixed. Then the object is washed well in hot water and painted black by immersion in a solution of sulfuric liver (6 g of sulfuric liver, 20 g of ammonia and 1 liter of water); After blackening, the object is again washed in hot water and dried in sawdust. For final finishing, cast iron is coated with asphalt varnish, to which a little soot, umber or some suitable paint is added.

7. Nickel painting. a) In gray color. Nickel can be colored gray by immersing the object in a solution of precipitated sulfur in ammonium sulphide. Nickel sulphide is formed and after several hours the color ranges from gray to black. b) Colored nickel painting. The “Color coloring of copper” recipe can also be applied to nickel, and in this case the result is first yellow, then blue, and finally, a rainbow color.

8. Zinc coloring. a) In different colors. Wipe the metal with gasoline to degrease it, and then immerse it in a bath of 6 g of nickel salt, 6 g of ammonium chloride and 100 g of water and leave in it for 2-3 minutes. Objects first take on a purple and then a brown color. b) Brown. Repeated application of 4 copper acetate (jari acetate) to 11 vinegar produces a brown coloration of the zinc.

If zinc products are first lubricated with a solution of 1 copper and 1 iron sulfate in 20 water, and then, after drying, with a solution of 4 copper acetate in 11 vinegar and, at the end of the operation, polished with crocus, then the surface of the things takes on a very beautiful dark bronze color.

By lubricating zinc items several times with a weak aqueous solution of copper chloride or copper dichloride and then heating and rubbing them with a brush, the darker the color is obtained, the stronger the solution and the more times the lubrication is repeated. After sufficient repeated lubrication, the brown color turns to almost black.

If you add as much ammonia to a solution of copper chloride as is necessary for the precipitate that forms initially to dissolve again, then from repeated lubrication with such a liquid, things will turn copper-red. By adding a little vinegar to the said liquid, the color is given a yellow-brown tint.

A very beautiful brown color is produced by a solution of 15 chrome alum and 15 sodium sulfate (hyposulfite) in 500 boiling water; after cooling, 25 sulfuric acid is added to the solution. Then they filter it and, having heated it to a boil, immerse things in it and keep it in it, stirring, until they take on the desired shade.

Small zinc items can be painted brown-bronze by immersing them in a weak solution of copper sulfate acidified with vinegar. After immersion, the items are dried in air and the immersion is repeated (drying each time) until the coloring takes on the desired shade. The weaker the copper solution and the more often the immersion has to be repeated, the more beautiful and durable it is.

c) Green. Dissolve 50 sodium sulfate (hyposulfite) in 500 boiling water, add 25 sulfuric acid, filter (to separate precipitated sulfur) and immerse zinc items in the solution, which very quickly become covered with a light green coating. If you keep things in the solution for a longer time, the light green color turns into dark green. But for this type of painting, it is best to first coat zinc items with copper and then treat them as if they were copper.

d) Marbled. In an enameled cauldron, dissolve 50 g of copper sulfate, 50 g of nickel salt (double salt of nickel and sulfur-ammonium salts) and 50 g of berthollet salt in 3 kg of distilled water. Zinc items are degreased by washing in a weak soda solution, dried, and then dipped into a solution heated to 60°. Depending on the duration of the bath, a layer of color ranging from yellow to black is formed, which is very durable. The items are then rinsed with water, dried in heated sawdust, wiped with oil and, if desired, coated with another colorless varnish.

9. Tin coloring. The easiest way to color tin is to electroplate the item with copper or brass and then paint it like copper.

10. Aluminum painting. The easiest way to paint aluminum is to coat it (via dip) with a layer of copper or silver and paint the resulting metal layer accordingly.

11. Finishing of painted metals. The surface of chemically painted metal objects usually has a matte appearance after painting, and the paint tone is cold. Therefore, it is very important to subject the painted object to subsequent treatment, which also has the advantage of protecting the painted surface from the action of air. By friction the metallic luster is restored again. Depending on the type of coloring, they rub with cloth, soft or hard brushes, if necessary, even with wire brushes, and resort to pumice or lime powder. High spots on metal objects should appear lighter than low spots, which can be achieved by polishing with pumice or crocus.

If you want a metal object to remain matte, then it is best to slightly warm it up and coat it with celluloid varnish using a brush. Objects coated with celluloid varnish become hard, non-sticky and very durable after drying. Ready-made celluloid, colorless tsapon lacquer is available for sale. Tsaponlak has the advantage that it does not leave streaks after drying. Shiny metal objects can also be coated with a layer of this varnish without losing their original shine.

Treatment with wax or ceresin gives a metal object a warm tone without much shine. Objects are treated with brushes rubbed with wax or ceresin.

Metal objects acquire a strong shine if they are coated with a thin layer of varnish. In most cases, colorless varnish is used, but you can also achieve a great effect on a painted object with colored varnishes.

12. Wax composition. When making a wax composition used for partial coloring of metals, all the individual parts that form the composition are first ground into the finest powder and sifted through a sieve, and the remainder is pounded again. After this, melt the wax in a clean pot, without heating it too much, and add, with constant stirring, the individual components one after another. Then the mass is immediately poured into a cooled vessel moistened with water, continuing to stir all the time, allowed to cool and then cut into pieces.

a) 8 white wax, 2 verdigris and copper sulfate each, 0.25 borax. b) 12 white wax, 3 Armenian boluses, 1.5 verdigris, 2 ferrous sulfate, 0.5 burnt sienna, 0.25 borax. c) 12 white wax, 0.5 yari-copper, 3 copper ashgar, 0.25 borax. d) 18 yellow wax, 6 verdigris, 6 zinc sulfate, 8.5 red clay iron ore (sanguine), 4 copper ash, 3 iron sulfate, 0.5 crocus, 0.25 borax. e) dissolve 1 yellow wax in 15 benzene. e) Boil 1 sound soap, 3 Japanese wax and 20 water together and stir frequently while cooling. g) Dissolve 1 wax in 2 hot turpentines.

Note: Solution “d” is applied with a brush, solutions “e” and “g” are applied with a cloth or brush and wiped dry with a brush.

Author: G. Brodersen

Brass Photos

Process Features

In industry, non-ferrous metals in their pure form are practically not used, but rather alloys are used, which makes it possible to achieve the required properties. During the production of non-ferrous metals, their chemical, physical and mechanical properties are modified, which is very important for the manufacture of both household and industrial items.

A special feature of non-ferrous metals is their ease of processing. Almost all of them are ground, forged, stamped, pressed, cut, welded or soldered.

During production from these substances it is possible to obtain not only finished products, but also a variety of semi-finished products:

rods;
wire;
powder;
foil.

Production of non-ferrous metal wire

Tungsten

Silver-gray tungsten is not only one of the hardest metals, it also leads in refractoriness. It can only be melted at a temperature of 3422 °C. Due to this property, it is used to create incandescent elements. Alloys made from this element have high strength and are often used for military purposes. Tungsten is also used to make surgical instruments. It is also used to make containers in which radioactive materials are stored.

Tungsten

Chromium

Chromium is one of the hardest metals. It was discovered in Russia in 1763 in a deposit in the Northern Urals. It has a bluish-white color, although there are cases where it is considered a black metal. Chrome cannot be called a rare metal. The following countries are rich in its deposits:

Kazakhstan;
Russia;
Madagascar;
Zimbabwe.

Chromium

There are chromium deposits in other countries as well. This metal is widely used in various branches of metallurgy, science, mechanical engineering and others.

Uranus

One of the hardest metals is uranium. It was discovered in 1840 by the chemist Peligo. D.I. Mendeleev made a great contribution to the study of the properties of this metal. The radioactive properties of uranium were discovered by the scientist A. A. Becquerel in 1896. Then a chemist from France called the detected metal radiation Becquerel rays. Uranium is often found in nature. The countries with the largest deposits of uranium ore are Australia, Kazakhstan and Russia.

Uranus