Coin metals: nickel and aluminum. Application of aluminum-nickel alloy Aluminum-nickel alloy

1 Abstract 2

2 Introduction 3

3 Characteristics of part 4

4 Choice of nickel plating method 5

4.2 Electrolytic method 5

4.2 Chemical method 5

5 Requirements for the coating and the choice of its thickness 6

6 Choice of implementation of the technological process 7

7 Theory of the chemical nickel plating process 8

8 Choice of solution 10

9 Selection of basic technical operations 12

9.1 Chemical degreasing 12

9.2 Electrochemical degreasing 13

9.3 Etching 13

9.4 Lightening 14

9.6 Chemical nickel plating 14

9.7 Flushing 14

10 Process flow diagram 16

11 Compositions of solutions and modes of their operation 17

12.1 Calculation of the dimensions of suspensions and chemical bath

nickel plating 19

12.2 Calculation of funds operating time of equipment 21

12.3 Annual production of one chemical bath

nickel plating 22

12.4 Chemical consumption 22

12.5 Correcting solutions 24

12.6 Water consumption 28

12.7 Water consumption for flushing 30

13 References 33

2 Introduction

The use of aluminum alloys for the manufacture of machine parts increases every year, which is due to a number of specific properties of aluminum (lightness, pliability to stamping, corrosion resistance (in air, aluminum is instantly covered with a strong film of Al 2 O 3, which prevents its further oxidation), high thermal conductivity, non-toxicity But aluminum has a significant drawback - low hardness (100-150 MPa), as a result of which the surface of parts working for friction is quickly triggered.Therefore, it is of great practical importance to strengthen the surface of parts made of aluminum alloys by applying a harder layer of another metal. In this respect, nickel plating, which has high hardness and adhesion to the base, especially after heat treatment, is of great practical interest.

Nickel coatings are used in various industries both as an underlayer and independently for protective, decorative and special purposes. They are characterized by hardness, significant corrosion resistance and good reflectivity (58 - 62%), electrical resistivity of 8.3-10 -2 Ohm · m.

Nickel coatings are used in industry for protective, decorative and decorative finishing of products and parts of machines, apparatus, devices; for corrosion protection at elevated temperatures and in special environments (alkalis, some acids), as an intermediate sublayer for applying other coatings to steel in order to ensure strong adhesion of coatings to the base, to increase the wear resistance of rubbing surfaces.

Currently, two methods of applying nickel plating are used: electrochemical and chemical. Only with the help of chemical nickel plating can complex-shaped parts be coated. By introducing inorganic additives containing phosphorus and boron, the hardness of the resulting coating can be controlled, which is important for parts made of aluminum alloys. It should be borne in mind that the coatings obtained by chemical nickel plating have high corrosion resistance.

3 Characteristics of the part

As a part for coating, the body of the electronic device, made by milling and from an aluminum alloy D16

The part is coated both from the outside and from the outside, the presence of various holes for the output of wires, bolted connections is characteristic.

This housing with an electronic device is subsequently sealed using a bolted connection or low-temperature soldering. To ensure reliable operation of the device, the coating applied to the housing must provide corrosion resistance, wear resistance, optimal hardness and be uniform in thickness.

Usually, cases made of aluminum alloys are subjected to a nickel plating operation, followed by the application of other functional coatings, for example, tin, bismuth, and silver coatings.

Detail dimensions:

l = 5.4cm 2, h = 8.8cm 2, b = 1.3cm 2

Since the part is covered both from the outside and from the inside, the coverage area of one part will be equal to:

S cover = 168 cm 2

4 Choice of nickel plating method

There are two possible ways to apply nickel plating:

4.1 Electrolytic method

The electrolytic method is the application of nickel coatings to the surface of an electrolyte product under the action of an electric current. The advantage of this method is that the thickness of the coating is clearly controlled, the minimum consumption of the coating metal is. In addition, by choosing the type of electrolyte and the deposition mode, it is possible to obtain deposits of the desired structure, appearance, and with different mechanical properties. The disadvantage of electrolytic nickel plating is the uneven deposition of nickel when applied to a relief surface, as well as the impossibility of covering narrow and deep holes and cavities.

4.2 Chemical method

In the chemical method, the article to be coated is placed in an aqueous solution containing a dissolved metal salt and a reducing agent. A layer of metal is deposited on the surface of the product.

The plating deposited in the process of chemical nickel plating is not pure nickel, as in electroplating nickel plating, but consists of an alloy of nickel with phosphorus. The coating with this alloy has nothing to do with the pure nickel coating in terms of both physical-mechanical and chemical-corrosive properties.

The coating can be applied to products of complex configuration with a high degree of uniformity. It can be applied to the internal cavities and channels of the product, which is practically impossible to implement with electroplating.

The wide range of applications of chemically deposited nickel-phosphorus coating is explained by an impressive set of its useful properties: hardness from 6,000 to 10,000 MPa, high corrosion resistance, antifriction (low wear during dry friction), the ability to screen high-frequency electromagnetic radiation, low transient resistance at electrical contacts, good solderability.

The mechanical properties of nickel plating do not depend on the thickness: for example, coatings with a thickness of 1 μm and 100 μm have the same specific wear resistance.

In this case, it is more expedient to use chemical nickel plating. This is due to the fact that the part has a complex configuration (the presence of holes, depressions, cavities), and also requires coating, both from the outside and from the inside.

5 Requirements for the coating and the choice of its thickness

The thickness of the coating is set depending on the operating conditions, the purpose of the coating according to the normative and technical documentation, as well as the method of coating.

Since it is necessary to apply a functional coating to our part, the coatings must be uniform in thickness, and also provide corrosion resistance, wear resistance and hardness of the base metal under operating conditions.

According to GOST 9.303-84, the minimum coating thickness should be 9 microns. The maximum permissible coating thickness is 15 µm. The average nickel thickness obtained in the nickel plating bath is 15 microns.

6 Choice of implementation of the technological process

There are three ways to carry out the technological process of chemical nickel plating, which differ depending on the type of reagent selected as a reducing agent.

1) hypophosphite method, characterized by the joint release of phosphorus into the nickel coating;

2) borohydride method, in which boron is released, which is part of the coating;

3) hydrazine method, in which nickel is deposited with the least amount of impurities.

So far, only the hypophosphite method has received industrial application. This is due to the fact that the borohydride coating method is characterized by a highly alkaline medium (pH> 13), which will lead to the dissolution of aluminum.

Despite the fact that the hydrazine method makes it possible to obtain a high-quality nickel coating, its use is practically not widespread, due to the low deposition rate of nickel, the main component (hydrazine) is practically absent from the market, this method is very demanding in observing safety precautions, because if the operating conditions are violated, detonation is possible.

Chemical deposition of nickel on aluminum alloys is expediently carried out using a solution with sodium hypophosphite. The deposited coating has a semi-shiny metallic appearance, amorphous structure and is a nickel-phosphorus alloy.

7 Theory of the chemical nickel plating process

The mechanism of the reduction of nickel ions using hypophosphite is electrochemical in nature, while the anodic stage of oxidation of the reducing agent (5.1) and the cathodic stage of the reduction of nickel (5.6) and hydrogen (5.3) proceed simultaneously (conjugately) on the surface of the catalyst-base.

The anodic stage of oxidation of hypophosphite - the reaction of interaction of sodium hypophosphite with water - is represented as the addition of the ОН¯ ion from the water molecule to the site of bond cleavage

P - H in sodium hypophosphite molecule. This reaction, which is facilitated by the catalytic action of the nickel surface, can be expressed by the following equation:

Н 2 О ↔ Н + + ОН¯, (5.1)

Н 2 РО 2 ¯ + ОН¯ → Н 2 РО 3 ¯ + Н + е. (5.2)

An electron freed from the hypophosphite anion through a metal surface can be transferred to a hydrogen ion and convert it into an atomic one:

H + + e → H. (5.3)

Two hydrogen atoms, one of which was formed from the P - H bond of the hypophosphite anion, and the other from water, joining together form molecular hydrogen.

Permissible metal contacts according to GOST 9.005-72

Any electrician knows that copper and aluminum wires should not be twisted together. A copper ground bar or brass board stand does not work well with galvanized screws purchased from your local hardware store — corrosion can destroy the electrical contact. A bare aluminum part in general can gradually turn to dust if even low voltage is applied to it.

In Soviet GOSTs, almost everything was written about permissible metal contacts, but now it can be very inconvenient to look for information about compounds in old documents. Habrayuser @teleghost collected all the data in one table.

The letter "A" means "limited permissible in atmospheric conditions." The definition of this concept from GOST under the spoiler.

These contacts can be used in products, the design features and operating conditions of which allow periodically renewing the protection of contact surfaces by applying working or conservation lubricants, paint and varnish coatings, or subject to the admissibility of corrosion damage to the contacting materials for the designated service life of the product.

A few words about metals.

Cink Steel- the main workhorse of the national economy. In the form of various hardware, "galvanized" is found in building materials stores much more often than, for example, stainless steel. Factory PC cases, technological boxes and equipment cabinets are most often made of galvanized cold-rolled steel with a thickness of about 1 mm.

Stainless steel- the queen of steels: strong, ductile, corrosion resistant, electrically conductive, cool looking. Too tight to cut and bend at home on an industrial scale. Chromium and chromium-nickel stainless steel are electrically poorly compatible with zinc and "bare" steel, but they give reliable contact with copper without the help of tin. Aluminum and nitrided, oxidized and phosphated low alloy steels have limited compatibility under standard atmospheric conditions. A2 grade stainless steel does not "magnet", but there are stainless steels with magnetic properties. Magnetic properties do not affect the corrosion resistance of stainless steel.

Aluminum and its alloys are anodized (with a protective layer) and conventional (non-anodized). Aluminum is easy to handle at home, but corrosion must be kept in mind. Do not use bare aluminum as a conductor, even with low voltage, or the current will slowly turn the part to dust. The aluminum and duralumin parts processed in the workshop show full equipotentiality (the currents induced by the fields seem to be according to figs, it is also possible to ground it). Aluminum is compatible with zinc plating, but a tin gasket is required for contact with copper, "bare" or nickel-plated steel. Limited contact of aluminum with stainless steel in atmospheric conditions. For simplicity, it can be assumed that, in contact with other metals and coatings, aluminum will corrode on its own, without the aid of external electricity.

Copper soft and rather unappetizingly oxidized in air, therefore copper products are enclosed in an airtight sheath or varnished. The brass plaques of soldier's belts and stands for electronic printed circuit boards resist oxidation better and look more appetizing than green copper, especially if they are periodically polished (I'm talking about the plaques, of course). At the same time, neither copper, nor its alloy with zinc (brass) "are friends" with pure zinc and its coatings. But copper is combined with chrome, nickel and stainless steel. And if you are holding any terminal in your hands, then it is probably made of tinned (tinned) copper.

Tin relatively resistant to corrosion (in room conditions) and electrically compatible with almost everything except cast iron, low alloy and carbon steels and magnesium. It is not necessary to solder with tin and beryllium, be careful when assembling a home nuclear reactor. Tin is used to obtain a valid electrical contact from an unacceptable contact, i.e. as a "gasket". Tinned copper terminals are a great example.

You should not use tin at low temperatures - since the last century, the so-called. "Tin plague" - polymorphic transformation of the so-called. "white tin" to "gray" (b-Sn → a-Sn), in which the metal crumbles into a gray powder. The reason for the destruction is a sharp increase in the specific volume of the metal (the density of b-Sn is higher than that of a-Sn). The transition is facilitated by contact of tin with a-Sn particles and spreads like a "disease". The tin plague has the highest rate of spread at a temperature of -33 ° C; lead and many other impurities delay it. As a result of the destruction by the "plague" of tin-soldered vessels with liquid fuel, R. Scott's expedition to the South Pole perished in 1912.

Nickel covered with shiny "computer" cogs. This coating is compatible with copper and bronze, brass, tin, chrome and stainless steel. Nickel is incompatible with zinc and aluminum (contact with stainless steel is better for aluminum, see below).

Features of the corrosiveness of non-metals. Appendix 3b to GOST 9.005-72:

The corrosiveness of organic materials is determined by the activity of the emitted aging products.
- The corrosive aggressiveness of phenolic plastics, aminoplasts, foams, formaldehyde adhesives is determined by the release of formaldehyde, the possibility of its oxidation to formic acid and urotropin, which can be a source of ammonia.
- The corrosiveness of wood materials is determined by the release of acetic and formic acid solutions.
- The corrosiveness of epoxy materials is determined by the presence of free chlorine and hydrogen chloride, carboxylic and dicarboxylic acids.
- Corrosion aggressiveness of rubber products is determined by the content of sulfur and its compounds, hydrogen compounds with halides, organic compounds with oxidizing properties.
Polymer materials obtained by the condensation reaction (epoxy, polyester, etc.) are most corrosive during the curing period. It is not recommended to carry out the curing process in closed volumes of the structure.
Irradiation of a non-metal by ionizing radiation (ultraviolet, gamma radiation, etc.) can increase its corrosiveness.
The corrosive aggressiveness of a non-metal in direct contact with a metal is determined by its water and oxygen permeability. The values of water and oxygen permeability for a number of non-metals are given in Tables 4 and 5.

The first three were the main coin metals, although since ancient times there have been few attempts to use some other metals for making coins. In ancient Byzantium, in medieval China and Japan, iron coins were used. In the last years of the Roman Republic, in China IX-X centuries. There are coins made of lead, and on the islands of Sicily, Java, Borneo and Sumatra, coins are made of tin. In ancient Bactria, coins were made from an almost modern copper-nickel alloy containing 20% nickel; this composition corresponded to the natural ore deposits from which the metal was smelted.

At the end of the 19th century, a fourth, nickel, was added to the three main coin metals. This metal was discovered in 1751 by the Swedish mineralogist Axel Frederik Kronstedt (1722−1765). He explored a reddish brown ore. It resembles copper in color, and when medieval German miners were unable to smelt metal from this ore, they called it "kupfernickel", that is, "devil's copper" (from him. Kupfer- copper and Nickel- an evil mountain spirit, or gnome). By the way, once in Russian (for example, in Mendeleev's "Foundations of Chemistry") they wrote, according to the German template, "nickel". Canada is one of the leading nickel mining countries in the world. And in 1951, in honor of the 200th anniversary of the discovery of this important metal for the country, a nickel five-cent coin was issued in Canada. Rice. 1. Nickel nickel nickel (Canada) In the United States, nickel nickels are traditionally called nickels, although in reality they are minted from a copper-nickel alloy, in which there is only 25% nickel (Fig. 2). But already 15% of nickel completely mask the color of copper in the alloy, making it pure white. The first coins in the USA made of a copper-nickel alloy had a different denomination - three cents; they replaced the old three-cent silver coins and were minted from 1865 to 1889. It is interesting that on October 8, 1942, “nickels without nickel” appeared in circulation in the United States - they contained 56% copper, 9% manganese and ... 35% silver! The reason is simple: at the end of 1941, the United States entered World War II, and the military needed large quantities of nickel to make steel armor. Such coins were minted until 1945. How much nickel could be saved? In 1941 alone, 300,152,000 five-cent coins weighing 5 g each and a total mass of 1,500.76 tons were minted, of which pure nickel accounted for more than 375 tons. This made it possible to produce almost 10 thousand tons of Krupp armor!

Rice. 3. Three cents For the first time coins from a copper-nickel alloy began to be minted in Switzerland in 1850.

And from nickel - in the Austro-Hungarian Empire since 1892 (10 and 20 hellers). Coins of almost pure (99%) nickel were minted in 1923-1943 in Italy (two lira), and coins in denominations of one lira, 50, 25 and 20 chentesimo contained 97.5% nickel in different years. In the twentieth century, nickel coins were minted in many countries - Belgium, France, Switzerland, Germany, Hungary, Luxembourg, the Netherlands, etc.

Rice. 5. One lyre of 1922 In the Russian Empire, the famous physicist who discovered electroforming, Academician Boris Yakobi, spoke for the minting of a nickel coin. He represented Russia in an international commission to develop common units of measures, weights and coins. At his request, in 1871, trial samples of the proposed coins were minted at the Brussels Mint. However, the Ministry of Finance rejected this proposal, as well as the subsequent ones coming from England, France and Germany. At the beginning of the twentieth century, rich nickel ores were discovered in Russia, and a proposal to start minting nickel coins came in 1911, now from the St. Petersburg Mint. But the war that began soon buried this initiative too. Coins from a copper-nickel alloy began to be minted in the USSR only in 1931. The alloy composition changed with the redesign of Soviet coins in 1961. Thus, the analysis of the alloy of the 20-kopeck coin of 1978 showed that it contains 52.77% copper, 31.72% zinc, 11.40% nickel, 3.85% manganese and 0.26% iron.

Rice. 6. Trial nickel coins of 1871

Rice. 8. Twenty kopecks 1931 Very light, cheap and looks good aluminum coins, but only while they are new. Soft aluminum wears out quickly, corrodes easily, and coins become quite unsightly. Coins made of aluminum were minted (and in some places are still minted) in the GDR, Poland, Czechoslovakia, Albania, Hungary, Mongolia, Austria and a number of other countries.
Rice. 9. On the right is an uncirculated aluminum coin (Cuba, five centavos, 1971), on the left is a corroded aluminum coin (France, two francs, 1943) An amazing story happened to the Italian aluminum coins. (Strictly speaking, they were not minted from pure aluminum, but from an alloy italma- from "Italy", "aluminum" and "magnesium", but aluminum in this alloy is 96.2%, and magnesium - only 3.5%, and 0.3% manganese.) From this on the right in the post-war Italian Republic, coins were minted the smallest denominations: 1, 2, 5 and 10 lire. As mentioned in the first article about coins made of gold, silver and copper, the price of the metal in the coin once corresponded to the face value. The so-called damage to the coin is known, when the rulers maliciously reduced the purity of the precious metal. But history also knows exactly the opposite cases, when the value of the metal exceeded the face value of the coin. As a rule, this is due to inflation and the clumsiness of officials who do not stop minting coins in a timely manner, as they say, at a loss. In Italy, in the 1970s of the twentieth century, there was an acute shortage of a bargaining chip - the smallest denominations almost disappeared from circulation. It turned out that some firms bought these cheap coins, the metal of which was worth more than the face value, and used them for various purposes, for example, as a basis for buttons - it was cheaper than stamping mugs even from inexpensive aluminum. As a result, the Italian government took urgent measures to mass minting small coins. So, if in 1970 3.1 million five-pile coins were minted, then in 1972 - already 16.4 million, and in 1973 - 28.8 million! And although back in 1976 the lira corresponded to only $ 0.0012, that is, nothing could be bought for it, mass minting of small coins continued almost until the transition to the euro in 2002. As if in mockery, a cornucopia was depicted on the one lyre coin. For the sake of fairness, it should be said that the circulation of aluminum coins in the late XX - early XXI century, of course, was modest. So, in 2001, only 110 thousand five-pile coins were minted, but not for circulation, but for collectors - of improved quality.

Ilya Leenson,
Cand. chem. Sci., Associate Professor of the Higher Chemical College of the Russian Academy of Sciences

Alnwick (English Alnwick, ˈ listen [ˈænɨk]) - a small trading town (English Market town) in the North-East of England in the county of Northumberland.
Alloy Fe with Ni and Al
Hard magnetic alloy
Nickel-aluminum base alloy
Permanent Magnet Alloy
Permanent Magnet Alloy
Magnetic alloy
Alloy for manufacturing constant magnets
Iron alloy with nickel and aluminum
Magnetic alloy of iron, nickel, aluminum
(from aluminum and nickel) hard magnetic alloys Fe (base) with Ni (20-34%) and Al (11-18%), sometimes with additions of Cu, Co, Si, Ti

Yuval Avital (Jerusalem, 1977) is an Israeli musician, composer and guitarist.
Alloy with aluminum
Aviation aluminum alloy
Light alloy
High ductility aluminum alloy
Aircraft Aluminum Alloy
Light alloy for winged liners
Alloy, aircraft grade aluminum
Aviation aluminum

Melchior (German Melchior, distorted from the French Maillot-Chorier) is a single-phase copper alloy, mainly with nickel, sometimes with additions of iron and manganese, named after French inventors from Lyon Maillot and Chorier , who created their alloy in 1819. Typically, cupronickel contains 5-30% nickel, ≤0.8% iron and ≤1% manganese, although in some cases it differs from these proportions.
Jewelry alloy
Cookware alloy
Copper-Nickel Alloy
Nickel Copper Alloy
Silver-white copper-nickel alloy
Silver-plated metal alloy, better known as new silver
A heavy alloy based on copper and nickel, similar to silver and widely used in cutlery and tableware
Spoon and Fork Alloy
Stainless alloy

The first three were the main coin metals, although since ancient times there have been few attempts to use some other metals for making coins. In ancient Byzantium, in medieval China and Japan, iron coins were used. In the last years of the Roman Republic, in China in the 9th-10th centuries there are coins made of lead, and on the islands of Sicily, Java, Borneo and Sumatra - of tin. In ancient Bactria, coins were made from an almost modern copper-nickel alloy containing 20% nickel; this composition corresponded to the natural ore deposits from which the metal was smelted.

In the United States, nickels are traditionally called nickels, although in reality they are minted from a copper-nickel alloy, in which there is only 25% nickel (Fig. 2). But already 15% of nickel completely mask the color of copper in the alloy, making it pure white. The first coins in the USA made of a copper-nickel alloy had a different denomination - three cents; they replaced the old three-cent silver coins and were minted from 1865 to 1889. It is interesting that on October 8, 1942, “nickels without nickel” appeared in circulation in the United States - they contained 56% copper, 9% manganese and ... 35% silver! The reason is simple: at the end of 1941, the United States entered World War II, and the military needed large quantities of nickel to make steel armor. Such coins were minted until 1945. How much nickel could be saved? In 1941 alone, 300,152,000 five-cent coins weighing 5 g each and a total mass of 1,500.76 tons were minted, of which pure nickel accounted for more than 375 tons. This made it possible to produce almost 10 thousand tons of Krupp armor!

For the first time coins from a copper-nickel alloy began to be minted in Switzerland in 1850.

And from nickel - in the Austro-Hungarian Empire since 1892 (10 and 20 hellers). Coins of almost pure (99%) nickel were minted in 1923-1943 in Italy (two lira), and coins in denominations of one lira, 50, 25 and 20 cents e in winter they contained 97.5% nickel in different years. In the twentieth century, nickel coins were minted in many countries - Belgium, France, Switzerland, Germany, Hungary, Luxembourg, the Netherlands, etc.

In the Russian Empire, the famous physicist who discovered electroforming, academician Boris Yakobi, advocated the minting of nickel coins. He represented Russia in an international commission to develop common units of measures, weights and coins. At his request, in 1871, trial samples of the proposed coins were minted at the Brussels Mint. However, the Ministry of Finance rejected this proposal, as well as the subsequent ones coming from England, France and Germany. At the beginning of the twentieth century, rich nickel ores were discovered in Russia, and a proposal to start minting nickel coins came in 1911, now from the St. Petersburg Mint. But the war that began soon buried this initiative too. Coins from a copper-nickel alloy began to be minted in the USSR only in 1931. The alloy composition changed with the redesign of Soviet coins in 1961. Thus, the analysis of the alloy of the 20-kopeck coin of 1978 showed that it contains 52.77% copper, 31.72% zinc, 11.40% nickel, 3.85% manganese and 0.26% iron.

Aluminum coins are very light, cheap and look good, but only as long as they are new. Soft aluminum wears out quickly, corrodes easily, and coins become quite unsightly. Coins made of aluminum were minted (and in some places are still minted) in the GDR, Poland, Czechoslovakia, Albania, Hungary, Mongolia, Austria and a number of other countries.

An amazing story happened with Italian aluminum coins. (Strictly speaking, they were not minted from pure aluminum, but from an alloy italma- from "Italy", "aluminum" and "magnesium", but aluminum in this alloy is 96.2%, and magnesium - only 3.5%, and 0.3% manganese.) From this on the right in the post-war Italian Republic, coins were minted the smallest denominations: 1, 2, 5 and 10 lire. As mentioned in the first article about coins made of gold, silver and copper, the price of the metal in the coin once corresponded to the face value. The so-called damage to the coin is known, when the rulers maliciously reduced the purity of the precious metal. But history also knows exactly the opposite cases, when the value of the metal exceeded the face value of the coin. As a rule, this is due to inflation and the clumsiness of officials who do not stop minting coins in a timely manner, as they say, at a loss. In Italy, in the 1970s, there was an acute shortage of bargaining chips - the smallest denominations almost disappeared from circulation. It turned out that some firms bought these cheap coins, the metal of which was worth more than the face value, and used them for various purposes, for example, as a basis for buttons - it was cheaper than stamping mugs even from inexpensive aluminum. As a result, the Italian government took urgent measures to mass minting small coins. So, if in 1970 3.1 million five-pile coins were minted, then in 1972 - already 16.4 million, and in 1973 - 28.8 million! And although back in 1976 the lira corresponded to only $ 0.0012, that is, nothing could be bought for it, mass minting of small coins continued almost until the transition to the euro in 2002. As if in mockery, a cornucopia was depicted on the one lyre coin. To be fair, it should be said that the circulation of aluminum coins in the late XX - early XXI century, of course, was modest. So, in 2001, only 110 thousand five-pile coins were minted, but not for circulation, but for collectors - of improved quality.