Man has been using powders of various kinds of metals since ancient times. For example, crushed gold and silver were once used to decorate ceramics. Also, such materials were used in painting. Currently, copper powder is widely used in industry.
What is a
In most cases, such a powder is 99.5% copper. Also, its composition may include in a small amount various kinds of impurities of other metals. Most often, it is lead, tin and iron. In another way, such material is also called copper powder.
How is it made
Chemical enterprises of the non-ferrous metallurgy industry are manufacturing this product. The main methods for producing copper powder are two:
mechanical;
physical and chemical.
When using the first technology, a powder with practically unchanged chemical composition is obtained. The second method is considered somewhat more complicated. When applied, the starting material substantially changes the initial properties.
The mechanical method of obtaining
Copper in this case for the manufacture of powder can be used both solid and molten. This product itself is obtained by mechanical action on it. For solid material, this can be grinding, abrasion, grinding, crushing.
Molten copper is turned into powder by crushing its stream with gas or water. This method allows to obtain a sufficiently pure homogeneous product. In addition, using this technique, it is possible to produce a powder with a given number of particles of a certain size and shape.
Physicochemical method
Using this technology, the raw material undergoes deep physical and chemical transformations. Most often, this is a dissolution process followed by reduction, called cementation. Typically, using this technique, copper powder is precipitated using less valuable metals, such as iron.
In an autoclave production method, Cu is reduced from a solution of its salt with hydrogen. Such a reaction takes place at the enterprise at the same time at elevated temperatures and pressure.
Often, the hydroelectrometallurgical method is also used to produce copper powder. In this case, the product is obtained by electrolysis of aqueous sulfate solutions of copper using soluble anodes (under certain conditions). Perform this procedure in bunker-type bathtubs with lower powder discharge. The surfaces of such containers are lined with acid-resistant materials.
Main applications
Powder produced by modern industry is in most cases non-toxic, non-radioactive, non-explosive and not even fire hazard. Therefore, the scope of its application is quite wide. Most often, this non-ferrous metallurgy product is used in powder metallurgy.
Also, such material is widely used:
in the paint and varnish industry;
in the chemical industry;
in ordinary metallurgy;
in the coal industry;
in microelectronics;
in the automobile industry;
in the aviation industry;
in nanotechnology;
in instrumentation.
In the manufacture of all kinds of paints, copper powder is used as a pigment. In the metallurgical industry, it is used for spraying processes. Also, this material is used in the manufacture of carbon electrodes.
In the automotive industry, metal powder is used, for example, in the manufacture of tires, as well as anti-wear parts.
In powder metallurgy, this material is primarily used for the production of various kinds of sintered products. It can be, for example, all kinds of rings, bushings, etc.
Powder classification
Modern industry produces several grades of copper powder. At the moment, on sale you can find products of this type:
MA and PM are unstabilized.
PMS-K - stab stabilized.
PMS-A, PMS-11, PMS-1, PMS-B are conventional stabilized.
PMU - ultrafine copper powder.
PMR, PMVD - a highly dispersed product.
In the manufacture of powder from copper, like any other material, enterprises in Russia, of course, must comply with certain standards and norms.
GOST 4960 for electrolytic powders: impurities
The main producer of such products in our country at the moment is Uralelectromed JSC. Of course, electrolytic copper powders at this plant are also produced in strict compliance with the standards provided by state standards. GOST 4960 regulates the production of such products in Russia today. This document, among other things, regulates the amount of impurities in the material of a particular brand.
For example, a powder of copper PMS-V should contain:
iron - not more than 0.018%;
arsenic - 0.003%;
lead - 0.05%;
oxygen - 0.10%;
compounds of sulfuric acid metals (conversion to sulfate ion) - 0.01%;
the calcined residue when used for the treatment of nitric acid is 0.04%.
Exactly the same requirements are observed in the production of PMS-1, 11, A copper powder (with the exception of the percentage of oxygen in the composition).
The product brands PMS-N and PMS-K should contain no more than:
The mass fraction of copper, as already mentioned, according to the standards, in all grades of electrolytic powder should be at least 99.5%.
Other characteristics
According to GOST 4960, enterprises, among other things, must comply with the particle size distribution of their products, as well as its bulk density. Both of these indicators are determined by special tables.
The bulk density of copper powders should be as follows:
PMS-V - 2.4-2.7.
PMS-K - 2.5-3.5.
1 - 1.25-2.0.
A - 1.3-1.5.
PMS-11 - 1.25-1.9.
GOST also regulates, of course, other parameters of powders:
for the PMS-V brand, the wet pressing strength should not be less than 60 kgf / cm 2 ;
PMS-B powder should have a minimum flow rate of at least 36 s.
In addition, the product brand PMS-A:
should differ in specific surface area of particles 1000 to 1700 cm / g;
must not have a specific electrical resistance above 20 · 10 Ohm · m;
must contain in its composition particles with a diameter of not more than 10 microns from 25 to 60%.
The presence of lumps or any foreign matter in the copper powder of PMU, PMS, etc., according to the rules of GOST, is not allowed. In this case, the shape of all particles of such a product should be dendrite.
What other regulations do
The main document governing the production of copper powders is GOST 4960. However, in some cases, manufacturers can be guided by other regulatory documents in the manufacture of such material.
For example, PMU ultrafine powder is often manufactured in accordance with the rules of TU 1793-001-50316079-2004. According to this document, such a product must have a chemical purity of not less than 99.999%. Its isotopic purity should be Cu65-30.91 + Cu63-69.09.
Regulates the specifications and particle shape of the PMU powder. According to this document, they should have a spherical one. In this case, the powder itself should not have a layered structure. Of course, in it, among other things, there should not be extraneous inclusions.
Packaging
Copper powder is supplied to the market for industrial use, most often in special steel drums with a plastic bag. The volume of such containers is usually equal to 25.45 dm 3 . To preserve the product during its transportation and storage, plastic bags are fastened with double linkage.
In some cases, the PMS-1 copper powder, A, B, etc., can also be delivered to the market in polypropylene soft special containers. In such containers, polyethylene liners are also provided. Packaging of this type, however, may only be used by the manufacturer by prior arrangement with the consumer.
Copper powder belongs to the fourth class of hazard. Temperature fluctuations or high humidity do not have any special negative effect on it. Therefore, such material is allowed to be transported by any means of transport.