RU2387680C2 - Method of preparing nano-composite material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method involves mixing nanofiller with binder, mechanical activation of the obtained mixture and final moulding of the mixture. The powdered filler and binder undergo combined preliminary mechanical activation to obtain a concentrate. The concentrate is a powdered mixture of components with ratio binder: filler equal to 50:50. Further, the obtained concentrate is mixed with binder in amount of 100 pts. wt binder per 0.1-2.0 pts. wt concentrate to obtain a second mixture. This mixture undergoes traditional mixture in a bead mill for a period of time sufficient for obtaining a homogeneous mixture. The powdered mixture is then hot-moulded at pressure and temperature at which the mixture turns into a fluid. Further, the mixture is kept under these conditions until complete solidification. The binder used is powdered polypropylene.

EFFECT: method enables to obtain antifriction material, characterised by high strength properties and wear resistance, elasticity and low brittleness.

1 cl, 7 ex, 6 dwg, 1 tbl

Description

The present invention relates to the field of nanotechnology and can be used to obtain anti-friction materials used in friction units, in sliding bearings, as part of structural materials of rotating turbine shafts, oil drilling systems.

A known method of producing a composite material, according to which the mixture is obtained by joint mechanical activation of a pre-ground filler and a binder (RF patent No. 2160856, IPC F16C 33/14, publ. 12/20/2000).

As a powdery filler in the known method, a composition of natural minerals based on complex oxygen-containing compounds of magnesium, silicon, iron, molybdenum, sulfur is used.

The disadvantages of this method include the lack of the ability to obtain high physical and mechanical properties of the material, such as elasticity and fluidity.

As the closest in technical essence to the claimed method is known for producing a composite material by mixing pre-ground powder filler with a binder, mechanically activating the mixture, with the final molding of the mixture (RF patent No. 2296139, IPC C08J 5/16, publ. March 27, 2007) .

The disadvantages of the prototype include the lack of the ability to obtain high physical and mechanical properties of the material, such as elasticity and fluidity, tensile strength and at the same time low brittleness.

The task of the inventors is to develop a method for producing nanocomposite antifriction material, characterized by high strength characteristics and wear resistance, elasticity, low fragility.

A new technical result provided by using the proposed method is to provide the possibility of improving the physicomechanical parameters of the nanocomposite, such as elasticity and fluidity, tensile strength, and tribological characteristics while maintaining density, high wear resistance and reducing brittleness.

These tasks and a new technical result are achieved by the fact that in the known method for producing a nanocomposite antifriction material used in friction units, including mixing the nanofiller with a binder, mechanical activation of the resulting mixture, final molding of the mixture, according to the invention, the powder nanofiller and binder are preliminarily treated by mechanical activation with obtaining a concentrate in the form of a powdery mixture of components with a ratio of components of a binder her: filler 50:50, then add the resulting concentrate to the binder at the rate of choice for every 100 parts by weight a binder of 0.1-2.0 parts by weight concentrate to obtain a second mixture, which is processed by traditional mixing in a ball mill for an estimated time sufficient to achieve a homogeneous state of the mixture, and the subsequent molding of the powder mixture is carried out by heat pressing at a pressure and temperature at which the mixture begins to flow and then the mixture is kept under these conditions until fully cured, with powdered polypropylene being used as a binder.

The proposed method is illustrated as follows.

Powdered polypropylene is initially prepared as a binder, to which the required amount of nanofiller (for example, nanoclay, quasicrystals of complex composition) is added with the following stated ratio of components: binder: filler 50:50. To do this, the source material in the form of a powder is placed in a mechanical activator and, in the mode of mechanical activation, the mixture is treated for a calculated time. Then, the obtained concentrate is isolated by sieving in the form of a powder mixture with particle sizes in the nanometer range and this mixture is dosed in the claimed range of ratios into the prepared powdery polypropylene as a binder based on the choice for every 100 parts by weight a binder of 0.1-2.0 parts by weight concentrate. Then, the obtained second mixture is mixed in a ball mill according to the traditional regime for the estimated time, followed by molding by thermocompression at pressure and the temperature at which the mixture begins to flow, followed by exposure to the specified conditions until complete curing.

The graphical images show the changes in the studied physical and mechanical parameters depending on the mass of the nanofiller. So, the optimal amounts of nanofiller were determined for density, tensile strength, tensile modulus, elongation in tension, friction coefficient, wear rate. A graph of the dependence of the density of the nanocomposite on the filler content is shown in FIG. 1, a graph of the dependence of the tensile strength of the nanocomposite on the filler content is shown in FIG. 2, a graph of the tensile modulus of the nanocomposite on the filler content is shown in FIG. tensile nanocomposite from the filler content is shown in figure 4, a graph of the coefficient of friction of the nanocomposite on the filler content is shown in figure 5, the graph The intensity of wear of the nanocomposite from the filler content is shown in Fig. 6.

When conducting parallel studies on the example of curing polypropylene in the initial state, a decrease in the physical, mechanical and tribological parameters of the material was shown. Similarly, when reproducing the conditions of the prototype, the level of these indicators is lower than in the claimed method.

As experiments have shown, when a nanofiller is introduced into the powdery material proposed in the binder method in another way, it is not possible to obtain a homogeneous mixture due to premature setting of the molding mixture and its uneven subsequent curing. In addition, re-mixing of the concentrate contributes to a comprehensive and uniform distribution of the nanofiller, due to which the maximum homogenization of the mixture is achieved. At the same time, it was shown that both the type of filler and the concentration of nanofiller affect the increase in the physicomechanical and tribological parameters of samples prepared by the claimed method. The experimental data are given in table. one

Thus, the use of the proposed method improved the physical and mechanical properties of the nanocomposite, such as elasticity and fluidity, tensile strength, and tribological parameters while maintaining density, high wear resistance and reducing brittleness.

The possibility of industrial implementation of the proposed method is confirmed by the following examples.

Example 1. In laboratory conditions according to the proposed method, the process of forming pure polypropylene was tested, the obtained samples were tested, the results of which are given in table. one.

Example 2

In laboratory conditions, the proposed method for producing a nanocomposite material using the planetary mechanical activator MPF-1 was tested, in which the mechanical activation mode was used, while the rotation speed was set to at least 1000 s ^-1 . In a binder sample in the form of powdered polypropylene in an amount of 50 parts by weight add a sample of nanoclay in the amount of 50 parts by weight The resulting composition is placed in a mechanical activator and activated in the above mode. The mixture is activated on a mechanical activator for a calculated time sufficient to grind the components and achieve a homogeneous state of the mixture, which under the conditions of this example is 30 minutes. Then the resulting concentrate is sieved through a sieve with a mesh size of 063. In a binder sample in the form of powdered polypropylene in an amount of 100 parts by weight add a portion obtained from the mechanical activation of the concentrate in an amount of 0.1 wt.h. The resulting composition is placed in a ball mill filled with balls, and activated for the estimated time sufficient to achieve a homogeneous state of the mixture, which under the conditions of this example is 14 hours. Then, the resulting concentrate is sieved through a sieve with a mesh size of 063 and poured into a restrictive form. In the process of thermocompression, the traditional mode is used, which is characteristic for the pressing of polypropylene. Samples are cut from the finished billet and the physical, mechanical and tribological characteristics are determined. The measurement data are summarized in table 1.

Example 3. In the conditions of example 2, the mechanical activation of the powdered binder (polypropylene) and nanofiller (nanoclay) is carried out at a ratio of them, respectively, parts by weight, 50:50 to obtain a concentrate. The mixture is mechanically activated for 30 minutes. To a hitch 100 parts by weight binder add 2 parts by weight concentrate. The resulting composition was stirred for 14 hours in a mixer with balls. The resulting composition is sieved through a sieve with a mesh size of 0.63 mm and poured into the mold. The pressing process is carried out according to the traditional mode. Samples are cut from the finished workpiece and the physical, mechanical and tribological characteristics are determined. The measurement data of the obtained samples are summarized in table 1.

Example 4. Spend without mechanical activation, mixing and forming a mixture of 100 wt. including powdered polypropylene and 0.05 parts by weight nanoclay. The mixture is stirred in a mixer with balls for 14 hours. The resulting composition is sieved through a sieve with a mesh size of 0.63 mm and poured into the mold. The pressing process is carried out according to the traditional mode. Samples are cut from the finished workpiece and the physical, mechanical and tribological characteristics are determined. The measurement results are presented in table 1.

Example 5. In the conditions of example 4, a mixture of 100 wt.h. binder and 1.0 parts by weight nanoclay. Samples are cut from the finished workpiece and the physical, mechanical and tribological characteristics are determined. The measurement results are presented in table 1.

Example 6. In the conditions of example 4, a mixture of 100 wt.h. binder and 1.0 parts by weight ultrafine nanodiamonds. Samples are cut from the finished workpiece and the physical, mechanical and tribological characteristics are determined. The measurement results are presented in table 1.

Example 7. In the conditions of example 4, a mixture of 100 wt.h. binder and 1.0 parts by weight quasicrystals, which are used as single-phase quasicrystalline alloys of the following composition (in general form): Al - Cu - Fe or Al - Cu - Cr.

Samples are cut from the finished workpiece and the physical, mechanical and tribological characteristics are determined. The measurement results are presented in table 1.

Visually, on micro-sections of the finished nanocomposite (according to examples 1-7), ordered clusters of filler nanoparticles were revealed, each of which is covered with a binder of the first mixture in the mass of the binder of the second mixture, which can be schematically represented as follows:

{granule (composition: nanoparticle + 1st binder) is placed: in the 2nd binder}.

Table 1 shows that with an increase in the binder size of the nanofiller (nanoclay, ultrafine diamond, quasicrystals), wear, friction coefficient, elasticity, and tensile strength decrease, while curing a pure binder results in materials with lower tribological and strength indices.

As can be seen from the above examples, experimentally confirmed to ensure the increase of physico-mechanical and tribological parameters when using all the conditions and operations of the proposed method.

Claims (1)

A method of obtaining a nanocomposite antifriction material used in friction units, comprising mixing a nanofiller with a binder, mechanically activating the resulting mixture, final molding the mixture, characterized in that the powder nanofiller and binder are pretreated together by mechanoactivation to obtain a concentrate in the form of a powdery mixture of components with a ratio of components of the binder : filler 50:50, then add the resulting concentrate to the binder based on the choice for each 100 parts by weight of s a binder of 0.1-2.0 parts by weight concentrate to obtain a second mixture, which is subjected to traditional mixing in a ball mill for an estimated time sufficient to achieve a homogeneous state of the mixture, and the subsequent molding of the powder mixture is carried out by heat pressing at a pressure and temperature at which the mixture begins to flow and then the mixture is kept under these conditions until fully cured, with powdered polypropylene being used as a binder.

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