RU2257401C2 - Solid lubricating coating - Google Patents

Abstract

FIELD: production of lubricating materials.

SUBSTANCE: the invention is pertaining to the field of production of solid lubricating materials. The invention provides, that the coating contains a powdery filler composed of the following components (in mass %): silicon compounds - 30-43 %, magnesium compounds - 21-35 %, iron compounds - 25-45 %, accompanying minerals and bindings. The technical result is improvement of tribotechnical characteristics, a decrease of wearing of friction pairs.

EFFECT: the invention ensures improved tribotechnical characteristics, decreased wearing of friction pairs.

4 tbl, 2 dwg

Description

The invention relates to the field of chemistry and metallurgy, in particular to lubricant compositions of inorganic material, and can be used in the implementation of energy-saving technologies in geological exploration, mining, engineering, energy, transport, etc.

A solid lubricating coating is known, containing up to 3.3% of a natural mineral mixture based on serpentinite, including by weight 30-40% silicon compounds, 25-35% magnesium compounds, 15-20% iron compounds and other concomitants with a dispersion of 0.01-1 , 0 μm and 96.7% organic binder, which ensures that a servo film is formed by a tribotechnical composition when placed between the contacting surfaces and the running-in, reducing the friction coefficient and wear of parts (see RF patent No. 2035636, class F 16 C 33/14).

The disadvantages of the known coatings are: the formation of abrasive impurities that are not associated with the formation of tribological properties and worsen them, the need for mechanical activation to ensure uniformity of composition.

A solid lubricating coating is known that contains from 0.5 to 2.0% of a natural mineral mixture based on serpentinite, including by weight 36-43% silicon compounds, 21-27% magnesium compounds, 10.5-14.5% iron compounds and other associated with a dispersion of up to 10 microns and 98-99.6% of an organic binder, which allows to abandon its mechanical activation, replacing it with homogenization (see RF patent No. 2043393, class C 10 M 125/04) - prototype.

The disadvantages of this coating are similar to the disadvantages of the coating given in the analogue.

The invention consists in the following. In the mineral serpentinite, crystal chemistry distinguishes tetrahedral layers of silicon compounds and octahedral layers of magnesium compounds. In the octahedral layers, a process of energy transformation is possible: the conversion of hydrogen into helium, the energy yield of which, according to astrophysics, can reach 27.7 MEV.

When the serpentinite is heated to 600 ° C, the reaction shown in Fig. 1 takes place. As a result of this reaction, finely dispersed forsterite and silica are formed with melting points of 1890 and 1470 ° C, respectively. When the hardness of serpentinite on the Mohs scale is about 2.5-3.0, the hardness of forsterite and silica formed in the reaction shown in Fig. 1 reaches 6.5-7.0. A large number of iron compounds significantly changes the nature of the processes that occur in this case are determined by the reactions shown in figure 2. The reaction products are olivine, fayalit, water and free hydrogen. The hardness of olivine and fayalite is comparable to the hardness of forsterite, but they have lower transformation temperatures (1250-1400 and 1100-1250 ° C, respectively), therefore these reactions are more preferable, and free hydrogen is an energy source for these transformations. With a sufficient content of iron compounds in the mineral mixture, the course of the reactions indicated in FIG. 2 can end when a local temperature reaches 1200-1400 ° C on the walls of the contacting surfaces (in the prototype 1500 ° C).

For the full course of reactions, the iron content in the mineral mixture should be at least 81% of the mass of serpentinite included in its composition (in natural mixtures, the content of iron compounds does not exceed 21%).

In order to reduce the influence of the abrasive admixture formed during the mineralization of the mineral mixture and to ensure the completeness of the formation of olivine and fayalite, the iron content in the powder filler of the proposed solid lubricant coating is brought to 25-45%. As additives to natural mixtures, powdered iron used in powder metallurgy can be used. The increase in the iron content in serpentinite-based mineral mixtures is supported by the positive correlation of the tribological properties of the coating with the magnetic susceptibility of the mineral mixture.

In the process of running-in due to the release of energy associated with the conversion of hydrogen to helium, local sintering of forsterite, olein, fayalite, quartz, etc. grains with the material of the contacting surfaces occurs and they swell as a result of the penetration of helium by water vapor and melts under pressure into pores and microcracks opening upon deformation under the influence of the applied load. The process is accompanied by the formation of sliding mirrors and a change in the geometry of the contacting surfaces (reduction of gaps, filling of free zones, etc.); therefore, it must be monitored.

The iron content in the mineral mixture of the coating and its dispersion should be set taking into account the requirements for contacting surfaces, their materials, condition. The larger they are, the sooner the process is going on.

To apply the coating, the mineral mixture is mixed with a binder (organic or water) until a homogeneous paste is obtained, suitable for application by brush, oiler, gravity or under pressure. The prepared lubricant composition is placed between the contacting surfaces and run in continuously or discretely with the registration of the load and temperature until there are tendencies for their stabilization or decrease in the slew rate. Possible preliminary tests on friction machines, similar to those described in the description of the prototype. After running-in, the contacting surfaces are washed and regular grease is applied to them.

Tests of friction pairs on a centrifugal machine (diverging disks on the shaft of an engine rotating at a speed of 3000 rpm in a fixed tube) showed the following: when a lithol was applied once to a lubricant disk, the friction pair operating time before “setting” was 3.5 min; when 50% by weight of fillers in the form of oxides of silicon, magnesium and aluminum were introduced into lithol, the working time of the friction pair before “setting” was, respectively, 1, 3, 9 minutes. When 50% by weight of the filler in the form of serpentenite was introduced into the lithol, the friction pair without “setting” worked for 65 minutes and was stopped after reaching a temperature of + 60 ° С on the pipe. After preliminary running-in of the disks in the tube with lithol containing a 50% by mass mixture of serpentenite with carbonyl iron (60 and 40%, respectively), they dry, without “setting” and visible changes in the contact surfaces, burnt the surface of the tube that was not subjected to pre-treatment.

Testing of these mineral fillers on an axial friction machine (3 fixed sectors - a rotating disk from Art. 20 and 40, respectively) at the TsKTI named after I.I.Polzunova repeated the data of previous experiments. As criteria for the effectiveness of the tribotechnical properties of the considered mineral fillers, the time to reach the temperature in the contact zone of the order of + 50 ° C or “setting”, the increase in energy consumption were chosen.

Initial data and test results are given in Tables 1-4 of the appendix.

When grooving the contact surface of a rotating disk with sectors, it was not possible to pass it with an ordinary cutter (tempering of the cutting edge).

Analysis of the experimental results allows us to draw the following conclusions:

- when mineral fillers are introduced into a lubricant containing magnesium, silicon and iron compounds, the formation of a stable cermet coating on the metal surface by friction can be achieved only under the conditions defined by the equations presented in figures 1, 2 of the description of the invention;

- mixtures of natural minerals at any ratio cannot ensure the fulfillment of these conditions, because they do not compensate for the negative effect of the abrasive components formed during their decomposition and the stability of the coating, which can only be achieved by bringing the iron content in them to 25-45%.

Table 1 Test results of a friction pair with a single application of lithol lubricant into the contact zone Working time, min N rpm T ₁ , ° C T ₂ ° C T ₃ ° C W, W R kg Note 0 0 17 17 17 0 8 Grappling twenty 500 29th thirty 27 80 8 40 500 40 41 40 160 8 table 2 Test results of a friction pair with a single application to the zone of contact of the lubricant lithol with 10% serpentenite by weight Working time, min N rpm T ₁ , ° C T ₂ ° C T ₃ ° C W, W R kg Note 0 500 thirty thirty thirty 40 0 5 500 35 34.5 35.5 90 8 25 500 39 43 41 90 8 45 500 43 47 45 110 8 65 500 46 52 49 120 8 Grappling Table 3 Test results of a friction pair with a single application of lithol with 10% by weight of a mixture of serpentenite and iron into the contact zone of a lubricant Working time, min N rpm T ₁ , ° C T ₂ ° C T ₃ ° C W, W R kg Note 0 0 24 24 24 0 0 After testing, the contact surface of the friction pair in all experiments without scoring 10 400 36 37 37 100 6 twenty 420 39 40 40 80 6 thirty 420 40 40 40 70 6 40 420 41 41.5 41.5 75 8 fifty 420 42 42 42 75 8 60 420 42 42.5 42 70 8 70 420 44 44 43.5 80 10.5 80 420 44.5 45 44 80 10.5 90 420 45 45 45 80 10.5 100 420 49 49.5 49 100 fifteen 110 420 53 53 53 110 fifteen 120 420 55 55 55 118 fifteen 130 420 57 57 56 112 fifteen 140 420 58.5 58.5 58 120 fifteen

Table 4 Test results of a pair of friction with a single application in the zone contact lubricant lithol with 10% by weight of a mixture of quartz and iron in a ratio of 1: 2 Working time, min N rpm T ₁ , C T ₂ , C T ₃ , C W, W R kg Note 0 0 19 19 19 0 0 Without setting 3 500 19 19 19 90 0 7 500 24 24 24 100 8 twenty 500 36 36 36 100 8 40 500 49.5 49.5 49.5 85 8 60 500 40 40.5 40 85 8 80 500 40 40.5 40 80 8 100 500 40 40 40 80 8

Claims (1)

A solid lubricating coating containing a powdery filler, comprising 30-43% by weight of silicon compounds, 21-35% of magnesium compounds, associated minerals and a binder, characterized in that the filler additionally contains 25-45% iron.

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