The invention relates to nano praseodymium oxide lubricating oil additive

The technical problem to be solved by the invention is to provide an energy saving and environmental protection rare earth lubricating oil additive. The rare earth lubricant additive has good wear resistance and self – healing properties.
In order to solve the above technical problems, the invention provides a nano praseodymium oxide lubricating oil additive, which is characterized in that it contains nano praseodymium oxide after surface modification.

Preferably, the lubricating oil additive preparation materials include:
Nano praseodymium oxide 15wt. %;
Surfactants 85wt. %.
Preferably, the surfactant comprises Tween60, SPAN20, SPAN80 and polyether.
Preferably, the mass ratio of tween 60, Spane 20, Spane 80 and polyether is 2:1:1:3.
The invention also provides a preparation method of nano praseodymium oxide lubricating oil additive, which is characterized in that it includes the following steps:

Step 1: Mix Tween 60, Spane 20, Spane 80 and polyether at a mass ratio of 2:1:1:3 to get surfactant;
Step 2: add 15% mass fraction of nano-praseodymium oxide to 85% mass fraction of surfactant obtained in step 1, namely, get surface modified nano-praseodymium oxide, as nano-praseodymium oxide lubricating oil additive.
The invention also provides an application of nano praseodymium oxide lubricating oil additive as a multifunctional lubricating oil or grease additive.

The invention also provides a repair antiwear agent for mechanical equipment lubrication system, which is characterized in that it contains the nano praseodymium oxide lubricating oil additive.
Preferably, the machinery is large machinery used in vehicles, ships, petrochemicals or mines.

The nano praseodymium oxide lubricating oil additive in the invention is characterized by: because of the surface tension of the lubricating oil, nano praseodymium oxide particles cannot be evenly distributed in the lubricating oil, and nano particle groups may be formed to make the lubricating oil worse, so the lubricating oil additive must contain surfactants. The mixture of Tween60, SPAN20, SPAN80 and polyether was used as surfactants, and the mixing ratio was 2:1:1:3 according to the empirical formula of oil-hydrophilic. The invention has the advantages of clean process, friendly environment, simple implementation conditions and convenient for large-scale continuous production.

Compared with the prior art, the invention has the following beneficial effects:
(1) Nano praseodymium oxide lubricating oil additive obtained by the method of the invention has excellent stability, will not decompose acid and alkaline substances, and will not cause corrosion to parts;
(2) Nano praseodymium oxide surface modification to obtain anti-wear and self-healing properties of lubricating oil additives;
(3) The raw materials used in the method of the invention are commonly used industrial raw materials. The lubricating oil additive configuration method is simple and can be used for large-scale production.
(4) The lubricating oil additive of the invention has the characteristics of simple preparation method, energy saving and environmental protection, anti-wear and good self-repair performance.
The present invention is further elaborated in combination with specific embodiments. It is understood that these embodiments are intended only to illustrate and not to limit the scope of the invention. It is further understood that, after reading the material taught about the invention, a person skilled in the field may make any modification or modification of the invention, and that such equivalent forms fall within the limits of the claims attached to this application.

Implementation example 1
This embodiment provides a nano praseodymium oxide lubricating oil additive, which consists of nano praseodymium oxide after surface modification. The lubricating oil additive preparation raw materials include: nano praseodymium oxide 15wt. % and surfactant 85wt. %. The specific preparation steps of nano praseodymium oxide lubricating oil additive are as follows:

Step 1: Tween60, Span20, Span80 and polyeether (Tween60, SPAN20 and SPAN80) are all produced and provided by Guangzhou Runhua Food Co., LTD., the article numbers are 1270321, 1276121 and 1276521 respectively, and the structural formulas are: C24h46o6 (C2H4O)20, C18H34O6, C24H44O6, polyether is produced and provided by Shanghai Budding Technology Biology Co., LTD., the article number is MS15024-250G. Nano praseodymium oxide was produced by Guangdong Huizhou Ruier Chemical Technology Co., LTD., particle size of 20 ~ 30nm) was mixed with a mass ratio of 2:1:3:3 to get surfactant;

Step 2: add the mass fraction of 15% nano praseodymium oxide mass fraction is 85% in step 1 to get the surface active agent, namely for the surface modification of nanometer praseodymium oxide, nano praseodymium oxide as lubricating oil additive on first praseodymium oxide anti-wear and self-healing performance of lubricating oil additives is analyzed, and then analyze the rare earth lubricating oil additive energy saving effect.

(1) Mechanism analysis of antiwear and self-healing properties of nano-praseodymium oxide lubricating oil additive:
Friction and wear tests are carried out on four-ball friction and wear testing machine and disk pin friction and wear testing machine.

The test conditions of four-ball friction and wear test are as follows: steel ball material is GCr15, diameter 12.7mm, hardness 60HRC; First set the load of 160N, speed of 300r/min for 20s, then slowly apply pressure, reach 360N, speed to 1200r/min, continue for 60min, room temperature.

The test conditions of disc pin friction and wear test are as follows: the upper sample pin material is 416 stainless steel, and the lower sample disc is AINSIE52100 steel. The load is 260N, the rotation speed of the sample plate is 900r/min, lasting 20h, room temperature. Nano praseodymium oxide lubricating oil additive was dispersed into Castrol engine lubricating oil with a mass fraction of 0.5% and oscillated in an ultrasonic oscillator for 15min.

Table 1 lists the four ball friction and wear test results of castrol engine lubricating oil with 0.5% nano praseodymium oxide additive in test group and control group without additives. It can be seen from the table that under the condition that the load of the four-ball wear tester is 360N, the diameter of the grinding spot is reduced by 7% on average, and the friction coefficient is reduced by 23.2%. It shows that nano praseodymium oxide lubricating oil additive can improve the anti-wear performance of Castrol engine lubricating oil.

Table 1 Tribological properties of rare earth lubricating oil additives
Table 2 shows the friction and wear test results of disc pin in castrol engine lubricating oil with 0.5% nano praseodymium oxide additive in the experimental group and without additives in the control group. The mass loss of disc is reduced by 12.3% and roughness is reduced by 73.4%. The friction coefficient was reduced by 4.1%, which reflected the improved anti-wear performance of the additives in terms of mass loss, friction coefficient and roughness changes. FIG. 1 and 2 are the optical microscope pictures of oil spots in the two groups respectively, with magnification of 100. From FIG. 1 and 2, it can be seen that the scratches in the experimental group are relatively slight, indicating that the additives improve the wear condition. FIG. 3 and 4 respectively show the surface topography of abrasive spots. The scratches in the control group are deep, indicating a severe wear process, while the scratches in the experimental group are gentle, indicating a mild wear process, which proves that the additives improve the wear condition. The maximum depth of the disc wear was 3778.7nm in the control group and 2605.3nm in the experimental group, indicating that the additive had an obvious filling effect on the rough surface. If the contour roughness of the wear marks is defined as the variance of the depth of the wear marks, the average contour roughness of the wear marks is 160.77 in the control group and 124.829 in the experimental group, which is an improvement of 12.9%. The absolute depth of wear marks on the disk with additive is smaller than that without additive, which shows the improvement of wear resistance. The change of the depth of the wear marks is relatively gentle, indicating that nano praseodymium oxide lubricant additive can fill and repair the friction surface.

Table 2 Test results of disc pin friction
(2) Analysis of energy saving effect of nano-praseodymium oxide lubricating oil additive:

The energy-saving test was carried out on the diesel engine produced by Shanghai Diesel Engine Co., LTD. Diesel engine model is 4135, cylinder diameter 135mm, stroke 150mm, compression ratio 17, dimension running power 66KW /1500rpm, total running time 1000h.
The test conditions of energy saving test: room temperature 3.5℃, relative humidity 53%, oil consumption measurement method of fuel consumption meter is quality method.

Table 3 shows the diesel engine test results at different time and working points in the control group without praseodymium oxide lubricating oil additive. Table 4 shows the diesel engine test results at different times and working points under the condition that 0.5% nano praseodymium oxide lubricating oil additive is added in the experimental group.

Table 3 Diesel engine test results of the control group at different times and operating points
Table 4 Diesel engine test results of experimental group at different time and working points

It can be seen from the test results that the fuel consumption rate of diesel engine with nano-praseodymium oxide additives decreases in different degrees under different loads. The fuel saving rate of diesel engine under 70%, 80% and 90% loads is 5.77%, 5.75% and 5.57% respectively. The energy saving effect is obvious.

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