Method for improving lubricating performance of lubricating oils

Abstract

A method for improving lubricating performance of lubricating oils is provided and includes: adding copper phosphate with a porous structure into a base oil, a mass percent of the copper phosphate with the porous structure to the base oil is 0.0001% ˜50%, the porous structure is one of a foam porous structure and a porous nanoflower structure. The copper phosphate with the porous structure is obtained by adding a divalent copper salt solution into an alkaline disodium hydrogen phosphate solution or alkaline phosphoric acid buffer solution and then separating a precipitate. When a ratio of a concentration of a divalent copper ion to that of a phosphate ion is 1:0.1 to 400, the porous structure is porous foam or nanoflower. The porous structure can be well dispersed in the lubricating oil for 1 hour. After adding the lubricating oil, excellent friction reduction and anti-wear is achieved.

Claims

1. A method for improving lubricating performance of lubricating oils, comprising: adding a divalent copper salt solution into an alkaline phosphoric acid solution for reaction, and after the reaction, separating a precipitate to obtain copper phosphate with a porous structure; wherein a ratio of a concentration of a divalent copper ion in the divalent copper salt solution to that of a phosphate ion in the alkaline phosphoric acid solution is 1:0.1 to 400; and adding the copper phosphate with the porous structure into a base oil, wherein a mass percent of the copper phosphate with the porous structure to the base oil is in a range of 0.0001% to 50%, and the porous structure is one of a foam porous structure and a porous nanoflower structure.

2. The method for improving the lubricating performance of lubricating oils according to claim 1, wherein the base oil is one of a mineral oil, a semi synthetic oil, a synthetic oil, and a vegetable oil.

3. The method for improving the lubricating performance of lubricating oils according to claim 1, wherein the copper phosphate does not contain crystal water; or the copper phosphate contains 1 to 3 number of crystal water.

4. The method for improving the lubricating performance of lubricating oils according to claim 1, wherein the alkaline phosphoric acid solution is one of a disodium hydrogen phosphate solution and an alkaline phosphoric acid buffer solution.

5. The method for improving the lubricating performance of lubricating oils according to claim 4, wherein the divalent copper salt solution is one of a copper sulfate solution, a copper chloride solution, and a copper nitrate solution.

6. The method for improving the lubricating performance of lubricating oils according to claim 4, wherein the alkaline phosphoric acid buffer solution is obtained by mixing sodium dihydrogen phosphate with dibasic sodium phosphate.

7. The method for improving the lubricating performance of lubricating oils according to claim 4, wherein the precipitate is separated by using one of a decantation method, a gravity sedimentation method, a filtration method, and a centrifugation method.

8. The method for improving lubricating performance of lubricating oils according to claim 4, wherein the potential of hydrogen (PH) of the alkaline phosphoric acid solution is in a range of 7 to 12.

9. The method for improving lubricating performance of lubricating oils according to claim 1, wherein the copper phosphate with the porous structure has a molecular formula as follows: Cu.sub.3(PO.sub.4).sub.2.Math.XH.sub.2O, where X is 0 to 3; and a form of the copper phosphate with the porous structure is solid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a scanning electron microscope (SEM) picture of copper phosphate with a porous structure (i.e., foam porous structure) according to an embodiment 1.

(2) FIG. 2 illustrates a SEM picture of copper phosphate with a porous structure (i.e., nanoflower structure) according to an embodiment 2.

(3) FIG. 3 illustrates a schematic diagram of friction coefficients of copper phosphate with a porous structure (i.e., nanoflower structure) with different mass fractions as lubricating oil additives.

(4) FIG. 4 illustrates a schematic diagram of comparisons of friction coefficients and wear rates of copper phosphate with a porous structure (i.e., nanoflower structure) with different mass fractions as lubricating oil additives.

(5) FIG. 5A illustrates a 3D white light picture of a wear mark of pure poly-alpha-olefin 4 (PAO4) lubricating oil.

(6) FIG. 5B illustrates a 3D white light picture of a wear mark of PAO4 lubricating oil added with the copper phosphate with a porous structure (i.e., nanoflower structure) of the embodiment 2.

(7) FIG. 6 illustrates a schematic diagram of a lubrication mechanism of a foam porous structure of copper phosphate.

(8) FIG. 7 illustrates a schematic diagram of a lubrication mechanism of nanoflowers of copper phosphate.

DETAILED DESCRIPTION OF EMBODIMENTS

(9) In order to better understand the above purposes, features and advantages of the disclosure, the disclosure will be further described in detail below in combination with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the disclosure and the features in the embodiments can be combined with each other without conflict.

(10) Many specific details are set forth in the following description to facilitate a full understanding of the disclosure. However, the disclosure can also be implemented in other ways different from those described here. Therefore, the scope of protection of the disclosure is not limited by the specific embodiments disclosed below.

Embodiment 1

(11) A method for improving lubricating performance of a lubricating oil. Copper phosphate with a porous structure is added to a base oil, and the components by the mass percent include: 0.55 g of the copper phosphate with the porous structure, and 5 g of the PAO4 base oil.

(12) (1) Preparation of the Copper Phosphate with the Porous Structure (i.e., Foam Porous Structure)

(13) After 1 mL of 0.2 mol/L copper sulfate solution is mixed with 400 mL of 0.2 mol/L disodium hydrogen phosphate, a precipitate is obtained by centrifugation, the precipitate is the copper phosphate with the foam porous structure. After the copper phosphate with the foam porous structure is dried in an oven at 65° C., 0.55 g of the dried copper phosphate with the foam porous structure is weighed and added to 5 g of the PAO4 base oil.

(14) The SEM picture of the copper phosphate with the foam porous structure is shown in FIG. 1.

(15) (2) Determination Testing of Friction-Reduction and Antiwear Properties

(16) Performing a ball disk reciprocating friction test on a friction and wear tester provided by Rtec: a GCr15 steel ball with a diameter of 6.3 mm and a TA5 titanium alloy disk with a diameter of 4*4 cm are subject to reciprocating friction.

(17) Test conditions: a load is 10 N, and a speed is 8 Hz (a linear speed is 128 mm/s).

(18) (3) Comparative Analysis of Results of Friction-Reduction and Antiwear Properties

(19) Compared with the pure PAO4 (without any additives), the friction coefficient is reduced by 73%, and the wear rate is reduced by 99%.

Embodiment 2

(20) A method for improving lubricating performance of a lubricating oil. Copper phosphate with a porous structure is added to a base oil, and the components by the mass percent include: 0.55 g of the copper phosphate with the porous structure, and 5 g of the PAO4 base oil.

(21) (1) Preparation of the Copper Phosphate with the Porous Structure (i.e., Nanoflower Structure)

(22) After 1 mL of 0.2 mol/L copper sulfate solution is mixed with 100 mL of 0.2 mol/L disodium hydrogen phosphate, a precipitate is obtained by centrifugation, the precipitate is the copper phosphate with the nanoflower structure. After the copper phosphate with the nanoflower structure is dried in an oven at 65° C., 0.55 g of the dried copper phosphate with the nanoflower structure is weighed and added to 5 g of the PAO4 base oil, and ultrasonic dispersion for 30 min.

(23) The SEM picture of the copper phosphate with the nanoflower structure is shown in FIG. 2.

(24) (2) Determination Testing of Friction-Reduction and Antiwear Properties

(25) Performing a ball disk reciprocating friction test on a friction and wear tester provided by Rtec: a GCr15 steel ball with a diameter of 6.3 mm and a TA5 titanium alloy disk with a diameter of 4*4 cm are subject to reciprocating friction.

(26) Test conditions: a load is 10 N, and a speed is 8 Hz (a linear speed is 128 mm/s).

(27) (3) Comparative Analysis of Results of Friction-Reduction and Antiwear Properties

(28) Compared with the pure PAO4, the friction coefficient is reduced by 74%, and the wear rate is reduced by 99%.

(29) The friction coefficient is shown in FIG. 3, a comparison between the friction coefficient and the wear rate is shown in FIG. 4, a 3D white light picture of a wear mark of the pure PAO4 is shown in FIG. 5A, and a 3D white light picture of a wear mark of the PAO4 lubricating oil added with the copper phosphate with the nanoflower structure is shown in FIG. 5B.

Embodiment 3

(30) A method for improving lubricating performance of a lubricating oil. Copper phosphate with a porous structure is added to a base oil, and the components by the mass percent include: 0.55 g of the copper phosphate with the porous structure, and 5 g of the PAO4 base oil.

(31) (1) Preparation of the Copper Phosphate with the Porous Structure (i.e., Foam Porous Structure)

(32) After 1 mL of 0.2 mol/L copper sulfate solution is mixed with 400 mL of 0.2 mol/L disodium hydrogen phosphate, a precipitate is obtained by centrifugation, the precipitate is the copper phosphate with the foam porous structure. Petroleum ether is used to clean the precipitate several times without drying, and then the precipitate and the petroleum are directly mixed with the PAO4. An oil sample containing the copper phosphate with the porous structure was prepared by string at 90° C. for 2 hours to volatilize the petroleum ether. The mass percent of the copper phosphate with the porous structure is calculated according to an initial weight of the oil sample and a weight after heating treatment. A certain mass of the PAO can also be added to adjust the mass percent.

(33) (2) Determination Testing of Friction-Reduction and Antiwear Properties

(34) Performing a ball disk reciprocating friction test on a friction and wear tester provided by Rtec: a GCr15 steel ball with a diameter of 6.3 mm and a TA5 titanium alloy disk with a diameter of 4*4 cm are subject to reciprocating friction.

(35) Test conditions: a load is 10 N, and a speed is 8 Hz (a linear speed is 128 mm/s).

(36) (3) Comparative Analysis of Results of Friction-Reduction and Antiwear Properties

(37) Compared with the pure PAO4, the friction coefficient is reduced by 75%, and the wear rate is reduced by 99%.

Embodiment 4

(38) A method for improving lubricating performance of a lubricating oil. Copper phosphate with a porous structure is added to a base oil, and the components by the mass percent include: 0.55 g of the copper phosphate with the porous structure, and 5 g of the PAO4 base oil.

(39) (1) Preparation of the Copper Phosphate with the Porous Structure

(40) After 1 mL of 0.2 mol/L copper sulfate solution is mixed with 200 mL of 0.2 mol/L disodium hydrogen phosphate, a precipitate is obtained by centrifugation, the precipitate is the copper phosphate with the porous structure (i.e., foam porous structure and nanoflower structure). After the copper phosphate with the porous structure is dried in an oven at 65° C., 0.55 g of the dried copper phosphate with the porous structure is weighed and added to 5 g of the PAO4 base oil.

(41) (2) Determination Testing of Friction-Reduction and Antiwear Properties

(42) Performing a ball disk reciprocating friction test on a friction and wear tester provided by Rtec: a GCr15 steel ball with a diameter of 6.3 mm and a TA5 titanium alloy disk with a diameter of 4*4 cm are subject to reciprocating friction.

(43) Test conditions: a load is 10 N, and a speed is 2 Hz (a linear speed is 36 mm/s).

(44) (3) Comparative Analysis of Results of Friction-Reduction and Antiwear Properties

(45) Compared with the pure PAO4, the friction coefficient is reduced by 45%, and the wear rate is reduced by 81%.

Embodiment 5

(46) A method for improving lubricating performance of a lubricating oil. Copper phosphate with a porous structure is added to a base oil, and the components by the mass percent include: 0.1 g of the copper phosphate with the porous structure, and 5 g of the PAO4 base oil.

(47) (1) Preparation of the Copper Phosphate with the Porous Structure

(48) After 1 mL of 0.2 mol/L copper sulfate solution is mixed with 200 mL of 0.2 mol/L disodium hydrogen phosphate, a precipitate is obtained by centrifugation, the precipitate is the copper phosphate with the porous structure. After suction filtration and separation, washing the copper phosphate with the porous structure with ethanol for several times, then drying the copper phosphate with the porous structure in an oven at 65° C., weighing the dried copper phosphate with the porous structure of 0.1 g, and adding it to the PAO4 base oil of 5 g.

(49) (2) Determination Testing of Friction-Reduction and Antiwear Properties

(50) Performing a ball disk reciprocating friction test on a friction and wear tester provided by Rtec: a GCr15 steel ball with a diameter of 6.3 mm and a TA5 titanium alloy disk with a diameter of 4*4 cm are subject to reciprocating friction.

(51) Test conditions: a load is 10 N, and a speed is 8 Hz (a linear speed is 36 mm/s).

(52) (3) Comparative Analysis of Results of Friction-Reduction and Antiwear Properties

(53) Compared with the pure PAO4, the friction coefficient is reduced by 35%, and the wear rate is reduced by 58%.

Embodiment 6

(54) A method for improving lubricating performance of a lubricating oil. Copper phosphate with a porous structure is added to a base oil, and the components by the mass percent include: 0.55 g of the copper phosphate with the porous structure, and 5 g of the PAO4 base oil.

(55) (1) Preparation of the Copper Phosphate with the Porous Structure (i.e., Nanoflower Structure)

(56) 56 mL of 0.2 mol/L sodium dihydrogen phosphate is mixed with 144 mL of 0.2 mol/L dibasic sodium phosphate to obtain 200 mL of 0.2 mol/L phosphate buffer solution with PH being 7.2.

(57) After 50 mL of 0.2 mol/L copper sulfate solution is mixed with 200 mL phosphate buffer solution, a precipitate is obtained by centrifugation, the precipitate is the copper phosphate with the foam porous structure. After the copper phosphate with the foam porous structure is dried in an oven at 65° C., 0.55 g of the dried copper phosphate with the foam porous structure is weighed and added to 5 g of the PAO4 base oil.

(58) (2) Determination Testing of Friction-Reduction and Antiwear Properties

(59) Performing a ball disk reciprocating friction test on a friction and wear tester provided by Rtec: a GCr15 steel ball with a diameter of 6.3 mm and a TA5 titanium alloy disk with a diameter of 4*4 cm are subject to reciprocating friction.

(60) Test conditions: a load is 10 N, and a speed is 8 Hz (a linear speed is 128 mm/s).

(61) (3) Comparative Analysis of Results of Friction-Reduction and Antiwear Properties

(62) Compared with the pure PAO4 (without any additives), the friction coefficient is reduced by 70%, and the wear rate is reduced by 99%.

(63) The disclosure provides the method for improving the lubricating performance of the lubricating oil. The divalent copper salt solution is added to the disodium hydrogen phosphate solution or the alkaline phosphoric acid buffer solution, and the precipitate is separated to obtain the copper phosphate. When the ratio of the concentration of the divalent copper ion to the concentration of the phosphate ion is 1:0.1 to 400, the microstructure of the copper phosphate is porous foam or nanoflowers. Due to the large specific surface area and strong adsorption, the porous structure can be well dispersed in the lubricating oil. After adding the lubricating oil, excellent friction reduction and anti-wear effect is achieved. Compared with the pure lubricating oil, the friction coefficient is reduced by more than 75% and the wear rate is reduced by more than 99%. The experimental method is simple and easy, with a wide range of raw materials. The experimental process is mild and simple, does not need intense experimental methods such as high temperature, and does not involve any organic reagents. The device for the disclosure is simple, conforms to the green environmental protection route, and can be widely applied to lubricating oil additives.

(64) The above is only illustrated embodiments of the disclosure and are not intended to limit the disclosure. For those skilled in the art, the disclosure may have various changes and variations. Any amendment, equivalent replacement, improvement, etc. made within the spirit and principles of the disclosure shall be included in the protection scope of the disclosure.