CN107285748B - Preparation method of ceramic composite material for emulsification pump plunger - Google Patents

Abstract

A method for preparing a ceramic composite material for an emulsification pump plunger. First, alumina, hexagonal boron nitride, magnesium oxide, calcium oxide and diopside are fully mixed, and then fully mixed with mullite whiskers. Granulation, the powder is placed in a mold for isostatic pressing, then sintered into a dense alumina ceramic plunger blank, and finally processed into a ceramic plunger with precise size and precision by grinding; compared with the prior art The ceramic plunger material of the present invention can effectively improve the toughness of the ceramic plunger, reduce the friction coefficient of the plunger, improve the grinding processing type and yield of the material, and increase the service life of the ceramic plunger.

Description

A kind of preparation method of ceramic composite material for emulsifying pump plunger

technical field

The invention relates to the field of preparation of ceramic composite materials, in particular to a preparation method of a ceramic composite material for emulsifying pump plungers.

Background technique

The emulsion pumping station is one of the key equipments in the fully mechanized mining face, and its normal operation directly affects the production efficiency of the high-yield and high-efficiency working face. Due to the long working cycle of the emulsion pump, the quality requirements of its key ceramic plunger are quite strict.

In terms of wear resistance, zirconia ceramics are twice that of toughened alumina ceramics, and toughened alumina ceramics are more than 4 times that of alumina ceramics; in terms of fracture toughness, zirconia ceramics are toughened alumina ceramics. 2-3 times that of toughened alumina ceramics is about 2 times that of alumina ceramics. The performance of zirconia ceramics is most suitable for the conditions of use in coal mines, but from an economic point of view, zirconia ceramics are expensive and cost-effective, while alumina ceramics are cheap but not enough in terms of wear resistance and toughness. Therefore, the selection of toughened alumina ceramics for the plunger material of the emulsion pump is the most reasonable, and the plunger may generate local instantaneous heat during the movement process. The toughened alumina ceramics are more stable at high temperatures than zirconia.

The whiskers are ceramic single crystals with a certain aspect ratio (0.1-1.8um in diameter and 35-150um in length) and few defects. It has high strength and is a very good toughening reinforcement of ceramic matrix composites; the fiber length is several times longer than that of ceramic whiskers, and it is also a good ceramic toughening body, and the two can be combined and practical. Alumina ceramics are composite toughened with whiskers such as SiC and Si3N4 or long fibers such as C and SiC. The addition of whiskers or fibers can increase the fracture surface, that is, increase the crack propagation channel. When the residual energy of crack propagation penetrates into the fibers (whiskers), and the fibers (whiskers) are pulled out, debonded and fractured, the fracture energy is consumed or the direction of crack propagation is deflected, etc., thereby improving the toughness of the composite material. . However, when the whisker and fiber content is high, densification becomes difficult due to its arch bridge effect, resulting in a decrease in density and a decrease in performance.

For the ceramic plunger of the emulsion pump, the sliding friction and wear between the plunger and the sealing ring is an important factor affecting the sealing, and the lubrication between the plunger and the sealing ring is an important means to reduce the friction coefficient.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a method for preparing a ceramic composite material for emulsifying a pump plunger. Hexagonal boron nitride to lubricate and various sintering aids to improve sintering compactness can effectively improve the sintering compactness, toughness and lubricity of alumina ceramic plungers.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A preparation method of a ceramic composite material for emulsification pump plunger, comprising the following steps:

Step 1; Modulation of forming powder:

Alumina powder is fully mixed with hexagonal boron nitride, magnesium oxide, calcium oxide, and diopside, and then fully mixed with mullite whiskers, and the obtained powder is granulated; the granulated powder includes the following Components and parts by weight: alumina 65-90, hexagonal boron nitride 2-6, magnesium oxide 1-3, calcium oxide 1-5, diopside 1-5, mullite whisker 5-20.

Step 2; isostatic pressing;

The mixture particles obtained in step 1 are placed in a mold to form by cold isostatic pressing, the forming pressure is 200-500MPa, and the pressure holding time is 1-10min, and the obtained blank is directly roughened;

Step 3; high temperature sintering;

The obtained rough-processed body is sintered at high temperature into a densified aluminum composite body, and the high-temperature sintering temperature is 1500-1600°C. ;

Step 4; Grinding;

The compact alumina composite ceramic plunger body is ground into a ceramic plunger.

The mold in the second step is composed of an oil-resistant rubber tube sleeve, a porous cage, a mandrel and a rubber plug.

Beneficial effects of the present invention:

The invention has the advantages that the compactness and processing efficiency of the alumina ceramic can be effectively improved, the fracture toughness and lubricity of the plunger can be improved, and the alumina ceramic plunger with high density, good toughness, excellent lubricity and high dimensional accuracy can be prepared. For the purpose of using this kind of dense alumina ceramic plunger as the core component of the plunger pump, it has the advantages of long service life, wear resistance and low friction coefficient, reducing the number of downtimes for repairing and replacing the plunger and sealing sleeve, and saving engineering operation. The cost can also be extended to other alumina components.

At the same time, due to the addition of hexagonal boron nitride, the machinability of the material is effectively improved, and the grinding production efficiency is improved. After grinding, the diameter and roundness dimensional tolerance range is <0.01mm, and the surface finish is 0.2.

Detailed ways

The present invention is further described below.

Example 1

The preparation method of the present embodiment comprises the following steps:

Step 1; Modulation of forming powder:

The alumina powder is fully mixed with hexagonal boron nitride, magnesium oxide, calcium oxide and diopside, and then fully mixed with mullite whiskers. The obtained powder is fully ball-milled and mixed with water as a medium in a ceramic container, and sprayed The granulator is dried and granulated; according to the following formula in parts by weight:

Step 2; isostatic pressing;

The mixture particles obtained in step 1 were put into a special molding die composed of a mandrel, an oil-resistant rubber sleeve, a porous cage and a rubber plug, and after sealing, they were put into the oil cylinder of the cold isostatic press, and kept under the pressure of 400MPa. Press for 5 minutes to form; after demoulding, rough machining is performed first;

Step 3; high temperature sintering;

The obtained rough-processed body is sintered at high temperature into a densified aluminum composite body, and the temperature is kept at a sintering temperature of 1550 degrees for 180 minutes;

Step 4; Grinding;

The dense alumina composite ceramic plunger body is roughly ground and finely ground to make the dense alumina ceramic plunger; the relative density is 99.2%, the diameter tolerance is 0.005-0.01mm, and the surface roughness is 0.2.

Embodiment 2

The preparation method of the present embodiment comprises the following steps:

Step 1; Modulation of forming powder:

The alumina powder is fully mixed with hexagonal boron nitride, magnesium oxide, calcium oxide and diopside, and then fully mixed with mullite whiskers. The obtained powder is fully ball-milled and mixed with water as a medium in a ceramic container, and sprayed The granulator is dried and granulated; according to the following formula in parts by weight:

Step 2; isostatic pressing;

The mixture particles obtained in step 1 were put into a special molding die consisting of a mandrel, an oil-resistant rubber sleeve, a porous cage and a rubber stopper, and after sealing, they were put into the oil cylinder of the cold isostatic press, and kept under the pressure of 350MPa. Press for 10 minutes to form; after demoulding, rough machining is performed first;

Step 3; high temperature sintering;

The obtained rough-machined body is sintered at a high temperature into a densified aluminum composite material body, and the temperature is kept at a sintering temperature of 1530 degrees for 180 minutes;

Step 4; Grinding;

The dense alumina composite ceramic plunger body is roughly ground and finely ground to make the dense alumina ceramic plunger; the relative density is 99.5%, the diameter tolerance is 0.005-0.01mm, and the surface roughness is 0.2.

Embodiment 3

The preparation method of the present embodiment comprises the following steps:

Step 1; Modulation of forming powder:

The alumina powder is fully mixed with hexagonal boron nitride, magnesium oxide, calcium oxide and diopside, and then fully mixed with mullite whiskers. The obtained powder is fully ball-milled and mixed with water as a medium in a ceramic container, and sprayed The granulator is dried and granulated; according to the following formula in parts by weight:

Step 2; isostatic pressing;

The mixture particles obtained in step 1 were loaded into a special molding die composed of a mandrel, an oil-resistant rubber sleeve, a porous cage and a rubber plug, and after sealing, they were placed in the oil cylinder of a cold isostatic press, and kept under a pressure of 200 MPa. Press for 3 minutes to form; after demoulding, rough machining is performed first;

Step 3; high temperature sintering;

The obtained rough-processed body is sintered at high temperature into a densified aluminum composite material body, and the temperature is kept at a sintering temperature of 1580 degrees for 180 minutes;

Step 4; Grinding;

The dense alumina composite ceramic plunger body is roughly ground and finely ground to make the dense alumina ceramic plunger; the relative density is 98.5%, the diameter tolerance is 0.005-0.01mm, and the surface roughness is 0.2.

Embodiment 4

The preparation method of the present embodiment comprises the following steps:

Step 1; Modulation of forming powder:

The alumina powder is fully mixed with hexagonal boron nitride, magnesium oxide, calcium oxide, and diopside, and then fully mixed with mullite whiskers. The obtained powder is fully ball-milled and mixed with water as a medium in a ceramic container. The granulator is dried and granulated; according to the following formula in parts by weight:

Step 2; isostatic pressing;

The mixture particles obtained in step 1 were put into a special molding die composed of a mandrel, an oil-resistant rubber sleeve, a porous cage and a rubber plug, and after sealing, they were placed in the oil cylinder of a cold isostatic press, and kept under a pressure of 300MPa. Press for 1 minute to form; after demoulding, rough machining is performed first;

Step 3; high temperature sintering;

The obtained rough-processed body is sintered at high temperature into a densified aluminum composite material body, and the temperature is kept at a sintering temperature of 1500 degrees for 180 minutes;

Step 4; Grinding;

The dense alumina composite ceramic plunger body is roughly ground and finely ground to make the dense alumina ceramic plunger; the relative density is 99.0%, the diameter tolerance is 0.005-0.01mm, and the surface roughness is 0.2. Embodiment 5

The preparation method of the present embodiment comprises the following steps:

Step 1; Modulation of forming powder:

The alumina powder is fully mixed with hexagonal boron nitride, magnesium oxide, calcium oxide and diopside, and then fully mixed with mullite whiskers. The obtained powder is fully ball-milled and mixed with water as a medium in a ceramic container, and sprayed The granulator is dried and granulated; according to the following formula in parts by weight:

Step 2; isostatic pressing;

The mixture particles obtained in step 1 were put into a special molding die composed of a mandrel, an oil-resistant rubber sleeve, a porous cage and a rubber plug, and after sealing, they were placed in the oil cylinder of a cold isostatic press, and kept under a pressure of 500MPa. Press for 8 minutes to form; after demoulding, rough machining is performed first;

Step 3; high temperature sintering;

The obtained rough-machined body is sintered at high temperature into a densified aluminum composite material body, and the temperature is kept at a sintering temperature of 1600 degrees for 180 minutes;

Step 4; Grinding;

The dense alumina composite ceramic plunger body is roughly ground and finely ground to make a dense alumina ceramic plunger, which is roughly ground and finely ground to make a dense alumina ceramic plunger; the relative density is 99.3%, and the diameter tolerance is 99.3%. 0.005-0.01mm, surface roughness 0.2.

Claims (1)

1. The preparation method of the ceramic composite material for the emulsification pump plunger is characterized by comprising the following steps of:

step one; preparing forming powder:

fully mixing alumina powder, hexagonal boron nitride, magnesium oxide, calcium oxide and diopside, and then fully mixing the mixture with mullite whiskers to obtain powder for granulation; the granulation powder comprises the following components in parts by weight: 65-90 parts of alumina, 2-6 parts of hexagonal boron nitride, 1-3 parts of magnesium oxide, 1-5 parts of calcium oxide, 1-5 parts of diopside and 5-20 parts of mullite whisker;

step two; isostatic pressing;

placing the mixture particles obtained in the step one in a mould for cold isostatic pressing forming, wherein the forming pressure is 200 and 500MPa, and the pressure maintaining time is 1-10min to obtain a blank body;

step three; sintering at high temperature;

sintering the obtained blank at high temperature to obtain a densified aluminum composite blank, wherein the high-temperature sintering temperature is 1500-1600 ℃;

step four; grinding;

and grinding the compact alumina composite ceramic plunger blank to obtain the ceramic plunger.