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a self-lubricating 3 no 4 /ag composites

A composite material and self-lubricating technology, which is applied in the field of self-lubricating Si3N4/Ag composite materials, can solve the problems of field limitation, high friction coefficient wear rate, and unsatisfactory tribological properties of pure silicon nitride, so as to reduce production and processing costs, Effects of improving fracture toughness and improving wear resistance

Active Publication Date: 2019-09-20
LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the tribological properties of pure silicon nitride under unlubricated conditions are not ideal, with high friction coefficient (0.5~1) and wear rate (10 −5 mm 3 N −1 m −1 ~10 −2 mm 3 N −1 m −1 ), so that the field of its application has been greatly limited

Method used

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  • a self-lubricating <sub>3</sub> no <sub>4</sub> /ag composites
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  • a self-lubricating <sub>3</sub> no <sub>4</sub> /ag composites

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Effect test

Embodiment 1

[0015] According to the mass percentage, first weigh 92wt% of Si 3 N 4 The powder was placed in a teflon ball mill, and 8wt% AgNO was added to it 3 The aqueous solution was uniformly mixed at a speed of 300 rmp for 15 hours; the liquid mixture was heated in a beaker and stirred until the water vapor was completely evaporated, and then sieved to obtain a powder mixture with a particle size of 50-100 μm. The powder is then loaded into graphite molds and sintered in a plasma sintering furnace. The sintering parameters are: the degree of vacuum is lower than 5×10 -1 Pa, heating rate 100ºC / min, sintering temperature 1700ºC, pressure 30MPa, holding time 10min. After sintering, the furnace was cooled to room temperature to obtain Si. 3 N 4 / Ag composite. its Si 3 N 4 The SEM photo of / Ag composite after sintering is as follows: figure 1 shown.

Embodiment 2

[0017] According to the mass percentage, first weigh 84wt% of Si 3 N 4 The powder was placed in a teflon ball mill, and 16wt% AgNO was added to it 3 The aqueous solution was uniformly mixed at a speed of 300 rmp for 15 hours; the liquid mixture was heated in a beaker and stirred until the water vapor was completely evaporated, and then sieved to obtain a powder mixture with a particle size of 50-100 μm. The powder is then loaded into graphite molds and sintered in a spark plasma sintering furnace. The sintering parameters are: the degree of vacuum is lower than 5×10 -1 Pa, heating rate 100ºC / min, sintering temperature 1700ºC, pressure 30 MPa, holding time 10 min. After sintering, the furnace was cooled to room temperature to obtain Si. 3 N 4 / Ag composite. Use HT-1000 high temperature friction and wear tester to conduct friction and wear experiments, the dual ball is Si with a diameter of 4mm 3 N 4 Ceramic ball, load is 10N, sliding linear velocity is 0.13m / s, friction...

Embodiment 3

[0019] According to the mass percentage, first weigh 76wt% of Si 3 N 4 powder in a teflon ball mill, and add 24wt% AgNO to it 3 The aqueous solution was uniformly mixed at a speed of 300 rmp for 15 hours; the liquid mixture was heated in a beaker and stirred until the water vapor was completely evaporated, and then sieved to obtain a powder mixture with a particle size of 50-100 μm. The powder is then loaded into graphite molds and sintered in a spark plasma sintering furnace. The sintering parameters are: the degree of vacuum is lower than 5×10 -1 Pa, heating rate 100ºC / min, sintering temperature 1700ºC, pressure 30MPa, holding time 10min. After sintering, the furnace was cooled to room temperature to obtain Si. 3 N 4 / Ag composite. The hardness is measured by a Vickers high temperature hardness tester. The test conditions are: load 10kg, load duration 10s, and test temperature 25ºC. Fracture toughness was calculated using the indentation method. Table 1 is the Si des...

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Abstract

The invention discloses a self-lubricating Si3N4 / Ag composite material. The composite material is prepared by the method which comprises the following steps that ball milling and mixing are carried out on Si3N4 powder with the mass percent of 76-92wt% and an AgNO3 aqueous solution with the mass percent of 8-24wt%, then a liquid mixture is put into a beaker to be heated and stirred until water vapor completely volatilizes, powder is dried and then is sieved so as to obtain a powder mixture with the particle size of 50-100 microns; then the powder mixture is put into a graphite jig and is put ina discharge plasma sintering furnace to be sintered, wherein the sintering parameters are as follows: the vacuum degree is 10<-2>-10<-1>Pa, the heating rate is 100 DEG C / min, the sintering temperature is 1650-1700 DEG C, the pressure is 30-40MPa, and the heat preservation time is 10-15min; and after sintering is finished, cooling is carried out to reach the room temperature along with a furnace so as to obtain the Si3N4 / Ag composite material. The Si3N4 / Ag composite material has excellent mechanical property and tribological property (low frictional wear), so that the material has continuous and lasting self-lubricating performance within a temperature range of 25 DEG C to 600 DEG C, and therefore the integrated design of the structure / the lubricating function of the ceramic composite material can be realized.

Description

technical field [0001] The present invention relates to a self-lubricating Si 3 N 4 / Ag composite, in Si 3 N 4 The material obtained by introducing elemental silver into the matrix has good fracture toughness under the premise of maintaining high hardness, and the tribological properties of the material are greatly improved in the temperature range from room temperature to 600ºC, especially at 200ºC, The material has the lowest coefficient of friction. Background technique [0002] Lubricating materials are indispensable basic materials in modern machinery and equipment, and play an important role in the national economy and national defense construction. With the development of high-end equipment, higher requirements are placed on the limit of mechanical components, especially in some extreme environments, such as high temperature or marine environment, it is more urgent to have higher mechanical properties and tribological properties of materials demand. Among them, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C29/16C22C1/05B22F3/105
Inventor 乔竹辉刘炯杰杨军尹兵孙奇春朱圣宇程军
Owner LANZHOU INST OF CHEM PHYSICS CHINESE ACAD OF SCI