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Method for preparing self-lubricating coat in use for high temperature

A high-temperature self-lubricating and coating technology, applied to coatings, devices for coating liquid on surfaces, special surfaces, etc., can solve the problems of short service life, low strength, peeling off of coatings, etc., and achieve low cost , good sintering performance

Inactive Publication Date: 2007-07-25
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the thickness of the PS304 coating will increase by 3-5% during the long-term high-temperature process, the PS304 coating must be annealed at a high temperature above 540°C for 150 hours to stabilize the size and microstructure and improve the strength of the coating. PS304 coating The highest strength of the coating is only 30MPa, and the low strength of the coating is the main factor leading to the short service life of the coating and the failure of the coating due to peeling off
[0004] Therefore, the PS304 coating has serious deficiencies such as severely uneven microstructure and low strength, which may easily cause the coating to be peeled off prematurely during use and lose its lubricating effect.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0008] Example 1: First, Ni, Cr, Cr with a purity greater than 99.0% and a particle size of 30 μm to 200 μm 2 o 3 、BaF 2 , CaF 2 , Ag powder according to Ni: 40%, Cr: 15%, Cr 2 o 3 : 20%, BaF 2 : 10%, CaF 2 : 5%, the balance is the material that is Ag and mixes by weight; The above-mentioned mixture adopts high-energy ball mill to be 10: 1 in ball-to-material ratio, and rotating speed is 16 hours with gasoline medium or inert gas protection ball milling under the condition of 1200rps, makes powder uniform Mix and ball mill into a composite powder with a particle size of less than 10 μm, in which Cr 2 o 3 、BaF 2 , CaF 2 The grain size of the compound powder is less than 200nm; add polyvinyl alcohol with 3% weight of the composite powder to the above composite powder as a binder, and then mix it with water or alcohol at a weight ratio of 8:1 to make a slurry. The slurry is coated on the frictional contact plane or the journal surface that needs high temperature resista...

Embodiment 2

[0009] Example 2: First, Ni, Cr, Cr with a purity greater than 99.0% and a particle size of 30 μm to 200 μm 2 o 3 、BaF 2 , CaF 2 , Ag powder according to Ni: 50%, Cr: 5%, Cr 2 o 3 : 16%, BaF 2 : 5%, CaF 2 : 1%, the balance is the material that is Ag and mixes by weight; The above-mentioned mixture adopts high-energy ball mill to be 16: 1 at the ball-to-material ratio, and the rotating speed is 900rps under the condition of 900rps with gasoline medium or inert gas protection ball milling 5 hours, make powder uniform Mix and ball mill into a composite powder with a particle size of less than 10 μm, in which Cr 2 o 3 、BaF 2 , CaF 2 The grain size of the compound powder is less than 200nm; add 0.5% polyvinyl alcohol by weight of the composite powder to the above composite powder as a binder, and then mix it with water or alcohol at a weight ratio of 5:1 to make a slurry, and the made The slurry is coated on the frictional contact plane or the journal surface that needs h...

Embodiment 3

[0010] Example 3: First, Ni, Cr, Cr with a purity greater than 99.0% and a particle size of 30 μm to 200 μm 2 o 3 、BaF 2 , CaF 2 , Ag powder according to Ni: 45%, Cr: 10%, Cr 2 o 3 : 5%, BaF 2 : 8%, CaF 2 : 4%, the balance is the material that is Ag and mixes by weight; The above-mentioned mixture adopts high-energy ball mill to be 12: 1 at the ball material ratio, and the rotating speed is 1100rps under the condition of 1100rps with gasoline medium or inert gas protection ball milling 20 hours, make powder uniform Mix and ball mill into a composite powder with a particle size of less than 10 μm, in which Cr 2 o 3 、BaF 2 , CaF 2 The grain size of the compound powder is less than 200nm; add polyvinyl alcohol with 1.0% of the weight of the composite powder to the above composite powder as a binder, and then mix it with water or alcohol at a weight ratio of 2:1 to make a slurry, and the made The slurry is coated on the frictional contact plane or the journal surface tha...

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Abstract

A refractory self-lubricating coated layer is prepared through proportionally mixing Ni, Cr, Cr2O3, BaF2, CaF2 and Ag high-energy ball grinding, preparing slurry, coating on the target surface, baking, cold isostatic pressing for compacting it, and sintering at 800-1200 deg.C for 1-3 hr. Its strength is more than 40 MPa.

Description

technical field [0001] The invention belongs to the field of high temperature resistant friction and wear materials, in particular to a preparation method of a high temperature self-lubricating coating. Background technique [0002] Due to the traditional graphite, PTFE, MoS 2 Solid self-lubricating materials such as TiN, TiAlN, Cr have lost their lubrication when the temperature is higher than 300 °C 3 C 2 Such coatings cannot be used due to poor oxidation resistance when they are higher than 450°C. Therefore, NASA Green Research Center in the United States successfully developed high temperature resistant (room temperature to 650°C) self-lubricating PS304 coatings on the basis of PS300 in 1995-1997 ( US Patent: US5866518). The coating is a NiCr (80 / 20) alloy matrix, which contains three self-lubricating phases, Cr 2 o 3 , Ag and BaF 2 / CaF 2 The eutectic (62 / 38). Among them, the NiCr alloy matrix (accounting for the total weight: 60wt%) provides good high temperatu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09D129/00C09D1/00B05D3/08B05D5/08
Inventor 丁春华杨志懋宋晓平丁秉钧周敬恩
Owner XI AN JIAOTONG UNIV