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

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

Inactive Publication Date: 2006-02-01
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 Ag and the material is mixed by weight; the above mixture is ball-milled for 16 hours with gasoline medium or inert gas protection under the condition that the ball-to-material ratio is 10:1 and the rotation speed is 1200rps, so that the powder is uniform. Mixed and ball milled into composite powder with particle size less than 10μm, in which Cr 2 O 3 , BaF 2 , CaF 2 The grain size is less than 200nm; add 3% polyvinyl alcohol by weight of the composite powder as a binder, and then mix it with water or alcohol in a weight ratio of 8:1 to make a slurry. The slurry is coated on the friction contact plane or journal surface that requires high temperature resistance to form a coating, and then the coating is dried at 50 ° C; the flat coating is pr...

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 Ag and the material is mixed by weight; the above mixture is ball-milled for 5 hours with gasoline medium or inert gas protection under the condition that the ball-to-material ratio is 16:1 and the rotation speed is 900rps with a high-energy ball mill to make the powder uniform. Mixed and ball milled into composite powder with particle size less than 10μm, in which Cr 2 O 3 , BaF 2 , CaF 2 The grain size is less than 200nm; adding 0.5% polyvinyl alcohol by weight of the composite powder as a binder, and then mixing it with water or alcohol in a weight ratio of 5:1 to make a slurry, which will be made into a slurry. The slurry is coated on the friction contact plane or the surface of the journal that needs high temperature resistance to form a c...

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%, and the balance of Ag is mixed by weight; the above mixture is ball-milled for 20 hours with gasoline medium or inert gas protection under the condition that the ball-to-material ratio is 12:1 and the rotation speed is 1100rps with a high-energy ball mill to make the powder uniform. Mixed and ball milled into composite powder with particle size less than 10μm, in which Cr 2 O 3 , BaF 2 , CaF 2 The grain size is less than 200nm; adding 1.0% polyvinyl alcohol by weight of the composite powder to the above-mentioned composite powder as a binder, and then mixing it with water or alcohol in a weight ratio of 2:1 to make a slurry. The slurry is coated on the friction contact plane or journal surface that requires high temperature resistance to form a coating, and t...

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PUM

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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 Other solid self-lubricating materials have lost their lubricating effect when the temperature is higher than 300℃, TiN, TiAlN, Cr 3 C 2 When the temperature is higher than 450 °C, the coating cannot be used due to its poor oxidation resistance. Therefore, the NASA Green Research Center in the United States successfully developed a high temperature (room temperature ~ 650 °C) self-lubricating PS304 coating on the basis of PS300 from 1995 to 1997. US Patent: US5866518). The coating is a NiCr (80 / 20) alloy matrix, which contains 3 self-lubricating phases, Cr 2 O 3 , Ag and BaF 2 / CaF 2 of co-crystals (62 / 38). Among them, NiCr alloy matrix (total weight: 60wt%) provides good high temperature oxida...

Claims

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Application Information

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Patent Type & Authority Applications(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
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