ABSTRACT
With the excellent wear resistance, corrosion resistance, and high hardness characteristics,thermal spray Cr2O3 ceramic coatings apply to special work environment, such as high temperature,corrosion and wear . The thermal stress of coatings is small during the process of friction, and the coatings are not prone to serious fracture.So they have a broad application prospect in the field of tribologyand be used widely in aerospace, biological engineering, electronic information, building and other fields. In practical applications, the friction and wear is still one of the important factors leading to the invalid Cr2O3 ceramic coatings. Therefore, the processing technology of ceramic coating Cr2O3, friction and wear properties and mechanism is of great significance.
The spraying powder used in this article was mixed powder,which is made by the Cr2O3 powder and glass ceramic glaze with the mass ratio of 65%, 80%, 85%, 95%,100%, sintered 900℃, ball milled, and sieved 200 mesh. The power was spraied on the 45 steel, respectively by the CP - 3000 type subsonic gun.Then the ceramic coatings were sintered in the resistance furnace until 1066 ℃ . The friction experiments of Cr2O3 ceramic coatings was done at room temperature.The morphology of coatings surfaces before and after wear were analyzed, and the friction and wear performance was studied with the scanning electron microscope (SEM),asana microscope, electron energy spectrum (EDS), and other means. The wear resistance of Cr2O3 ceramic coatings was simulated by ANSYS software.The modle was about individual particles in different flat rate on coatings with the tangential friction force.The stress distribution of particle and matrix interface was analyzed.
The stress distribution on matrix interface of different flat rates of particles were compared,and the fall off form of particles on these coatings through the analysis.
The experimental results show that:
(1) The friction and wear performance Cr2O3 ceramic coatings of were strengthened with the increase of spraying distance ,when the spraying distance was 150 mm-150 mm. The Optimum parameters of thermal spraying were that compressed air pressure was 0.36 MPa, the oxygen pressure was 0.5 MPa,acetylene pressure was 0.05 MPa, the preheating temperature was 400 ℃ and spraying distance was 150 mm.
(2) With the adding amount of glass glaze ,both the mass loss and mass loss of Cr2O3 ceramic coatings were reduced first and increased after. The experimental results showed that friction and wear performance of Cr2O3 ceramic coatings were the best when the proportion was about 95%.
(3) The mass loss of Cr2O3 ceramic coatings was reduction first and increased after with the increase of load.And it was increased with the increase of the time.The results showed that and the influence of time on the quality loss was greater.
(4) The better flattened degree of the particles on coatings , the better friction and wear properties of Cr2O3 ceramic coatings were.
(5) The wear mechanism of Cr2O3 ceramic coatings was combied with mild abrasive wear and slight micro-breakout .
(6) The interfacial normal stress and shear stress of the flattening particles were smaller when the they were weared by the tangential friction force.In this situation,the particle was not easy to appear spalling, and the coating was showed good wear-resistant performance.
Key words:Cr2O3 ceramic coatings; Glass glaze; Thermal spraying; Friction and wear;ANSYS
本站文章未经允许不得转载；如欲转载请注明出处，北京桑尧科技开发有限公司网址：http://en.sunspraying.com/
|
