Preparation Process And Microstructure Properties Of The Wear Resistant Coating On Joint

In order to prepare the coating materials suitable for the joint wear-resistant belt,Ni/Al coating,FeAl coating and NiCrBSi coating were prepared by atmospheric plasma spraying The cross-sectional microstructure morphologies of the coatings were studied.Two kinds of NiCrBSi coatings with different Fe content were prepared by air plasma spraying in-situ induction remelting process.Microstructures and properties of the coatings were investigated,so that the best bonding coating was determined.The NiCrBSi?Fe?-TiN composite coatings with different Ti contents were prepared by reactive plasma spraying in situ induction remelting process,and the effect of Ti content on microstructures and properties of the composite coatings were researched,the working coating of the wear-resistant belt was determined.Meanwhile,the microstructures and properties of WC-Ni reinforced NiCrBSi coatings were studied.The results showed that:?1?NiCrBSi coating was the most suitable material for induction remelting among the Ni/Al coating,FeAl coating and NiCrBSi coating.The induction remelting has successfully achieved metallurgical bonding between Ni-based alloy and matrix interface,and eliminated the inherent defects,such as lamellar structures,microcracks and unmelted particles produced by plasma spraying.When the content of Fe was more than 14%?NiCrBSi?Fe??,the second phases in Ni-based coating changed from lamellar distribution into fine dispersed distribution.As a consequence,microhardness,adhesion strength and wear resistance of the coatings were significantly improved.?2?The NiCrBSi?Fe?-TiN composite coating deposited by reactive plasma spraying was mainly composed of?-Ni,FeNi₃ and Cr_1.12Ni_2.88 in the Ni-based alloy and TiN ceramic phase.The TiN ceramic phases of boundary occurred decomposition after remelting and reactd with Ni-based phases to form TiNi alloy.The combination of the remelted composite coating and metal matrix transformed into metallurgical bonding,and the bonding strength was significantly increased.?3?The variation of Ti content has little effect on the hardness value of NiCrBSi?Fe?-TiN composite coating,while the influence on the weibull modulus was very apparent.When the Ti content was 30wt.%,composite coating had the most uniform microstructure and most stable mechanical property.Hence,the wear resistance was the best.?4?Compared with as-sprayed composite coating,the electron work function of remelted composite coating was higher,and there was a obvious transition layer between the coating and substrate interface.Induction remelting significantly improved the sliding wear resistance and erosion wear resistance of the composite coating.?5?WC-Ni phase could be well wetted by Ni-based phase in the NiCrBSi/WC-Ni composite coating.Microhardness and wear resistance of the NiCrBSi coating were significantly enhanced with the addition of WC-Ni,but the adhesion strength decreased and the porosity increased slightly.