查看更多>>摘要：The MCrAlY coating has been potential candidate for the parts applied in friction and corrosion conditions,and CNTs(carbon nanotubes)are expected to improve the service performance of coatings owing to high lubrication and low chemical reactiv-ity.In this work,a systematic investigation on the tribological and corrosion properties of CoCrAlYTaSiC-xCNTs coatings deposited by laser melting was analyzed.Results showed that the coatings had good-quality without typical metallurgical defects.The CNTs addition homogenized and refined the microstructure of coating,and also improved the tribological and corrosion properties.As the CNTs content changed from 0 to 4 wt％,the wear rate of coating decreased from 16.23 × 10-3 to 7.58 × 10-3 mg m-1,the jcorr of coating decreased from 4.13 × 10-4 to 1.23 × 10-4 A cm-2,and the Rct values increased from 12.69 to 25.07 Ω cm2.
查看更多>>摘要：The oxidation behavior and kinetics of Ti2AlC-20vol.％TiB2 composite at 600-900 ℃ in air were investigated.The results showed that the oxidation kinetics of the composite followed a logarithmic law within the given temperature range,which indicated that the composites had excellent oxidation resistance.The selective oxidation of Al in Ti2AlC was greatly enhanced,which facilitated the formation of a continuous and dense protective layer of Al2O3.Meanwhile,the existence of molten B2O3 inhibited the outward diffusion of Ti and inward diffusion of oxygen,which prevented the growth of anatase TiO2 at 600 ℃ and rutile TiO2 at 700-900 ℃.Therefore,the incorporation of TiB2 completely inhibited the abnormally rapid oxidation of bulk Ti2AlC at 600 ℃ and improved its oxidation resistance at 700-900 ℃.
查看更多>>摘要：In aero-engines,abrasive coatings are typically utilized to protect the blade tip from excessive wear caused by the harder abradable sealing coating and thereby improve the sealing performance of engines.Therefore,a Ni/cBN abrasive coating was prepared on titanium alloy using electrodeposition.The high-speed rubbing tests with a linear velocity of 350 m/s and different incursion rates were performed to investigate the effect of the Ni/cBN abrasive coating on the wear behavior against NiCrAl/diatomite seal coating.Results showed that melting wear and adhesive transfer occurred on the bare blades,causing the bare blade to suffer excessive wear.While the Ni/cBN abrasive coating exhibited superior wear resistance and cutting performance.The cBN grits pullout,the abrasion of Ni matrix and transfer of seal coating to the cBN grits were the main wear mechanism of the Ni/cBN abrasive coating.Additionally,it was found that the relationship between the incursion rate and high-speed rubbing behavior is quite different for the bare blade and Ni/cBN coating.The reason for the difference in wear behavior of bare blade and Ni/cBN coating at different incursion rates was discussed in detail.
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