【摘 要】
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The graphite-ceramic containing titanium-Fe based alloy clad coatings were synthesized in situ on Q235 steel substrates by a reactive plasma cladding process using Fe901, Ti, h-BN and graphite (C) pow
【机 构】
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College of Mechanics and Materials, Hohai University, Nanjing 211100, China;Nantong Hohai University
【出 处】
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第十一届全国表面工程大会暨第八届全国青年表面工程学术会议
论文部分内容阅读
The graphite-ceramic containing titanium-Fe based alloy clad coatings were synthesized in situ on Q235 steel substrates by a reactive plasma cladding process using Fe901, Ti, h-BN and graphite (C) powders as raw materials (The mass of Fe901, Ti and h-BN reactive powders is M and the Fe901 accounts for 80wt.%M, Ti/h-Bn mole ratio is 3/2.). The effects of the graphite powder addition amount (0-11.25wt.%M) on the bonds between the coating and substrate along with the microstructure and microhardness of the clad coatings were investigated. The results show that all of the clad coatings are metallurgical bonded with the substrates. When the addition amount of graphite powder is greater than or equal to 3.75wt.%M, the clad coatings contain graphite lubricating phase and the content of graphite lubricating phase increases with the increase of the graphite powder addition amount. The coating mainly consists of Fe-Cr, Fe3C, TiC, Ti8C5, TiN0.3, Ti2N, TiB2 and graphite phases at the graphite powder addition amount of 7.5wt.%M. The addition of graphite powder can depress the formation of titanium borides, titanium nitrides and iron borides. The titanium carbides precipitates are dispersed in the matrix of the clad coatings mainly in block or flower-like shape, which depends on the graphite powder addition amount. The microhardness of clad coating increases firstly and then decreases with the increase of the graphite powder addition amount. The clad coating has the highest microhardness which can reach up to 1518HV when the graphite powder addition amount is 7.5wt.%M. The microhardness change of the coatings with the graphite powder addition amount can be mainly attributed to the combined action of the changes of the ceramic reinforcements (titanium carbides and Fe3C), the content of graphite soft phase and the degree of reactions during plasma cladding process.
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