铁基自润滑合金硫化钼形成规律

利用中频感应炉炼制四种不同钼、硫含量的钢,通过SEM观察组织并结合XRD分析物相,研究合金中的硫化钼形成规律. 结果表明:Mo的质量分数为1.5%时,只能形成 FeS,极少量的Mo以Fe3Mo2形式存在;Mo为6.5%时,Mo仍以Fe3Mo2的形式存在;Mo达到11%时,虽有少量的MoS2形成,但多数Mo与Fe形成化合物Fe3Mo2;Mo达到19.5%时生成较多的MoSx;Mo低于10%时很难形成钼的硫化物;退火有利于MoSx的形成,但未发现纯的MoS2生成. 由此初步认为:MoSx是FeMoS化合物分解析出的,是亚稳的;在合金中起细化晶粒作用的V,Nb和Ti有过强的硫亲和力,不利于钼的硫化物形成;脱氧的铝也应少加.

Evolution of molybdenum sulfide in iron-based self-lubrication alloys

Iron-based sulfides self-lubricating alloys with different contents of molybdenum were prepared with a medium-frequency induction furnace. The evolution of molybdenum sulfide in these alloys was studied by scanning electron microscope and X-ray diffractometer. The results showed that only FeS formed in the alloy and Mo presented as Fe3Mo2 with a Mo mass fraction of 1.5 %. When the mass fraction of Mo was 6.5%, no MoS2 formed, and Mo still presented as Fe3Mo2. When the mass fraction of Mo was 11%, only a small quantity of MoSx could form and great majority of Mo and Fe formed the compound Fe3Mo2. MoSx formed remarkably when the mass fraction of Mo was up to 19.5 %. It is difficult for molybdenum sulfides to be formed with Mo mass fractions less than 10 %. Annealing treatment is favorable for MoSx formation, but no pure MoSx was found in the above alloys. MoSx is a metastable phase formed through the decomposition of Fe-Mo-S compounds. V, Nb and Ti, which are used to decrease grain size in the alloys, are disadvantageous for the formation of molybdenum sulfides due to their strong bonding force to sulfur. Aluminum used as deoxidant should be added in a small amount.