一种镍－铬－硫合金的研制及其摩擦学特性

Preparation and Tribological Performance Of a Ni-Cr-S Alloy

为了解决特殊工况下运转的机器设备在较宽温度范围内的润滑问题，已有多种镍基、铁基高温自润滑材料问世。但因这些材料的综合性能不够好，尚难满足有关场合下的实用要求。因此，在以往研制Ｎｉ－Ｃｒ合金的基础上，通过对多种含硫量不同的Ｎｉ－Ｃｒ－Ｓ合金中硫含量与材料摩擦学性能及机械性能之关系的考察，研制成功了一种综合性能比较好的Ｎｉ－Ｃｒ－Ｓ三元合金，其含硫量为５％（ｗｔ）。这种合金在常温下的抗压强度为０．８８ＧＰａ，冲击强度为０．３３×１０５Ｎ·ｍ／ｍ２，在５００℃下的摩擦系数为０．３１，磨损率为１５．８×１０（－１４）ｍ３／（Ｎ·ｍ）。组织结构分析发现，合金中硫与铬形成了多种ＣｒｘＳｙ［ｘ／ｙ＝（２／３）－１］型的化合物。这些化合物既能在合金摩擦面富集成膜，又能在偶件摩擦面形成转移膜，因而这种Ｎｉ－Ｃｒ－Ｓ合金具有自润滑性能，此外，合金中的ＣｒｘＳｙ化合物还对偶件材料高速钢表面的元素铁具有催化氧化作用，这也是其具有自润滑性能的重要原因。

To meet the lubrication requirements of some special devices operated in a wide hightem peratu re range,kinds of nickel based and iron based high te mperature self-lubricating materialshave been developed.However,some practical lubrication requirements can not be satisfied bythose materials,because the comprehensive mechanical and physical properties of the materials arenot good enough.Thus,Ni-Cr-S alloy,which is produced using a intermediate induction meltingand precise casting process,has been developed.The effect of sulpher eontent on the mechanicaland tribological properties of the alloy were studied.A Ni-Cr-S alloy containing 5%(wt)sulpherwas found to have the good Comprehensive properties. The compressive strength of the Ni-Cr-Salloy is 0.88GPa,the impact strength is 0.33 × 105N·m/m2,the friction coefficient at 500℃ is0.31,the wear rate is 15.8×10(-14)m3/(N·m).Structure analysis found that sulpher in the alloycombined with Cr forming some CrxSy[x/y=(2/3)-1] type compounds.These compounds areenriched and films formed on the friction surfaces of the alloy and the mating materials.Thereforethe alloy has selflubrication performance,Additionally,the compounds have catalytic effect on theoxidation of iron on the surface of the mating material(high speed steel).This is also a reason forthe self-lubricating performance of the alloy.