几种含硫镍基高温自润滑合金的研究

The Effects of Alloying Elements on the Tribological Behaviours of the High Temperature, Self-Lubricating Nickel-Base Alloys Containing Sulphur

作者用中频感应炉熔炼了5种Mo、S添加量相同的含S镍基合金,并在其自行设计制造的销-盘式高温摩擦试验机上考察了它们的摩擦系数和磨损率随温度的变化规律。物相分析结果表明,合金中生成的硫化物在不含Cr时主要是MoS_2,而在合金含5％(ωt)和10％(ωt)Cr时生成的硫化物分别为CrMo_2S_4和Cr_3S_4。因此,含Cr合金在较低温度下的摩擦系数明显比不含Cr合金的低,其在较高温度(600℃)时的摩擦系数也仍然能够保持与不含Cr合金相当的低值。在合金中加入Fe和Co仅起固溶强化作用而不影响生成的硫化物的类型。Co的加入及其添加量的增大,减小了合金在高温下的磨损。合金含C量的增大,使合金中生成的碳化物增多,也减小了合金的磨损。本文根据试验比较选择报道的Ni-Mo-10Fe-10Cr-10Co-S-0.8C合金在20—600℃温度范围内的摩擦系数低、磨损小,并且具有一定的机械强度,是一种实用性能比较好的高温自润滑合金。

Five nickel-base alloys which have the same contents of sulphur and molybdenum were prepared by intermediate frequency induction melting. The friction coefficient and wear rate of the alloys under the different temperature conditions was measured in air on a pin-on-disc tribometer. The preliminary results of X-ray diffraction and microstructure analysis indicated that when chromium content is 0,5 and 10 percent the sulphide formed in the alloys is mainly MoS2, CrMo2S4 and Cr3S4, respectively. Therefore, comparing with that of the alloys without chromium, the friction coefficients of the alloys containing chromium significantly decrease at lower temperature. On the other hand, the friction coefficients of the alloys containing chromium also keep the value similar to that of the alloys not containing chromium at higher temperature (600℃). Adding alloy elements, iron and cobalt, only combine with matrix of the alloys as solid solution-strengthing elements but seem not to affect the type of the sulphide formed in the alloys. With the increasing of the carbon content in the alloys, the amounts of the carbide formed in the alloys increase and the wear of the alloy may be decreased. Test results indicate that one of the alloys (Ni-Mo-10Fe-10Cr-10Co-S-0. 8C) has the good mechanical strength and tribological properties, so it is an applicable alloy over a wide range of temperature from 20 to 600℃.