| Ferrous powder metallurgical materials possess enormous potential market and have been developed rapidly. Recently, the more and more ferrous P/M materials instead of a part of wrought steels and casting irons are used to manufacture high performance structure components, such as automotive gears, camshafts and connecting rods, which would be difficult and expensive to generate by machining. However, the tribological and mechanical properties of P/M materials are limited by their residual porosity. To widen application field of P/M materials, it is very essential to improve its tribological properties based on increasing its density level. In this paper, ferrous P/M materials with different composition were prepared, and their surfaces treated by high-frequency induction quenching and wide-band laser hardening techniques. As a result, surfaces with high hardness and good wear resistance were obtained. The application field of powder metallurgical technology is widened and properties are improved. In this work, we prepared different composition C-Cr-Ni-Mo-Cu series ferrous P/M materials with density 6.7g/cm3 by common pressing-sinter technique. The designed range of component is C0.45～0.55%, Cr0.5～2.5%, Ni1～3%, Mo0.85%, Cu1%～3%. We studied the effect of suppress pressure, sinter temperature and sinter times on density, hardness and structure of the materials in the course of preparation. Ultimately, we obtained optimal processing parameter: suppress pressure 600MPa, sinter temperature 1200℃, sinter times 60 minutes. In order to improve surface properties of the materials, high-frequency induction quenching and wide-bond laser quenching techniques were used in this test. We studied the effect of processing parameter of the two surface treatment techniques on microhardness. Finally, we obtained optimal surface treatment processing parameter: high-frequency induction quenching output power 26.1kW; laser quenching output power 3.2kW, scanning speed 8mm/s.The properties of materials are decided by their inner structure. So we studied the structure and general properties of ferrous P/M materials, and discussed the strengthen mechanism of the two surface treatment processing. The results show that the metallographic structure of sintered state ferrous P/M materials is ferrite, pearlite. Surface strengthened ferrous P/M materials show a kind of layered structure. From the surface to the center, surface quenched materials can be divided into three layer. The first layer is complete hardened layer made up of fine martensite and remained austenite. The second layer is the transition layer which microstructures are martensite, ferrite and cementite. The third layer is matrix which microstructure is ferrite and pearlite. The study also showed that the microhardness and thickness of hardened layer for laser quenching ferrous P/M materials reaches HV0.3 690～849 and 1.2～1.9mm; the microhardness and thickness of hardened layer for high-frequency induction quenching ferrous P/M materials reaches HV0.3 598～678 and 0.7～1.3mm which are lower laser quenching materials. The primary reasons of high-frequency induction quenching strengthen are the formation of remained press-stress in the hardened layer, fine martensite grain, more martensite content and dispersion strengthen. The mostly reasons of laser surface quenching strengthen are superfine grain, high martensite content, martensite containing high dislocation density and high carbon content.For use in tribological applications,it is very important that make certain the wear resistance of ferrous P/M materials and the influence rules on it. So friction and wear properties of ferrous P/M materials were studied emphatically in this test,and its wear mechanisms were discussed in detail. Dry sliding wear tests were performed using a MG-2000 type pin-disk wear apparatus. The factors affecting the friction and wear tests of ferrous P/M materials are mostly alloy composition, the experimental loads,sliding speeds and times. The curves of friction and wear of ferrou...
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