| In this thesis, a novel kind of steel bond hard alloy cladding materials with outstanding hardness, excellent wear and corrosion resistance and high cladding/substrate bonding strength was developed by vacuum liquid phase sintering technique, and the influence of B and Mo on the performance of the steel bond hard alloy cladding materials was studied. The cladding material was applied in the surface of the machine accessories, and good effects were obtained.Five types of cladding materials have been developed successfully on the sides of steel for the first time, which were designated M, 3B, 4B, 5B and 3BMo respectively. The basic volume fraction of hard phase and binder phase, the contents of alloy elements B and Mo, and the adhesive PVB in claddings were determined.The technology process of the preparation of the cladding materials were established, which included four parts: the technology of the preparation of the slurry; disposal technology of the steel substrate; molding mode of the cladding formation and the sintering technology of the cladding materials.The liquid phase sintering technique was used for sintering of cladding materials. During sintering, the vacuum in furnace keeps 10×10-2～10×10-3Pa, The temperature is elevated from room temperature to 400℃at a speed of 10℃/min, and holds for 30 min, After that , the temperature is raised to sintering temperature, and holds for 30 min, the temperature is further elevated to 1000℃at a speed of 5℃/min, and holds for 30min. Finally, the samples are cooled in the furnace naturally. The elevated rate of temperature is 5℃/ min.The sintering temperature of five types cladding materials was determined, and the influence of the B and Mo on sintering temperature was analyzed. The results indicated that the sintering temperature of cladding material was almost 50℃lowered compared with that without B and heightened as more and more B added. When Mo was added on the base of B, the sintering temperature of cladding material was 25℃higher compared with that without Mo. The mechanical properties of the steel bond hard alloy cladding materials such as hardness and bending strength were investigated. The effects of B and Mo on hardness and bending strength were investigated in detail. The Rockwell hardness and Vickers hardness of cladding materials containing B were both higher than that of cladding material M without B and the hardness kept increasing with more and more B containing in the cladding, and the Rockwell hardness was 2HRA higher and Vickers hardness was 28.38 Kgf/mm2 higher. The Rockwell hardness of cladding material 3BMo was 1.4HRA higher than that of 3B and the Vickers hardness was 17.67Kgf/mm2 higher than that of 3B. The results of three-point bending method indicated that the bending strengths of the cladding materials endured compressive stress and tensile stress respectively were improved after B was added, however, the bending strength reduced with the content of B increasing. The adding of Mo in the cladding could heighten the bending strength markedly.The wear resistance of the steel bond hard alloy cladding materials was studied by dry friction method and erosion wear method. The results indicated that the wear resistance of cladding material 3B, 4B, 5B and 3BMo was improved reasonably compared with the cladding material M without B and Mo. The corrosion resistance of the steel bond hard alloy cladding material was investigated and from the results of that, the corrosion resistance of the cladding materials was better than Q235 steel.The phase composition of the steel bond hard alloy claddings and the distribution of the hard phase and binder phase were studied. The interface character between hard phase and binder phase and the interface character between the cladding and the steel substrate were both investigated. The compartmentalization of the diffuse interface layer between steel and cladding material was advanced. The formation mechanism of the interface layer was investigated by the line scan analysis and the micro-hardness testing on the interface of cladding and steel. There were new phase Fe2B and Mo2FeB2 produced after B and Mo added. A metallurgical inlaying structure without cavity or gap formed between the cladding and the steel substrate because of B. The operational life of cladded hardware was much longer than that of uncladded hardware.The steel bond hard alloy cladding material was applied on the surfaces of the facile abrasion and erodible mechanical accessories, and some cladding hardwares were fabricated successfully. The working condition of steel bond hard alloy cladding hardwares under practical working condition was studied.
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