| Ni60alloy powder is one of the self-fluxing alloy powder, its powder particles arespherical and mainly contain the elements of Ni, Cr, B and Si. The B and Si easily form thesolid solution with Ni, and it will improve the total performance, in addition the melting pointwill be significantly reduced when B and Si add into the powder. Usually the powder is usedto prepare coating on the material in a manner of thermal spraying and the surfaceperformance will be improved, but the shortcomings of this technique are that the coating ispoor to the shock and load capacity. Its bond strength with matrix is low, and it is difficult tocoat evently when the shape of the materials is complex. Metal powder injection molding canform complex products at a time. Its design flexibility and adaptability to the material arebetter. Its products have a high dimensional accuracy and its density is distributed evently. Onthe ground of characteristics of the powder and advantages of metal powder injection molding,The Ni60feedstocks with concept of the feedstocks of metal powder injection molding werefirstly attempted to prepare in this paper, and the performance of Ni60feedstocks werestudied, the specific contents and conclusions were as follows:(1) The compatibility was good between PW and HDPE via the calculation of theirthermodynamic parameters and the TG-DSC analysis of binder. Then the binder of55%PW+40%HDPE+5%SA was prepared, and the Ni60feedstocks were perpared via thepowder and binder, the powder loadings were50%,55%and60%. The thermal propertieswas studied via the TG-DSC of the feedstocks and the holding temperature360℃and520℃of thermal debinding were determined.(2) The rheological properties of the Ni60feedstocks were studied used the capillaryrheometer. The results showed that the viscosity of Ni60feedstocks had the phenomenon ofshear-thinning. Its viscosity was improved when the powder loading was improved. TheNon-Newtonian index was reduced when the powder loading was improved, theNon-Newtonian index was improved when the temperature was improved. And the viscousflow activation energy was reduced when the powder loading and shear rate were improved. (3) The Ni60samples were molded used press forming, the way of debinding weresolvent debinding and thermal debinding. The removal rate of PW was improved whentemperature and time were improved, the removal rate of PW was reduced when powderloading was improved in the process of solvent debinding. The fracture surface of Ni60samples after thermal debinding showed that the binder had been removed completely.(4)1000℃of sintering temperature and2h of holding time were a good sinteringprocess via the experiments. In this process, the Ni60samples of60%powder loading hadshrinking of15.59%in the diameter direction,16.32%in the thickness direction. Its densitywas7.335g/cm3, and its hardness was543.4HB. Via the analysis of SEM-EDS and XRD,there were three areas of different color found on the sintering samples of Ni60. The gray areawas mainly-Niwhich contained elements of Ni, Fe, and C. The light gray area mainlycontained Ni2B and borides of Cr. The dark gray area mainly contained CrB, Cr5B3andborides of Cr.(5) The friction and wear experiments showed that the wear volume of the sinteringsamples was improved when load was improved. When holding time was improved, the wearvolume was reduced firstly, then it was improved. Experiments showed that the surface ofwear scar mainly contained the area of hardening block and the area of the removal ofhardening block. At last, the adhesive wear was the friction and wear type of the Ni60sintering samples was determined. |
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