Nano Powder in Fe Bimodal Powder Injection Molding Process
The effects of the nano powder on nano/micro bimodal powder injection molding process were investigated in this study.100 nm and 3 μm Fe powders were used and pre-mixed to prepare bimodal powders.The mixing ratios of nano powder were 25,50 and 75 vol.%.With those five different powders and a wax-based binder system,powder injection molding process was developed and optimized.The optimization process included the determination of solids loadings,optimal mixing process for feedstock homogeneity,conditions of debinding and sintering processes.For each step,the effects of nano powder were also analyzed.The results showed the large surface area of nano powder decreased the critical solids loading.However,it was compensated by the bimodal packing effect.As a result,relatively high critical values were observed in the bimodal powders.The feedstock homogeneity was evaluated by viscosity measurement method,and the feedstocks were mixed 6 times to obtain the maximum homogeneity.Nano powder enhanced the challenges in debinding.The narrow interparticle space and the large surface of the nano particles hindered the binder dissolving in a solvent.They also changed the binder decomposition temperature.The samples were sintered at 900 ℃ and various holding times,and the density and Vickers hardness were measured.The result indicated the optimal nano powder ratio for the highest density and hardness was 25 vol.%.
Bimodal powder Fe Feedstock Nano powder Powder injection molding
Oh Joo Won Lee Won Sik Park Seong Jin
Department of Mechanical Engineering,Pohang University of Science and Technology(POSTECH),77 Cheonga The Advanced Process and Materials R&D Group,Korea Institute of Industrial Technology(KITECH),156 Ga
国际会议
北京
英文
608-612
2018-09-16（万方平台首次上网日期，不代表论文的发表时间）