In this work,various backbone binders were used in wax-based binder system to formulate zirconia parts by ceramic injection molding (CIM).The effect of different backbone binders on the molding,debinding,and sintering...In this work,various backbone binders were used in wax-based binder system to formulate zirconia parts by ceramic injection molding (CIM).The effect of different backbone binders on the molding,debinding,and sintering behaviors was investigated.After blending process,the feedstock using multi-polymer components exhibited more homogeneous structure compared with that using the mono-polymer ones due to the synergistic effect of multi-polymers.During solvent debinding,some defects such as 'slumping' and 'peeling' appeared in the parts containing ethylene-vinyl acetate copolymer (EVA),but they were not found in the parts with other thermal polymers.Also,as for the parts after sintering,the one using low density polyethylene (LDPE) and high density polyethylene (HDPE) as backbone binders presented a more uniform microstructure with finer zirconia grains among all the investigated compositions,and thus obtained the highest flexural strength (～949 MPa) and relative density (～98.9％).展开更多
The influence of four kinds of binders consisting of paraffin wax （PW）, random-polypropylene （RPP）, high-density polyethylene （HDPE）, and stearic acid （SA） on the theological behavior of injection-molded SiC f...The influence of four kinds of binders consisting of paraffin wax （PW）, random-polypropylene （RPP）, high-density polyethylene （HDPE）, and stearic acid （SA） on the theological behavior of injection-molded SiC feedstocks was investigated over a temperature range of 150℃ to 180℃ and a shear rate range of 4 s^-1 to 1259 s^^-1. The results showed that all the feedstocks exhibited pseudoplastic flow behavior. The wax-based binder of multipolymer components （PW-RPP-HDPE） exhibited better comprehensive rheological properties compared with the binder of monopolymer components （PW-RPP or PW-HDPE）. The addition of 5wt% SA to the binder could reduce the viscosity of the feedstock but enhance the rheological stability by improving the wettability between the binder and the SiC powder. The binder of 65wt% PW ＋ 15wt% HDPE ＋ 15wt% RPP ＋ 5wt% SA was found to be a better binder for microsized SiC injection molding.展开更多
The thermal degradation behaviors of AlN green specimens were studied by thermogravimetry analysis during the ceramic powder injection molding debinding process. The optimum binder composition and the debinding cycle ...The thermal degradation behaviors of AlN green specimens were studied by thermogravimetry analysis during the ceramic powder injection molding debinding process. The optimum binder composition and the debinding cycle were demonstrated by observing the TGA and DTA plots of AlN green specimens and analyzing the microstructure at different temperatures. By adding HDPE into the PW EVA binder used in powder injection molding AlN can effectively reduce the mass lose rate in debinding process and improve the shape retention ability. At last, aluminum nitride ceramic with high room temperature thermal conductivity of 162.5?W·m -1 ·K -1 was produced. [展开更多
An improved wax-based binder was developed for the powder injection molding (PIM) of WC-TiC-Co cemented carbides. The critical powder loading and the rheologic behavior of the feedstock were determined. It was found t...An improved wax-based binder was developed for the powder injection molding (PIM) of WC-TiC-Co cemented carbides. The critical powder loading and the rheologic behavior of the feedstock were determined. It was found that the critical powder loading could achieve up to 62.5% (volume fraction) and the feedstock exhibited a pseudo-plastic flow behavior. The injection molding, debinding and sintering processes were studied. The dimension deviation of the sintered samples could be controlled in the range of ±0.2% with the optimized processing parameters and the mechanical properties were better than or equivalent to those of the same alloy made by conventional press-sintering process.展开更多
An improved wax-based binder was developed for the powder injection molding(PIM) of WC-TiC-Co cemented carbides. The critical powder loading and the rheologic behavior of thefeedstock were determined. It was found tha...An improved wax-based binder was developed for the powder injection molding(PIM) of WC-TiC-Co cemented carbides. The critical powder loading and the rheologic behavior of thefeedstock were determined. It was found that the critical powder loading could achieve up to 62.5percent (volume fraction) and the feedstock exhibited a pseudo-plastic flow behavior. The injectionmolding, debinding and sintering processes were studied. The dimension deviation of the sinteredsamples could be controlled in the range of + -0.2 percent with the optimized processing parametersand the mechanical properties were better than or equivalent to those of the same alloy made byconventional press-sintering process.展开更多
基金This work was financially supported by National Natural Science Foundation of China
文摘In this work,various backbone binders were used in wax-based binder system to formulate zirconia parts by ceramic injection molding (CIM).The effect of different backbone binders on the molding,debinding,and sintering behaviors was investigated.After blending process,the feedstock using multi-polymer components exhibited more homogeneous structure compared with that using the mono-polymer ones due to the synergistic effect of multi-polymers.During solvent debinding,some defects such as 'slumping' and 'peeling' appeared in the parts containing ethylene-vinyl acetate copolymer (EVA),but they were not found in the parts with other thermal polymers.Also,as for the parts after sintering,the one using low density polyethylene (LDPE) and high density polyethylene (HDPE) as backbone binders presented a more uniform microstructure with finer zirconia grains among all the investigated compositions,and thus obtained the highest flexural strength (～949 MPa) and relative density (～98.9％).
基金the National Natural Science Foundation of China(No.50274014)
文摘The influence of four kinds of binders consisting of paraffin wax （PW）, random-polypropylene （RPP）, high-density polyethylene （HDPE）, and stearic acid （SA） on the theological behavior of injection-molded SiC feedstocks was investigated over a temperature range of 150℃ to 180℃ and a shear rate range of 4 s^-1 to 1259 s^^-1. The results showed that all the feedstocks exhibited pseudoplastic flow behavior. The wax-based binder of multipolymer components （PW-RPP-HDPE） exhibited better comprehensive rheological properties compared with the binder of monopolymer components （PW-RPP or PW-HDPE）. The addition of 5wt% SA to the binder could reduce the viscosity of the feedstock but enhance the rheological stability by improving the wettability between the binder and the SiC powder. The binder of 65wt% PW ＋ 15wt% HDPE ＋ 15wt% RPP ＋ 5wt% SA was found to be a better binder for microsized SiC injection molding.
文摘The thermal degradation behaviors of AlN green specimens were studied by thermogravimetry analysis during the ceramic powder injection molding debinding process. The optimum binder composition and the debinding cycle were demonstrated by observing the TGA and DTA plots of AlN green specimens and analyzing the microstructure at different temperatures. By adding HDPE into the PW EVA binder used in powder injection molding AlN can effectively reduce the mass lose rate in debinding process and improve the shape retention ability. At last, aluminum nitride ceramic with high room temperature thermal conductivity of 162.5?W·m -1 ·K -1 was produced. [
文摘An improved wax-based binder was developed for the powder injection molding (PIM) of WC-TiC-Co cemented carbides. The critical powder loading and the rheologic behavior of the feedstock were determined. It was found that the critical powder loading could achieve up to 62.5% (volume fraction) and the feedstock exhibited a pseudo-plastic flow behavior. The injection molding, debinding and sintering processes were studied. The dimension deviation of the sintered samples could be controlled in the range of ±0.2% with the optimized processing parameters and the mechanical properties were better than or equivalent to those of the same alloy made by conventional press-sintering process.
基金This work was financially supported by the National Natural Science Foundation of China (No.50025412, 50274014), National 863 Program (No.2001AA337050) and National 973 Program (No.TG200067203)
文摘An improved wax-based binder was developed for the powder injection molding(PIM) of WC-TiC-Co cemented carbides. The critical powder loading and the rheologic behavior of thefeedstock were determined. It was found that the critical powder loading could achieve up to 62.5percent (volume fraction) and the feedstock exhibited a pseudo-plastic flow behavior. The injectionmolding, debinding and sintering processes were studied. The dimension deviation of the sinteredsamples could be controlled in the range of + -0.2 percent with the optimized processing parametersand the mechanical properties were better than or equivalent to those of the same alloy made byconventional press-sintering process.
