The properties of PW-EVA-HDPE binder with the addition of MW were studied. It shows that the addition of MW from 1% to 20%(mass fraction) causes an increase in the tensile strength and a decrease in shrinkage of the b...The properties of PW-EVA-HDPE binder with the addition of MW were studied. It shows that the addition of MW from 1% to 20%(mass fraction) causes an increase in the tensile strength and a decrease in shrinkage of the binder. After blending PW with MW, the crystallation behavior of wax base changes, which results in fine grain for the binder and more isotropic microstructure for the feedstock. The powder loading capacity increases and homogeneity of feedstock becomes better. The reason of the modification is also discussed.展开更多
Effects of the surfactant for improving the properties of MIM feedstock were investigated. Feedstocks were prepared by 17-4PH stainless steel(SS) powder and paraffin wax-based binder containing different contents of s...Effects of the surfactant for improving the properties of MIM feedstock were investigated. Feedstocks were prepared by 17-4PH stainless steel(SS) powder and paraffin wax-based binder containing different contents of stearic acid(SA) as the surfactant. The viscosity of the feedstock decreases significantly when the SA is added. Besides, the wetting angle of the binder against the 17-4PH SS powder decreases greatly and the critical solid loading increases with the adding of the SA. Fourier transformation infrared spectroscopy(FTIR) analysis was used to prove the interaction between the SA and the 17-4PH SS powder. Chemical bonding is found on the surface of 17-4PH SS powder after mixing and it helps a lot to enhance the interacting force between the binder and the powder. Then an adsorbing model was adopted to estimate the least content of the surfactant that formed a monolayer adsorption on the mono-sized spherical powder (with smooth surface). The least content of the surfactant is calculated to be 0.19%. Whereas, the experiments indicate that about 5% is the optimal value to improve the properties of the feedstock. The reason may come from two aspects: firstly, the powders used in current experiment are not all mono-sized spheres and the coarse surface of the powder has a great effect on the adsorptive capacity of the powder; secondly, multilayer adsorption is likely to occur on the powder surface, which will also increase the adsorptive capacity.展开更多
文摘The properties of PW-EVA-HDPE binder with the addition of MW were studied. It shows that the addition of MW from 1% to 20%(mass fraction) causes an increase in the tensile strength and a decrease in shrinkage of the binder. After blending PW with MW, the crystallation behavior of wax base changes, which results in fine grain for the binder and more isotropic microstructure for the feedstock. The powder loading capacity increases and homogeneity of feedstock becomes better. The reason of the modification is also discussed.
基金Project(200135) supported by Chinese National Excellent Dissertation FoundationProject(NECT-04-0754) supported by Program for New Century Excellent Talents in University of China
文摘Effects of the surfactant for improving the properties of MIM feedstock were investigated. Feedstocks were prepared by 17-4PH stainless steel(SS) powder and paraffin wax-based binder containing different contents of stearic acid(SA) as the surfactant. The viscosity of the feedstock decreases significantly when the SA is added. Besides, the wetting angle of the binder against the 17-4PH SS powder decreases greatly and the critical solid loading increases with the adding of the SA. Fourier transformation infrared spectroscopy(FTIR) analysis was used to prove the interaction between the SA and the 17-4PH SS powder. Chemical bonding is found on the surface of 17-4PH SS powder after mixing and it helps a lot to enhance the interacting force between the binder and the powder. Then an adsorbing model was adopted to estimate the least content of the surfactant that formed a monolayer adsorption on the mono-sized spherical powder (with smooth surface). The least content of the surfactant is calculated to be 0.19%. Whereas, the experiments indicate that about 5% is the optimal value to improve the properties of the feedstock. The reason may come from two aspects: firstly, the powders used in current experiment are not all mono-sized spheres and the coarse surface of the powder has a great effect on the adsorptive capacity of the powder; secondly, multilayer adsorption is likely to occur on the powder surface, which will also increase the adsorptive capacity.
