The effect of heating rates during vacuum debinding on the microstructure and mechanical properties of alumina ceramics are discussed in this paper.The threedimensional(3D)-printed alumina ceramics examined in this st...The effect of heating rates during vacuum debinding on the microstructure and mechanical properties of alumina ceramics are discussed in this paper.The threedimensional(3D)-printed alumina ceramics examined in this study were found to have a layered structure,and interlayer spacing increased as the heating rate increased The pore diameter,shrinkage,flexural strength and hardness were found to decrease as the heating rate increased due to weak interfacial bonding between alumina particles Shrinkage was found to be much larger along the Z direction than along the X or Y directions due to the layer-bylayer forming mode during 3D printing.0.5°C·min-1is considered the optimum heating rate,yielding ceramics with interlayer spacing of 0.65 lm,shrinkage of 2.6%2.3%and 4.0%along the X,Y and Z directions,respectively,flexural strength of 27.5 MPa,hardness of29.8 GPa,Vickers hardness of HV 266.5,pore diameter of356.8 nm,bulk density of 2.5 g·cm-3,and open porosity of38.4%.The debinding procedure used in this study could be used to produce a high-quality ceramic which can be used for fabricating alumina ceramic cores.展开更多
The thermal debinding behavior of stainless steel foam precursor in vacuum was studied and compared with that in hydrogen.The formation cause of pore channel was analyzed.The experiment results show that the binder re...The thermal debinding behavior of stainless steel foam precursor in vacuum was studied and compared with that in hydrogen.The formation cause of pore channel was analyzed.The experiment results show that the binder removal rate in vacuum is higher than that in hydrogen.In vacuum,the organic compounds can be removed effectively without change of pore size and the pore morphology for the sample.After pre-sintering,some sintering necks form and the sample has certain intensity.The initial surface pore forms with the temperature increasing at first,and then the internal melting binder is aspirated to form initial pore because of the capillary force and the metal powders re-arrange with the migration of binder at the same time.展开更多
During thermal debinding in ceramic injection molding, the inhomogeneity of green body is a key origin of cracks. In this study, the impact of low molecular weight binders on the homogeneity of the green body was inve...During thermal debinding in ceramic injection molding, the inhomogeneity of green body is a key origin of cracks. In this study, the impact of low molecular weight binders on the homogeneity of the green body was investigated. Incidence of cracks during thermal debinding indicated that the volume ratio of wax to stearic acid should be out of high viscosity and incompletely wetting region. In these two formulation regions, typical inhomogeneous microstructures were observed. By mercury intrusion method, it was shown that pore size distribution of the debinded compacts was determined by thermal degradation of low molecular weight binders. A particle-rich region model was established to predict the nucleation of cracks caused by solid loading fluctuation. The criterion of cracks nucleation was that local capillary force from solid loading fluctuation was larger than the suction force from the surroundings.展开更多
Binder system is critical to the success of metal injection molding(MIM). A novel PEG based binder for MIM was developed, which was made of high density polyethylene (HDPE), polyethylene glycol (PEG), polymer W, stear...Binder system is critical to the success of metal injection molding(MIM). A novel PEG based binder for MIM was developed, which was made of high density polyethylene (HDPE), polyethylene glycol (PEG), polymer W, stearic acid(SA) and dioctyl phthalate (DOP). The components of binder have interactions with each other, so the binder have good compatibility. The thermal decomposition process of binder exhibits three stages during debinding. The binder could be debound by pyrolysis or solvent, and could easily be removed in a short time in ethanol without defects and evironmental concern. A lot of interconnected pores formed after solvent debinding, which is helpful to the escape of pyrolysis gases during subsequent thermal debinding or presintering. [展开更多
The removal of the binder from the powder compacts (debinding) can be a slow step and a source of problems. To improve the debinding process of powder injection molding operation, it’s necessary to understand the the...The removal of the binder from the powder compacts (debinding) can be a slow step and a source of problems. To improve the debinding process of powder injection molding operation, it’s necessary to understand the thermal and mechanical properties of powder injection molding feedstocks and to find the major causes responsible for molding difficulties and compacts shape retention during debinding process. The effects of thermo mechanical properties of the PIM feedstock on the compacts shape retention during debinding process were discussed and explained from practical point of view. The results indicate that the heat of fusion affects the cooling time. The binder component with high heat of fusion and high decomposed temperature is more effective as the second binder component for the compact to retain its shape during debinding.展开更多
Micro powder injection molding （μPIM） was investigated for possible mass production of micro-components at rela- tively low cost. However, scaling down to such a level produces challenges in injection molding and d...Micro powder injection molding （μPIM） was investigated for possible mass production of micro-components at rela- tively low cost. However, scaling down to such a level produces challenges in injection molding and debinding. Micro gears were fabricated by μPIM from in-house feedstock. The effect of injection speed and injection pressure on the replication of the micro gear cavity was investigated. Solvent debinding and thermal debinding processes were discussed. The results show that micro gears can be successfully fabricated under the injection pressure of 70 MPa and the 60% injection speed. Either too low or too high injection speed can cause incomplete filling of micro gears. The same is the case with too low injection pressure. Too high injection pressure can bring cracks. Solvent debinding of micro gears was performed in a mixture of petroleum ether and ethanol. Subsequently, micro gears were successfully debound by a multistep heating schedule.展开更多
The thermal debinding dynamics of newly developed binders for cemented carbides extrusion molding was studied. It is shown that the thermal debinding processes can be divided into two stages: low temperature region, i...The thermal debinding dynamics of newly developed binders for cemented carbides extrusion molding was studied. It is shown that the thermal debinding processes can be divided into two stages: low temperature region, in which the low molecular mass components (LMMCs) are removed; and high temperature region, in which the polymer components are removed. The rate of thermal debinding is controlled by diffusion mechanism. The thermal debinding activation energies were solved out by differential method and integral method. The results show that the addition of other components acted as a catalyzer can effectively decrease the activation energy of thermal debinding processes.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
To successfully employ powder injection molding (PIM) as a manufacturing technique, the function of the component, design of the part, material and process should be optimized for overall processing ability of the PIM...To successfully employ powder injection molding (PIM) as a manufacturing technique, the function of the component, design of the part, material and process should be optimized for overall processing ability of the PIM process. A comparison between the requirements of flowability and moldability and the compacts shape retention has been made in this work. There is often a contradiction between the requirements of flowability and the compacts shape retention. Many works have been done to attain good molding conditions. However, they fail to take into account the effect of some factors that satisfies good molding conditions on the compacts shape retention during debinding. This paper studies the effect of the powder-binder mixture characteristics and the molding conditions on the flowability and moldability and the shape retention of PIM compacts during debinding process so as to attain the benefits of each.展开更多
Additive manufacturing(AM)has become a versatile and diverse technology that has a significant impact on manufacturing processes.Therefore,ceramic materials have been developed rapidly for use in AM processes.Vat phot...Additive manufacturing(AM)has become a versatile and diverse technology that has a significant impact on manufacturing processes.Therefore,ceramic materials have been developed rapidly for use in AM processes.Vat photopolymerization(VPP)is an AM method that enables the production of dense ceramic components with increased dimensional accuracy.In particular,it facilitates the fabrication of small and intricately shaped parts.This review summarizes the research advancements in ceramics prepared via VPP.Special attention is paid to the current status of relevant areas,such as slurry preparation and process optimization,as well as the form-ing mechanisms,debinding,sintering,performance characterization,and use of VPP-based ceramics.Moreover,earlier studies performed by our research group on numerous VPP-based ceramic aspects are considered.In ad-dition,a concise overview of the differences in forming principles,mechanical performance,advantages,and disadvantages between VPP-based ceramics and conventional colloidal-forming ceramics is presented.Finally,the challenges and prospects of VPP-based ceramics are discussed.展开更多
The solvent debinding of water soluble binder in powder injection moulding (MIM) was investigated systematically, including the effects of solvent types, temperature and the thickness of green parts on the solvent deb...The solvent debinding of water soluble binder in powder injection moulding (MIM) was investigated systematically, including the effects of solvent types, temperature and the thickness of green parts on the solvent debinding rate. After studying the debinding of a green part with a thickness of 4.26 mm, it was found that, the debinding rate of polyethylene glycol(PEG) in water and alcohol was high initially, and then decreased; however, it would increase with temperature increasing. At room temperature, the dissolution rate of PEG in water was higher than that in alcohol, but the latter would be much faster with temperature increasing because the debinding activation energy in alcohol was 51.44 kJ·mol -1 ·K -1 , much higher than 24.23 kJ·mol -1 ·K -1 in water. With a green part thickness larger than 4.26 mm, the debinding was controlled by diffusion; but with that smaller than 2.36 mm, the debinding was controlled by both dissolution and diffusion.展开更多
An improved wax-based binder was developed for powder injection molding of pure titanium. A critical powder loading of 69 vol.% and a pseudo-plastic flow behavior were obtained by the feedstock based on the binder. Th...An improved wax-based binder was developed for powder injection molding of pure titanium. A critical powder loading of 69 vol.% and a pseudo-plastic flow behavior were obtained by the feedstock based on the binder. The injection molding, debinding, and sintering process were studied. An ideal control of carbon and oxygen contents was achieved by thermal debinding in vacuum atmosphere （10^-3 Pa）. The mechanical properties of as-sintered specimens were less than those of titanium made by the conventional press-sintering process. Good shape retention and ±0.04 mm dimension deviation were achieved.展开更多
High-nitrogen nickel-free stainless steels were fabricated by the metal injection molding technique using high nitrogen alloying powders and a mixture of three polymers as binders.Mixtures of metal powders and binders...High-nitrogen nickel-free stainless steels were fabricated by the metal injection molding technique using high nitrogen alloying powders and a mixture of three polymers as binders.Mixtures of metal powders and binders with various proportions were also investigated, and an optimum powder loading capacity was determined as 64vol%.Intact injection molded compacts were successfully obtained by regulating the processing parameters.The debinding process for molded compacts was optimized with a combination of thermo-gravimetric analysis and differential scanning calorimetry analysis.An optimum relative density and nitrogen content of the specimens are obtained at 1360℃,which are 97.8%and 0.79wt%,respectively.展开更多
DC plasma is a very promising technology for processing different materials, and is becoming especially interesting when low environmental impact and high-performance treatments are needed. Some of the intrinsic chara...DC plasma is a very promising technology for processing different materials, and is becoming especially interesting when low environmental impact and high-performance treatments are needed. Some of the intrinsic characteristics of DC plasma technology, which make it suitable for powder metallurgy （PM） and powder injection molding （PIM） parts production, are low- pressure processing and plasma environment high reactivity. Moreover it can be considered as a highly competitive green technology. In this work, an overview of some of the important DC plasma techniques applied to PM and PIM parts processing is presented. Emphasis is given to the descriptions of the main characteristics and the technique potentials of plasma-assisted nitriding, plasma-assisted thermal debinding, plasma-assisted sintering, and simultaneously plasma-assisted sintering and surface alloying. The aspects presented and discussed in this paper indicate that DC plasma processes are promising and competitive techniques for PM and PIM parts processing.展开更多
A novel binder system for hardmetal powder extrusion moulding (PEM) process has been developed. The binder system comprises a major fraction of a mixture of low molecular weight components (LMWCs) and a minor fraction...A novel binder system for hardmetal powder extrusion moulding (PEM) process has been developed. The binder system comprises a major fraction of a mixture of low molecular weight components (LMWCs) and a minor fraction of very finely dispersed polymer. The feedstocks are mixed as a thick slurry at a suitable temperature and are rapidly homogenized by stirring at an adequate shear force. The binders are removed by thermal debinding. The thermal debinding mechanism has been investigated by thermogravimetry (TG) and differential thermogravimetry (DTG). At the first stage of debinding, the LMWCs are removed. These open up pore channels which allows much faster removal of the remaining polymer component during the subsequent stage. The microstructures of the moulded green parts were observed by scanning electron microscopy (SEM). The debound samples were sintered at different temperatures, and the sintered samples properties were measured.展开更多
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
基金financially supported by the National Key Research and Development Program of China(No.2018YFB1106600)the National Natural Science Foundation of China(No.51672217)。
文摘The effect of heating rates during vacuum debinding on the microstructure and mechanical properties of alumina ceramics are discussed in this paper.The threedimensional(3D)-printed alumina ceramics examined in this study were found to have a layered structure,and interlayer spacing increased as the heating rate increased The pore diameter,shrinkage,flexural strength and hardness were found to decrease as the heating rate increased due to weak interfacial bonding between alumina particles Shrinkage was found to be much larger along the Z direction than along the X or Y directions due to the layer-bylayer forming mode during 3D printing.0.5°C·min-1is considered the optimum heating rate,yielding ceramics with interlayer spacing of 0.65 lm,shrinkage of 2.6%2.3%and 4.0%along the X,Y and Z directions,respectively,flexural strength of 27.5 MPa,hardness of29.8 GPa,Vickers hardness of HV 266.5,pore diameter of356.8 nm,bulk density of 2.5 g·cm-3,and open porosity of38.4%.The debinding procedure used in this study could be used to produce a high-quality ceramic which can be used for fabricating alumina ceramic cores.
基金Project(50974136)supported by the National Natural Science Foundation of ChinaProject(CX2009B037)supported by the Graduate Degree Thesis Innovation Foundation of Central South University,China
文摘The thermal debinding behavior of stainless steel foam precursor in vacuum was studied and compared with that in hydrogen.The formation cause of pore channel was analyzed.The experiment results show that the binder removal rate in vacuum is higher than that in hydrogen.In vacuum,the organic compounds can be removed effectively without change of pore size and the pore morphology for the sample.After pre-sintering,some sintering necks form and the sample has certain intensity.The initial surface pore forms with the temperature increasing at first,and then the internal melting binder is aspirated to form initial pore because of the capillary force and the metal powders re-arrange with the migration of binder at the same time.
基金supported by the National Nature Science Foundation of China (NSFC) under grantNo. 50572049 the National High Technology Researchand Development Program of China ("863 Program") un-der grant No. 2007AA03Z522.
文摘During thermal debinding in ceramic injection molding, the inhomogeneity of green body is a key origin of cracks. In this study, the impact of low molecular weight binders on the homogeneity of the green body was investigated. Incidence of cracks during thermal debinding indicated that the volume ratio of wax to stearic acid should be out of high viscosity and incompletely wetting region. In these two formulation regions, typical inhomogeneous microstructures were observed. By mercury intrusion method, it was shown that pore size distribution of the debinded compacts was determined by thermal degradation of low molecular weight binders. A particle-rich region model was established to predict the nucleation of cracks caused by solid loading fluctuation. The criterion of cracks nucleation was that local capillary force from solid loading fluctuation was larger than the suction force from the surroundings.
文摘Binder system is critical to the success of metal injection molding(MIM). A novel PEG based binder for MIM was developed, which was made of high density polyethylene (HDPE), polyethylene glycol (PEG), polymer W, stearic acid(SA) and dioctyl phthalate (DOP). The components of binder have interactions with each other, so the binder have good compatibility. The thermal decomposition process of binder exhibits three stages during debinding. The binder could be debound by pyrolysis or solvent, and could easily be removed in a short time in ethanol without defects and evironmental concern. A lot of interconnected pores formed after solvent debinding, which is helpful to the escape of pyrolysis gases during subsequent thermal debinding or presintering. [
文摘The removal of the binder from the powder compacts (debinding) can be a slow step and a source of problems. To improve the debinding process of powder injection molding operation, it’s necessary to understand the thermal and mechanical properties of powder injection molding feedstocks and to find the major causes responsible for molding difficulties and compacts shape retention during debinding process. The effects of thermo mechanical properties of the PIM feedstock on the compacts shape retention during debinding process were discussed and explained from practical point of view. The results indicate that the heat of fusion affects the cooling time. The binder component with high heat of fusion and high decomposed temperature is more effective as the second binder component for the compact to retain its shape during debinding.
基金supported by the National Natural Science Foundation of China (No. 51172018)the Fok Ying Tong Education Foundation (No.122016)
文摘Micro powder injection molding （μPIM） was investigated for possible mass production of micro-components at rela- tively low cost. However, scaling down to such a level produces challenges in injection molding and debinding. Micro gears were fabricated by μPIM from in-house feedstock. The effect of injection speed and injection pressure on the replication of the micro gear cavity was investigated. Solvent debinding and thermal debinding processes were discussed. The results show that micro gears can be successfully fabricated under the injection pressure of 70 MPa and the 60% injection speed. Either too low or too high injection speed can cause incomplete filling of micro gears. The same is the case with too low injection pressure. Too high injection pressure can bring cracks. Solvent debinding of micro gears was performed in a mixture of petroleum ether and ethanol. Subsequently, micro gears were successfully debound by a multistep heating schedule.
文摘The thermal debinding dynamics of newly developed binders for cemented carbides extrusion molding was studied. It is shown that the thermal debinding processes can be divided into two stages: low temperature region, in which the low molecular mass components (LMMCs) are removed; and high temperature region, in which the polymer components are removed. The rate of thermal debinding is controlled by diffusion mechanism. The thermal debinding activation energies were solved out by differential method and integral method. The results show that the addition of other components acted as a catalyzer can effectively decrease the activation energy of thermal debinding processes.
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. [
基金This work was supported by the National Natural Science Foundation of Chira(project No.50044012)the Natural Science Foundation of Hunan Provience(project No.99JJYY20048).
文摘To successfully employ powder injection molding (PIM) as a manufacturing technique, the function of the component, design of the part, material and process should be optimized for overall processing ability of the PIM process. A comparison between the requirements of flowability and moldability and the compacts shape retention has been made in this work. There is often a contradiction between the requirements of flowability and the compacts shape retention. Many works have been done to attain good molding conditions. However, they fail to take into account the effect of some factors that satisfies good molding conditions on the compacts shape retention during debinding. This paper studies the effect of the powder-binder mixture characteristics and the molding conditions on the flowability and moldability and the shape retention of PIM compacts during debinding process so as to attain the benefits of each.
基金supported by Key-Area Research and Devel-opment Program of Guangdong Province of China(Grant No.2020B090923002)Guangdong Basic and Applied Basic Research Foun-dation of China(Grant No.2019B1515130005)+1 种基金Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program of China(Grant No.2017BT01C169)Foshan Science and Technology Innovation Team Project of China(Grant No.FS0AA-KJ919-4402-0023).
文摘Additive manufacturing(AM)has become a versatile and diverse technology that has a significant impact on manufacturing processes.Therefore,ceramic materials have been developed rapidly for use in AM processes.Vat photopolymerization(VPP)is an AM method that enables the production of dense ceramic components with increased dimensional accuracy.In particular,it facilitates the fabrication of small and intricately shaped parts.This review summarizes the research advancements in ceramics prepared via VPP.Special attention is paid to the current status of relevant areas,such as slurry preparation and process optimization,as well as the form-ing mechanisms,debinding,sintering,performance characterization,and use of VPP-based ceramics.Moreover,earlier studies performed by our research group on numerous VPP-based ceramic aspects are considered.In ad-dition,a concise overview of the differences in forming principles,mechanical performance,advantages,and disadvantages between VPP-based ceramics and conventional colloidal-forming ceramics is presented.Finally,the challenges and prospects of VPP-based ceramics are discussed.
文摘The solvent debinding of water soluble binder in powder injection moulding (MIM) was investigated systematically, including the effects of solvent types, temperature and the thickness of green parts on the solvent debinding rate. After studying the debinding of a green part with a thickness of 4.26 mm, it was found that, the debinding rate of polyethylene glycol(PEG) in water and alcohol was high initially, and then decreased; however, it would increase with temperature increasing. At room temperature, the dissolution rate of PEG in water was higher than that in alcohol, but the latter would be much faster with temperature increasing because the debinding activation energy in alcohol was 51.44 kJ·mol -1 ·K -1 , much higher than 24.23 kJ·mol -1 ·K -1 in water. With a green part thickness larger than 4.26 mm, the debinding was controlled by diffusion; but with that smaller than 2.36 mm, the debinding was controlled by both dissolution and diffusion.
文摘An improved wax-based binder was developed for powder injection molding of pure titanium. A critical powder loading of 69 vol.% and a pseudo-plastic flow behavior were obtained by the feedstock based on the binder. The injection molding, debinding, and sintering process were studied. An ideal control of carbon and oxygen contents was achieved by thermal debinding in vacuum atmosphere （10^-3 Pa）. The mechanical properties of as-sintered specimens were less than those of titanium made by the conventional press-sintering process. Good shape retention and ±0.04 mm dimension deviation were achieved.
基金supported by the National High-Tech Research and Development Program of China(No.2006AA03Z502)
文摘High-nitrogen nickel-free stainless steels were fabricated by the metal injection molding technique using high nitrogen alloying powders and a mixture of three polymers as binders.Mixtures of metal powders and binders with various proportions were also investigated, and an optimum powder loading capacity was determined as 64vol%.Intact injection molded compacts were successfully obtained by regulating the processing parameters.The debinding process for molded compacts was optimized with a combination of thermo-gravimetric analysis and differential scanning calorimetry analysis.An optimum relative density and nitrogen content of the specimens are obtained at 1360℃,which are 97.8%and 0.79wt%,respectively.
文摘DC plasma is a very promising technology for processing different materials, and is becoming especially interesting when low environmental impact and high-performance treatments are needed. Some of the intrinsic characteristics of DC plasma technology, which make it suitable for powder metallurgy （PM） and powder injection molding （PIM） parts production, are low- pressure processing and plasma environment high reactivity. Moreover it can be considered as a highly competitive green technology. In this work, an overview of some of the important DC plasma techniques applied to PM and PIM parts processing is presented. Emphasis is given to the descriptions of the main characteristics and the technique potentials of plasma-assisted nitriding, plasma-assisted thermal debinding, plasma-assisted sintering, and simultaneously plasma-assisted sintering and surface alloying. The aspects presented and discussed in this paper indicate that DC plasma processes are promising and competitive techniques for PM and PIM parts processing.
基金This research was supported by the National Natural Science Foundation of China (grant No.5964120, No.69971007). The financial support is gratefully acknowledged.
文摘A novel binder system for hardmetal powder extrusion moulding (PEM) process has been developed. The binder system comprises a major fraction of a mixture of low molecular weight components (LMWCs) and a minor fraction of very finely dispersed polymer. The feedstocks are mixed as a thick slurry at a suitable temperature and are rapidly homogenized by stirring at an adequate shear force. The binders are removed by thermal debinding. The thermal debinding mechanism has been investigated by thermogravimetry (TG) and differential thermogravimetry (DTG). At the first stage of debinding, the LMWCs are removed. These open up pore channels which allows much faster removal of the remaining polymer component during the subsequent stage. The microstructures of the moulded green parts were observed by scanning electron microscopy (SEM). The debound samples were sintered at different temperatures, and the sintered samples properties were measured.
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％).
