Removal of low molecular weight components during thermal debinding of powder compacts

Angermann, H.H; Yang, Fanghong; Biest, Omer Van der

doi:10.1007/bf01105066

Cited by 21 publications

(13 citation statements)

References 1 publication

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“…Thermal debinding allows binder removal by increasing the temperature. The polymer is decomposed into volatile species that diffuse through the [25,26]. Different gasses are applied to improve the decomposition by increasing the speed or preventing formation of residues.…”

Section: Debindingmentioning

confidence: 99%

Overview of powder injection molding

1996

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Powder injection molding is a near net-shape technique suitable for the production of moderate to large volumes of small complex components of a wide range of materials such as ceramics, metals and hard metals. It combines the plastics injection molding technique with the power sintering techniques to produce high density parts at close tolerances. The technology has been known for more than 40 years, but it is only for the last decade that it became a commercial reality. Thanks to recent economical and technological developments the business outlook is positive with parts being produced for a wide field of applications. Still, in order to become truly a great commercial success researchers and producers have to overcome numerous technical and economical challenges and increase the awareness among designers.

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Section: Debindingmentioning

confidence: 99%

Overview of powder injection molding

1996

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“…Therefore debinding has been studied to explore its kinetics of extracting the binder as fast as possible. [2][3][4][5] Previously, debinding cycles were based on ''trial and error'' until an adequate time-temperature cycle was achieved. With the use of a multicomponent binder system, achieving an economical and effective debinding cycle while maintaining the compact's shape can be quite difficult.…”

Section: Introductionmentioning

confidence: 99%

Master Decomposition Curve for Binders Used in Powder Injection Molding

Aggarwal

Park

Smid

et al. 2007

Metall Mater Trans A

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Thermal debinding is one of the crucial steps in powder injection processing. To systematically analyze and design the thermal debinding step, a master decomposition curve (MDC) has been formulated and constructed based on the intrinsic kinetics of polymer pyrolysis. The Kissinger method is used to estimate the activation energy from thermogravimetric studies. Overall thermal decomposition behavior has been synthesized from the MDCs of individual components of the binder system with good experimental agreement. Thus, process design changes can be calculated without additional experiment, because the MDC concept allows synthesis of new compositions. The input data were obtained from industrial debinding practice. In addition, the catalytic or high-conduction heat-transfer effect of metal powders has been investigated in terms of different powders. Sensitivity analysis is also done to identify the critical parameters in thermal decomposition of binders during debinding.

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“…This complex process, together with a high amount of powder surrounding the polymer (around 99 pct), may be the cause of the incomplete polymer release, even in a reducing atmosphere. Finally, the very small polymer amount itself may be too little to form the canals by which it can be released from the interior of the rigid body, according to the model proposed by Angermann et al [32] It has also been observed during thermal analysis of pure organic compounds that both are carbonized as the temperature rises, and this may prohibit their release to the surface of the sample and hence limit their removal with a gas flow. In this case, the amount of carbon left by the incomplete polymer release will help in promoting the sintering.…”

Section: B Thermal Analysismentioning

confidence: 95%

Starch Consolidation as a New Process for Manufacturing Powder Metallurgy High-Speed Steels

Romano

Velasco

Torralba

2007

Metall Mater Trans A

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The development of a new method called ''starch consolidation,'' suitable for the production of powder metallurgy (P/M) high-speed steel (HSS) components has been studied. Samples have been consolidated using 1.5, 3.5, and 5 vol pct starch and up to 60 vol pct powder. The high solid loading was achieved by stabilizing the repulsive forces with a small addition (0.01 wt pct) of a dispersant (polyacrylic acid) that resulted in accurate fluidity and consolidation of the prepared slurries. After shaping of the samples, the bending strength of the green bodies was evaluated. Debinding cycles were optimized by comparing carbon and oxygen content in argon, in N 2 -5H 2 , and in pure hydrogen. The three atmospheres showed no significant differences in carbon elimination. To determine the influence of H 2 in a nitrogen-rich atmosphere during sintering, tests were performed at 1230°C in a N 2 -5H 2 and in a nitrogen atmosphere. Pure nitrogen resulted in a microstructure formed by smaller carbides. Heat treatments were performed on the samples with the compositions that gave the best combination of properties. A hardness of 800 HV and a bending strength of 1475 MPa were obtained.

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Removal of low molecular weight components during thermal debinding of powder compacts

Cited by 21 publications

References 1 publication

Overview of powder injection molding

Overview of powder injection molding

Master Decomposition Curve for Binders Used in Powder Injection Molding

Starch Consolidation as a New Process for Manufacturing Powder Metallurgy High-Speed Steels

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