Rheological properties of alumina injection feedstocks

Bipolar plate is one of the key parts in the fuel cell technology with the advantages of a higher electrical conductivity and mechanical properties are high. Injection molding is one of the manufacturing method that being used in the manufacture of bipolar plates. The critical powder loading and rheological properties of the feedstock are an important factor in the process of injection molding in the manufacturing process of bipolar plate. The critical powder loading feedstocks with a mixture of polypropylene and graphite have been conducted with the torque method test. The appropriate critical powder loading the using a graphite filler material was produced with the composition of 75 % the weight of an optimum load and 25 % weight of polypropylene. The rheological studies have also been carried out using capillary test for determining critical loading powder by increasing the viscosity of the feedstock. The test results showed that the rheological properties of the feedstock with optimum powder loading to exhibit pseudoplastic properties are suitable for injection molding process with the n less than one.Keywords: injection molding, polymer composite, bipolar plate, fuel cell Abstrak Plat dwikutub adalah salah satu bahagian utama pada teknologi sel bahanapi dengan kelebihan sifat kekonduksian elektrik dan mekanik yang tinggi. Pengacuan suntikan adalah salah satu kaedah pembuatan yang digunakan dalam pembuatan plat dwikutub. Pembebanan serbuk genting dan sifat reologi bahan suapan adalah faktor penting dalam proses pengacuan suntikan semasa proses pembuatan plat dwikutub. Pembebanan serbuk genting bahan suapan dengan campuran polipropilina dan grafit telah pun dijalankan dengan kaedah ujian nilai tork. Pembebanan serbuk genting yang sesuai menggunakan bahan suapan grafit telah dihasilkan dengan komposisi 75 % berat yang merupakan beban optimum dan 25 % berat polipropilena. Kajian reologi juga telah dijalankan menggunakan ujian rerambut bagi menentukan beban serbuk genting dengan peningkatan nilai kelikatan bahan suapan. Keputusan ujian sifat reologi didapati bahawa bahan suapan dengan beban serbuk optimal mempamerkan sifat pseudoplastik yang sesuai bagi proses pengacuanan suntikan dengan nilai n kurang daripada 1.Kata kunci: pengacuan suntikan, komposit polimer, plat dwikutub, sel bahanapi ISSN -2506 Iswandi et al: CRITICAL POWDER LOADING AND RHEOLOGICAL PROPERTIES OF POLYPROPYLENE/GRAPHITE COMPOSITE FEEDSTOCK FOR BIPOLAR PLATE APPLICATION 688Introduction Conductive polymer composite (CPC) materials generally comprise a mixture of polymers and conductive fillers, such as carbon-based and metallic fillers. Conductive materials contribute to the improvement of electrical and mechanical properties (e.g., critical load) of a material, particularly for carbon-based materials, such as graphite (G), carbon black (CB), carbon nanotubes, and carbon fiber (CF) [1 -3]. One of the applications of CPC is the bipolar plate, which requires high electrical conductivity for electron mobility. The properties of CPC materi...

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“…% of the filler powder. These results are similar to those of ceramic-based materials and metals reported in [13] at 80.5 wt. % of filler.…”

Section: Resultssupporting

confidence: 90%

Critical Powder Loading and Rheological Properties of Polypropylene/Graphite Composite Feedstock for Bipolar Plate Application

Iswandi

Sahari

Sulong³

et al. 2016

MJAS

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“…It is suitable for technical ceramic, electronic and medical products, etc. CIM alumina exhibits properties close to pressed and sintered samples (Hwang & Hsieh, 2005;Hausnerova et al, 2011;Krauss et al, 2005). The most common material that is being used for feedstock preparation is Al 2 O 3 powder with 99.7% purity (Wei et al, 2000).…”

Section: Alumina For Cimmentioning

confidence: 96%

Ceramic Injection Molding

Stanimirovic¹,

Stanimirovic²

2012

Some Critical Issues for Injection Molding

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“…However, when dealing with holes produced by inserts (core), this becomes a main issue [8], mainly because of the cracks, voids and welding lines. Welding lines in injection molding usually occur because of the separation of the material flow, enforced by some obstruction and its posterior junction [18][19][20][21]. These welding lines are potentialized by the low part of organic vehicle in the feedstock.…”

Section: Este Trabalho Apresenta Um Estudo Para Avaliar O Processo Dementioning

confidence: 99%

Welding lines formation in holes obtained by low pressure injection molding of ceramic parts

2018

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This work presents a study to evaluate the process of producing internal holes in ceramic disks produced by low pressure injection molding (LPIM) process. Two process conditions defined as pre-injection and post-injection were used to test the proposition. In the first one the pin cores that produce the holes were positioned in the cavity before the injection of the feedstock; and in the second one, the pin cores were positioned in the cavity, just after the feeding phase of the injection mold. An experimental injection mold designed and manufactured to test both processes was developed to produce ceramic disk with Ø 50 x 2 mm with four holes of Ø 5 mm, equally and radially distributed through the disk. The feedstock was composed of 86 wt% alumina (Al 2 O 3 ) and 14 wt% organic vehicle based on paraffin wax. Heating and cooling systems controlled by a data acquisition system were included in the mold. The results showed that there were no welding lines with the post-injection process, proving to be an option for creating holes in the ceramic parts produced by LPIM. It was observed that best results were obtained at 58 °C mold temperature. The pins extraction temperature was about 45 °C, and the injection pressure was 170 kPa.

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Rheological properties of alumina injection feedstocks

Cited by 36 publications

References 5 publications

Critical Powder Loading and Rheological Properties of Polypropylene/Graphite Composite Feedstock for Bipolar Plate Application

Critical Powder Loading and Rheological Properties of Polypropylene/Graphite Composite Feedstock for Bipolar Plate Application

Ceramic Injection Molding

Welding lines formation in holes obtained by low pressure injection molding of ceramic parts

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