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Chosen manufacture methods of Polymeric Graded Materials with electrical and magnetic properties gradation

Stabik J., Chomiak M., Dybowska A., Suchoń Ł., Mrowiec K.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 54, nr 2

218--226

EN

Purpose: The purpose of the paper is to present main results of Polymeric Graded Materials (PGMs) investigations realized in Silesian University of Technology, Division of Metallic and Polymeric Materials Processing. Methods of PGMs manufacture with electrical and magnetic properties gradation are mainly discussed. Design/methodology/approach: In short introduction general remarks on functionally graded materials (FGMs) and PGMs are presented. Next, methods used to prepare PGMs are presented together with physical basics determining composition, structure and properties gradation. Research methodology and chosen results showing PGMs structure and properties are also presented. Findings: Achieved results show that it is possible do design graded material structure and composition and to manufacture PGM that not precisely but in high extend meets designed requirements. The basic condition to accomplish this task is that physical basics of structure and composition gradient formation are known and relations between technological process parameters and ready material characteristics are properly applied. Research limitations/implications: Only chosen methods of PGMs manufacture are presented and only chosen PGMs characteristics are discussed. Practical implications: Presented technologies are widely used in industry to processing polymeric materials. Defined changes in parameters and properly designed composition will allow to utilize these technologies to PGMs manufacture. Ready parts with properties gradation may be applied in almost all industry branches. Few possible applications are presented in the text. Originality/value: New types of PGMs are described in the paper. Attention is paid mainly to materials with gradation of electrical and magnetic properties. The paper may be interesting for scientists involved in PGMs and for industry engineers looking for materials with electrical and magnetic properties gradation.

2

Wytwarzanie materiałów gradientowych technologiami przetwórstwa tworzyw polimerowych

Stabik J., Chomiak M., Dybowska A., Suchoń Ł.

Przetwórstwo Tworzyw

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2011

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[R.] 17, nr 3

221-225

PL

W artykule przedstawiono możliwości wykorzystania technologii przetwórstwa tworzyw polimerowych do wytwarzania materiałów gradientowych. Na wstępie krótko scharakteryzowano polimerowe materiały gradientowe a następnie przedstawiono wybrane technologie ich wytwarzania. Uwagę skupiono na takich technologiach jak odlewanie swobodne, odlewanie odśrodkowe, prasowanie, współwytłaczanie oraz polimeryzacja "in situ". Podano również przykłady wytworzonych materiałów i możliwości ich wykorzystania.

EN

The paper presents possibilities of application of plastics processing technologies to graded materials manufacturing. At the beginning Polymer Graded Materials (PGMs) are shortly characterized, next chosen technologies of their manufacture are presented. Attention is focused on such technologies as casting, centrifugal casting, pressing, co-extrusion and "in situ" polymerization. Examples of ready Polymer Gradient Materials and possibilities of their applications are also presented.

3

Magnetic properties of polymer matrix composites filled with ferrite powders

Stabik J., Chrobak A., Haneczok G., Dybowska A.

Archives of Materials Science and Engineering

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2011

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Vol. 48, nr 2

97-102

EN

The aim of this paper was to present magnetic properties research results of polymer matrix composites. The influence of the kind of fillers and amount of fillers on the magnetic properties of the composites was studied and is presented in this paper.

4

Polymer composites filled with powders as polymer graded materials

Stabik J., Dybowska A., Chomiak M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 1

153-161

EN

Purpose: The goal of this paper is to present general overview of research results on Polymeric Gradient Materials (PGMs) performed in Division of Metallic and Polymeric Materials Processing of Silesian University of Technology. Achievements in research on production technologies, compositions and properties are presented. Design/methodology/approach: Two basic technologies that were used for preparing polymeric gradient composites filled with powders are presented (centrifugal and gravity casting). Composites based on epoxy resin and filled with iron, ferrite, graphite, coal powders are characterized. Among other, the following properties were tested: surface resistivity, coefficient of friction, magnetic induction, filler particles distribution in polymeric matrix and others. Findings: Casting methods presented in this article can successfully be used to produce polymer composites characterized by gradual distribution of powder content and by this way by gradual distribution of properties. Results show that it is possible not only to achieve but also in some extend to control gradient of filler concentration. Especially in centrifugal casting is possible to influence gradient of filler concentration and in this way gradient of many properties. Research limitations/implications: The main problem in presented researches was to introduce higher quantities of filler. The side effect of high filler content was high viscosity. Filler particles were added to the epoxy matrix in range from 3vol.% to 50vol.% depending on filler properties, method of casting etc. Practical implications: Elaborated PGMs may be applied in many fields such as medicine, electronics, mining industry, machine building industry and many others. Originality/value: New type of polymeric gradient composites were achieved using centrifugal and gravity casting technique. Influence of casting parameters, concentration and type of filler on composites properties was researched.

5

Electrical properties of polymeric gradient materials based on epoxy resin filled with hard coal

Stabik J., Szczepanik M., Dybowska A., Suchoń Ł.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 38, nr 1

56-63

EN

Purpose: of this paper was to describe functionally the gradient polymeric materials and technology of the gradient production. The experimental part describes preparation of circular disc samples of polymeric gradient material by gravity casting method. Finally electrical surface resistance and surface resistivity was measured and analysed. Design/methodology/approach: Eight specimens were prepared using gravity casting method. Composites with epoxy resin as a matrix and with respectively 3, 6, 9 and 12%vol of two types of hard coal as a filler were cast. Surface resistivity was applied as a measure of electrical properties. The idea of the test was to define electrical resistivity in sequential layers with different content and type of conductive component (hard coal). First, specimen’s thickness was measured and electrical resistivity was tested. Next, outer layer was removed by grinding and electrical measurements performed. The procedure was repeated for all subsequent layers. In effect, dependence of surface resistivity on depth of the layer was determined. Findings: The experimental results demonstrated that addition of conductive filler (hard coal) to epoxy resin caused a change of surface resistivity of these materials. Hard coal together with epoxy resin formed gradient composite material with different filler content in subsequent layers. Research limitations/implications: Further investigations with higher hard coal content and/or with different matrix are needed. Originality/value: This paper is original because in the research programme electrical properties of new type of polymeric gradient composites were tested and presented in it.

6

Magnetic induction of polymer composites filled with ferrite powders

Stabik J., Dybowska A., Pluszyński J., Szczepanik M., Suchoń Ł.

Archives of Materials Science and Engineering

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2010

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Vol. 41, nr 1

13-20

EN

Purpose: The goal of this work was to determine influence of amount and type of ferrite fillers on magnetic induction of epoxy composites. Six mixtures that contain different amount of ferrite powder were prepared. Additionally an effect of type and amount of introduced ferrite powder on epoxy resin processing conditions and parameters was searched. Design/methodology/approach: In this research the method of preparing polymeric gradient composites was centrifugal casting. The experimental procedure focused on evaluating the magnetic induction of gradient composites. Magnetic induction of composites based on epoxy resin, which contain ferrite powders was measured using milliteslometer. Measurements were performed for three filler contents and for two types of filler. Findings: Centrifugal casting method allowed obtaining materials with different percentage of ferrite content in subsequent layers of cylindrical composites. Moreover it was observed that values of magnetic induction were higher for composite with barium ferrite than for composite with strontium ferrite but the difference was not too high. Research limitations/implications: The main problem of this work was about limitation of maximum level of fillers content. Adding more filler than 30%vol caused very rapid composite viscosity increase and made air removing and casting impossible. For that reason there were made composites with 10%vol., 20%vol. and 30%vol. of ferrite powders. Trials were performed with mixtures that contained up to 50%vol. of filler. Practical implications: Method applied in this research allowed to obtain materials that are characterized by gradient of magnetic properties. Such composites find applications in electrotechnical industry and in mechanical engineering. Originality/value: New polymeric gradient materials were developed using centrifugal casting technology. Magnetic properties of these composites were determined depending on distance from the surface of the test piece.

7

Viscosity measurements of epoxy resin filled with ferrite powders

Stabik J., Dybowska A., Szczepanik M., Suchoń Ł.

Archives of Materials Science and Engineering

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2009

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Vol. 38, nr 1

34-40

EN

Purpose: The goal of this work was to determine influence of fillers on viscosity, especially of six mixtures that contain different amount of ferrite powder. It was made in order to find out an effect of introduced ferrite powder on epoxy resin processing conditions and parameters. Additionally viscosity of pure epoxy resin was determined for reference purposes. The influence of temperature on composites viscosity was also examined. Design/methodology/approach: Viscosity of mixtures based on epoxy resin that contain ferrite powders and pure epoxy resin using Hoeppler viscometer was measured. Procedures of viscosity measurements were performed for three temperatures and for three filler contents. Findings: Higher temperature of measurement resulted in lower values of viscosity while higher quantity of ferrite powder increased viscosity of mixtures. There was no difference between results of viscosity that were obtained for barium ferrite and strontium ferrite. Research limitations/implications: The main problem of this work was limitations of research method. Mixtures before measurement had to be put to the vacuum venting in order to remove air bubbles that were introduced through mixing. Also an amount of powder introduced into the matrix was limited because for higher contents it was not possible to pour mixtures into glass pipe of measurement device. Practical implications: Applied method allowed to determine the influence of temperature, kind and quantity of filler on viscosity. Viscosity is the main factor defining processing parameters in many processing technologies. Originality/value: Results of viscosity for searched composites are not known up till now. Achieved results are planned in order to use them in future works of authors on polymeric magnetic composites.

8

Influence of graphite on electrical properties of polymeric composites

Szczepanik M., Stabik J., Łazarczyk M., Dybowska A.

Archives of Materials Science and Engineering

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2009

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Vol. 37, nr 1

37-44

EN

Purpose: of this work was to prepare polymeric composite materials with different contents of graphite and to search the influence of graphite on electrical properties of these materials. Design/methodology/approach : Five specimens were prepared using gravity casting method. Composites with epoxy resin as a matrix and with respectively 3, 6, 9 and 12%vol of graphite PV60/65 as a filler were cast. Surface resistivity was applied as a measure of electrical properties. The idea of the test was to define electrical resistivity in sequential layers with different content of conductive component (graphite). First, specimen's thickness was measured and electrical resistivity was tested. Next, outer layer was removed by grinding and electrical measurements performed. The procedure was repeated for all subsequent layers. In effect surface and volume resistivity dependence on depth of the layer was determined. Findings: The experimental results demonstrated that addition of conductive filler (graphite) to epoxy resin caused change of surface and volume resistivity of these materials. Research limitations/implications: Further investigations with higher carbon content and/or with different matrix are needed. Practical implications: Addition of 3-6%vol. of graphite to epoxy resin caused limited, almost linear, decrease of surface resistivity in depth direction of specimens. Higher content of filler (9-12%vol) in polymeric composite caused rapid, non-linear with layer depth, decrease of surface and volume resistivity. Originality/value: This paper is original because in the research programme gravitational casting was used to prepare polymeric composite materials with gradient of electrical properties.

9

Electrical and tribological properties of gradient epoxy-graphite composites

Stabik J., Dybowska A.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 27, nr 1

39-42

EN

Purpose: The goal of this work was to use gravity casting as a method to prepare composite material that is characterized by gradient of electrical and tribological properties. Furthermore electrical and tribological properties of composites filled with two different kinds of graphite were compared. Design/methodology/approach: In this research the method of preparing polymeric gradient composites was gravity casting. The experimental procedure focused on evaluating the electrical resistivity and coefficient of fraction (by the pin-on-disc method) of gradient composites. Findings: Gravity casting method allowed to obtain materials with different percentage of graphite content in subsequent layers of composite. Moreover it was observed that values of coefficient of friction were higher for composite with SV94 graphite than for composite with PV60/95. Research limitations/implications: The main problem for this work was to obtain continuous change of properties depending on the distance from surface. The particle's diameter distribution, shape and size of reinforcement were significant in manufacture of composites and influenced gradient of tested properties. Practical implications: Method applied in this research allowed to obtain materials that are characterized by gradient of electrical and tribological properties. Such composites find applications in electrical industry and in mechanical engineering. Originality/value: New polymeric gradient materials were developed using gravity casting technique. Electrical and tribological properties of these composites were determined depending on distance from the surface of the test piece.

10

Methods of preparing polymeric gradient composites

Stabik J., Dybowska A.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 25, nr 1

67-70

EN

Purpose: The goal of this work is to introduce basic methods of preparing polymeric gradient materials, which allow to join two different components to ensure the required properties and structure of the functionally gradient materials. Design/methodology/approach: In this paper few of methods of preparing functionally gradient polymeric materials are briefly described which were successful employed in many investigations performed during last few years. Findings: It was noticed that the knowledge about polymeric gradient materials is still developing what can allow to manufacture new products characterized by unique properties. Research limitations/implications: Most of methods presented in this paper are also used for conventional products, the difference between conventional products and products with gradient are quantity of components, shape and size of reinforcements, and properties of ready materials. Practical implications: Presented methods can be applied in preparing FGMs for future research programmes and also in industrial processes. Originality/value: Techniques are presented that can be useful in future scientific work concerning functionally gradient materials containing polymer materials.

11

Effect of WC concentration on structure and properties of the gradient tool materials

Dobrzański L. A., Kloc-Ptaszna A., Dybowska A., Matula G., Gordo E., Torralba J. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 20, nr 1-2

91-94

EN

Purpose: The goal of this work is to obtain the contemporary gradient materials based on the tungsten carbide reinforced high-speed steel using the conventional powder metallurgy method and increasing the high-steel hardness (80 HRA = 800 HV) by introducing the tungsten carbide as the reinforcing phase, with hardness exceeding 2200 HV. Design/methodology/approach: The materials were fabricated with the conventional powder metallurgy method consisting in compacting the powder in the closed die and finally sintering it. Forming methods were developed for powders of the HS6-5-2 high speed steel and WC, making it possible to obtain material with seven layers in the structure. Findings: It was found out basing on the microhardness tests that hardness of test pieces grows along with the sintering temperature and with WC content in the interface layers and in the high-speed steel ones. It was also observed that porosity decreases along with the WC concentration increase in these layers. It was found out, basing on the comparison of structures and properties of the compacted and sintered test pieces, that in structures of all examined test pieces in the sintered state fine carbides occurred distributed homogeneously in the high-speed steel layer. Research limitations/implications: It was noticed, that increase of the sintering temperature results in the uncontrolled growth and coagulation of the primary carbides and melting up to forming of eutectics in layers consisting of the high-speed steel. Practical implications: Material presented in this paper has layers consisting on one side from the mix of the high-speed steel and WC, and on the other side the high-speed steel, characteristic of the high ductility. Such material is tested for milling cutters. Originality/value: The layers were poured in such way that the surface layer consists of the mix of the high-speed steel and WC, and the middle one from the high-speed steel. The layers inside the material are mixes of the high-speed steel and WC in the relevant proportions.