36

Vol.35,No.1(2013)36‐41

TribologyinIndustry

www.tribology.fink.rs

ExaminationofWearResistanceofPolymer–BasaltComposites

A.Todić

a,D.Čikaraa,V.Lazić

b,T.Todića,I.Čamagić

a,A.Skulić,D.Čikarac

a

UniversityofPriština,FacultyofTechnicalSciences,KnezaMilosa7,38220KosovskaMitrovica,Serbia.b

UniversituofKragujevac,FacultyofEngineering,SestreJanjić6,34000Kragujevac,Serbia.c

UniversityofBelgrade,FacultyofTechnologyandMetalurgy,Karnedžijeva4,11000Belgrade,Serbia.

Keywords:

WearBasaltCompositePolymers

ABSTRACT

Olivine basalt, as a natural material, has excellent physical and mechanicalproperties such as hardness, compressive strength,wear resistance, color andgloss.Ontheotherhanditisdifficultforprocessing,becauseofitshighvaluesofmechanicalproperties.Retentionofphysicalandmechanicalpropertiesofbasaltanditsformationisonlypossiblebymixingbasaltpowderwithpolymerswhichwouldenablethecompositematerialthatcanbe formedbythecastingprocessintocomplexshapes.Themechanicalpropertiesoftheobtainedcompositesandproductiontechnologiesare,toagreatextent,unknowninboth,localandforeignliterature.Researchersconductedandpresentedinthispapershowanoverviewof tribological behavior of the basaltic composite material and sometechnological parameters of the production process. Based on the obtainedresults,itcanbedeterminethebestratioofcomponentsinthecomposite.Thesedata are important for the development of new compositematerials based onbasalt,whichwillhavesignificantapplicationinthefuture.

©2013PublishedbyFacultyofEngineering

Correspondingauthor:

V.LazićUniversituofKragujevac,FacultyofEngineering,SestreJanjić6,34000Kragujevac,SerbiaE‐mail:vlazic@kg.ac.rs

1. INTRODUCTION

Research in thiswork is aimed to create anewcomposite material, which consists of basalt,polymersandadditives.The main goal of this research is to obtain abasalt‐polymer base composite that hasproperties of basalt (good strength, hardnessand toughness) and is also suitable for formingbycastingprocess that ispractically impossiblefor the pure basalt. The combination of thesetwo materials should allow the obtaining of anewmaterialthatwillkeepthecharacteristicsof

basalt (primarilyhighhardness, color, etc.) andpolymersthatallowitseasyforming.The long geological, mining and technologicalresearchtendstoshowthatthebasaltorecanbecost‐effectiveforproductionofvariousproductsofbasalt aggregates such as: basalt composites,basaltic glass, cast basalt, basalt fibers, and evenjewelrywhosevalueissimilartovaluesofjewelrymade of semi‐precious stones. These researchesincludeddefiningof theparameterof theprocessfor obtaining composites of basalt and polyesterresin (Polipol 357‐C, 383, Polipol, BRE‐325, etc.),bycastingmethods.

RESEARCH

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Theprocessparameterstobedeterminedare:thegranulometriccompo‐sitionofbasalticaggregates,type and amount of the resin and additives, ele‐mentsofcastingandpressingprocess,etc.2. PREPARATIONOFTHECOMPONENTSANDMOLDS

Basalt is very strength and hard alumo‐silicaterock,whichbelongtowildgroupofgranites.Forthepurposesofthisresearch,thebasaltistakenfrom the locality of „Vrelo”, situated on theslopesofKopaonikMountain in the South‐westofSerbia.From the mineralogical analyses of basaltsamples Vrelo locality, we can see that theserocksareverycompact.Porphyrystructurewithdistinctlymarkedfenocrystals,1‐3mmsize,waseasily noted. Rock mass is very fine‐grained,crypto crystalline and mat‐black colored.Mineral composition appears on two ways: inolivine fenocrystals that is predominating andpyroxene that is inferior. Physical andmechanical properties of the basalt from VrelolocalityaregiveninTable1.Table1.PhysicalandmechanicalpropertiesofbasaltfromVrelolocality.

Density(kg/m3) 2600– 2630Meltingpoint(°C) 1150– 1170Compressionstrength(drystate)(MPa) 240– 260Compressionstrength(hydrosaturatedstate)(MPa)

210– 225

Compressionstrength(afterfreezing)(MPa)

190– 195

Wearresistance(methodBohme)(cm3/50cm3)

4.1– 4.5

Wearresistance(methodLosAngeles)(%) 11.5– 12.0Rawbasaltgrainsizewas3to5mm.Thisbasaltaggregate was milled and micronized intungsten‐carbidevibratingmill.Millinglasted30minutes, and after that basalt powder wascentrifugallysiftedintothefollowinggranulations:

100μm

150+50μm

300+100μm

500+300μmi

1000+500μm.

Formakingthecomposites,polyesterresinBRE325 (manufacturerBOYTEK ‐Turkey)wasused

[3]. This is orthophthalic unsaturated polyesterresinwith lowreactivityandmediumviscosity.It is used for the construction of sanitaryelementsandfigurinesbycastingprocess.Aftercuring,ithashighelongation,nicecolorandverygood soaking of fillers. Manufacturer of thesepolyester resins declared characteristics showninTable2and3[3].

Table2.Physicalpropertiesofliquidresinat20°C.

Viscosity (cp) 700– 900Acidnumber(max.)(mgKOH/g) 30Styrene content (%mass) 32– 38Exothermic peak (°C) 130– 140Timeof gelation 1%Co (minutes) 5– 10Storagestability (months) 6Table3.Mechanicalandphysicalpropertiesofresininthefullymaturedstate.

Tensilestrength (MPa) 55Modulusofelasticity (MPa) 2800Elongation (%) 65Bendingstrenght (MPa) 110Flexuralmodulus(MPa) 3100Hardness(Barkola) 35Heat distortion temperature (°C) 55

As thecatalystand initiatorhighactiveMethyl‐ethyl‐ketone‐peroxidewasused. The catalyst isadded inanamountof2%of themassof resinused. As an accelerant we used Co (6%) at aconcentration between 0.2% and 0.6% of theamountofthepolyesterresin[456].Patternformaking molds are made of metal alloy instandardsizesforthistypeoftesting.Moulds are made of high tackiness silicone(poliysilosan). This is a two‐component siliconewherethefirstcomponentispuresiliconeandthesecond component is a hardener.Mixing siliconeandhardenerisperformedbymixingupto30sat23 °C, until color become homogenous. Moldsmakingisperformedbypressingofpatternintheformedmassandforfullcuringofmoldsaperiodofabout72hisrequired[78].Thissiliconemassisusedbecauseitdoesnotglueto polyester resin, and allows easy extraction oftestspecimensfromthemold.Thedisadvantageisthat the silicone molds, do not allow highpressures, because they will elastically deform.Therefore,itisnecessarytopouramixtureatlowpressurejustenoughthattheexcessofmaterialbeextrudedfromthemold[9].

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3. PREPARATIONOFTHECOMPOSITEMIXTURE

Thissiliconemassisusedbecauseitdoesnotgluetopolyester resin, that allowseasy extractionoftest specimens from themold.Thedisadvantageis that the silicone molds, do not allow highpressures, because they will elastically deform.Therefore,itisnecessarytocastamixtureatlowpressure just enough that the excess ofmaterialbeextrudedfromthemold[9].Testingsamplesaremadeofcompositeswiththedifferent ratios of basalt powder and polyesterresin,differentgranulationanddifferentcontentofaccelerators.SamplesdesignationswithvaluesoftheirmassesaregiveninTable4.Designationof samples consists of three ascendants (Fig. 1)where the first ascendant indicates the basaltgrain size, the second amount of basalt in themixture, and the third, the content of theacceleratorinthemixture.Basalt mixture made of these components areuniformly mixed to homogeni‐sation about 10min and then poured into the mold. Pouredmixture solidifies at room temperature and thecuring time is 30 to 50minutes, depending onthe percentage of basalt powder in it. Aftercuring samples, together with molds,

transferred into the furnace and heated to atemperature of 60 °C for 3 hours. In the nextstage, the samples will be removed from themoldandreheatedattemperatureof100°Cforone hour. Completion of the polymerizationprocess continues after removing the samplesfrom the furnace in thenext24hours. Samplesfor wear resistance testing are made by thismethod.Figure2showsoneofthetestsamples.In the Fig. 3 is given photos of the wearresistancetestingdevice.Table4.Samplesfortestingresistancewear

Samplesdesignation

Samplemass m0

(g)I3a 11.36I3b 10.29I4a 10.64I4b 10.93I5a 12.60I5b 11.50I6a 12.71I6b 11.87I8a 13.70I8b 13.57II6a 12.16II6b 12.96III6a 12.20III6b 12.64IV6a 12.37IV6b 12.54V6a 13.42V6b 13.52

Fig.1.Schematicpresentationofsamplesdesignation.

X Y Z

Basaltgrainsize

IIIIIIIVV

150+50 μm

100 μm

300+100 μm

500+300 μm

1000+500 μm

Propor.of basalt

34568

30%

40%

50%

60%

80%

Prop.ofaccelerator

a 0.2%

b 0.6%

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Fig.2.Wearresistancetestsample.

Fig.3.TribologicalandWearresistancetestingdevice.

4. TESTRESULTS Theprocedureforwearresistancetestingisthefollowing: rotary abrasive disc made of steelwith a diameter of 148 mm overlaps thepreparedsample.Thediscrotateswithspeedof0.05 RPMwith 200 revolutions on one sample(Fig.3).Thehigherspeedisnotpossiblebecausethe samples arequicklyheatedandburn.Wearresistanceisdefinedasthelossofmassperunitof wear surface. Wear surface in this case is asemi‐spherical, so it can be calculated by theexpression:

2,0037.10180

cmr

alaPo

where:a‐widthofthesample(whichis3.1cm)l‐lengthoftheport(whichis3.227cm)φ ‐central angle (anglewhichcovers the lengthofthearcwhichis0.43633rad).The loss of mass per surface unit can becalculatedusingthefollowingequation:

21 ,cm

g

P

mO

ThevaluesofmasslossareshowninTable5.Table5.Testresultsofwearresistance.

Sampledesignation

Mass beforetestingm0(g)

Mass aftertestingm(g)

Masslossm1(g)

MasslossreducedtowearsurfaceO(g/cm2)

I3a 11.36 11.330 0.030 0.00299I3b 10.29 10.270 0.020 0.00199I4a 10.64 10.610 0.030 0.00299I4b 10.93 10.895 0.035 0.00349I5a 12.60 12.585 0.015 0.00249I5b 11.50 11.480 0.020 0.00199I6a 12.71 12.695 0.015 0.00149I6b 11.87 11.855 0.015 0.00149I8a 13.70 13.675 0.025 0.00249I8b 13.57 13.560 0.010 0.00299II6a 12.16 12.140 0.020 0.00199II6b 12.96 12.950 0.010 0.00099III6a 12.20 12.180 0.020 0.00199III6b 12.64 12.620 0.020 0.00199IV6a 12.37 12.360 0.010 0.00099IV6b 12.54 12.530 0.010 0.00099V6a 13.42 13.400 0.020 0.00199V6b 13.52 13.510 0.010 0.00099

4.1.DiscussionoftheresultsTable5showsthevaluesofthemassofsamplesbeforeandafterwearmass lossandmass lossreducedtowearsurface.BasedontheresultsinTable 5 a histogram of mass loss per wearsurfaceismade(Fig.4).

Fromtheabovehistogramcanbeconcludedthatthe least amount of lost material are on thesamples with the designation I6a and I6bcontaining 60% basalt powder and grain size150+50 μm. Content of accelerator in the firstsampleis0.2%,andinthesecond0.6%.

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Fig.4.Histogramofsamplesmassloss.Since these samples showed the best wearresistancewe continued to test sampleswith a60% of basalt powder, butwith different grainsize.Figure5showshistogramthemasslossperwearsurface.

Fig.5.Histogramofsamplesmassloss.Onthediagramitisevidentthatthebestvaluesof wear resistance have the samples IV6a andIV6b.Thesesamplescontain60%basaltpowderwith a grain size of 500+300 μm. Content ofaccelerator in the first case is 0.2%, and in thesecond 0.6%. This clearly indicates that thespecifiedgranulationofbasaltpowdergivesthehighestwearresistance.5. CONCLUSION Goodcharacteristicsofbasaltqualifythemforthefinalworks in construction andmanufacturingofbasaltwool,usedasinsulatingmaterial.Duringtheresearch, the technological parameters of theproduction of polymer matrix composites withbasalt as reinforcements are established. Furtherdevelopment of these materials will go in the

direction of its application for the production ofparts in the automotive industry and foodproduction[1011].Samplesgenerallyshowedveryuniformvaluesof wear resistance. However a certain numberofsampleshavereducedvalueofmass lossperwear surface, which is especially noticeable onthesamples:I6aI6b,IV6aandIV6b.Thismeansthatthewearresistanceof thesesamples is thebest, and in future work should use thesetechnological parameters.Abroader viewof alltheseresultsisgiveninthepapers[789].Technology of the production and design ofthese composites is now less known in theworld. For the production of such compositesshould define in more detail the technologicalparameters, equipment, tools, etc. It willprobablybethetaskoffutureresearch.REFERENCES[1] K. Flinn R. Trojan: Engineering materials and

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[8] TodićR.AleksićD.ČikaraT.Todić:Researchofparticulate composites based onpolyester resinsand basalt, IMK – 14 Oktobar Research anddevelopment(28‐29)1‐2/2008.pp.37‐42.

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[9] TodićD.Čikara,T.TodićB.Ćirković:ToughnesstestingofparticulatecompositesbasedonbasaltpolymerandsilaneIMK–14OktobarResearchanddevelopment(32‐33)3‐4/2009.pp.25‐28.

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