New$diamond$composite$ultrahard$material$for$drilling$of$hard$rocks$

Sergei&Sobolev&Russian&State&University&of&Oil&and&Gas&

Supervisor:&E.E.&Ashkinazi&Prokhorov&InsAtute&of&General&Physics&&&

Shortly$about$the$department$

There%are%7%research%laboratories%in%the%department:%•&Laboratory&of&metallographics&•&Laboratory&of&corrosion&•&Laboratory&of&tribology&•&Laboratory&of&microFarc&oxidaAon&•&Laboratory&of&soldering&and&restoraAon&of&diamond&tools&•&Laboratory&of&ion&vacuum&coaAngs&

2&

www.gubkin.ru&&

Application$

Currently,&diamond&tools&are&mainly&used&for&drilling&hardest&rocks.&Materials&with&improved&wear&resistance&need&to&be&used&for&drilling&on&oilfields&(for&example&sea&shelf,&oil&and&gas&fields&in&Eastern&Siberia,&etc.).& 3&

Core$drill$bits$with$diamond$inserts$

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One&type&of&rock&destrucAon&tool&is&a&diamond&core&drill&bits.&The&main&element&of&a&core&drill&bit&is&a&diamond&cuSer.&

diamond&cuSer/inserts&

Disadvantages+of+currently+used+core+drill+bits++

5%

•  Insufficient&removal&of&the&sludge&(debris)&from&the&acAve&zone&•  Uneven&wear&of&sectors&of&core&drill&bits&•  Fast&wear&of&diamond&inserts&•  Insufficient&cooling&•  Insufficient&fixing&of&insert&with&a&matrix&&•  Not&opAmized&size&of&diamond&grains&in&the&matrix&•  Not&opAmized&locaAon&of&diamond&inserts&in&the&cuSer&

We&have&analyzed&the&patents&from&different&countries&over&the&last&fiZy&years.&Currently,&there&are&disadvantages&of&diamond&core&drill&bits&as&following:&

Analysis+of+patents.+Results+

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As%a%result:%F&Low&drilling&speed&F&High&wear&of&the&core&drill&bits&F&Low&energy&efficiency&

NB!%Presently,%the&wear&mechanisms&during&drilling&of&hardest&rocks&by&a&core&drill&bit&are&the&polishing/grinding&(because&hardness&of&

cuSers&is&only&approximately&50&GPa).&

Examples&of&the&polishing/grinding/cu_ng&wear&mechanisms&will&be&shown&in&the&next&slides.&

It%is%very%important%to%stress%difference%in%abrasive%mechanisms%%(polishing/grinding/cu_ng).&

Difference$in$abrasive$mechanisms$$

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Polishing/Grinding%%homogeneous&sludge&(debris)&&

size%of%50*80%micron%

Grinding/CuCng%nonhomogeneous&sludge&(debris)&&sizes%of%50*80%and%100*200%micron%

Analysis+of+patents.+Decisions+

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The%properDes%of%the%diamond%core%drill%bit%must%be%improved:%•  To&provide&the&combinaAon&of&two&processes,&the&grinding&and&cuCng.&This&is&possible&if&there&is&an&element&of&hardness&of&100&GPa&or&more.&

•  To&use&materials&with&different&hardness&in&the&structure&of&matrixFcompositeFdiamond&(25/50/100+&GPa).%

&But%hardness%of%100%GPa%is%the%hardness%of%the%natural%diamond,%which%means:%(а)&high&cost&(b)&not&opAmal&shape&of&cuSer&(octahedron)&&&

Hybrid+Ultrahard+Material$

Therefore&the&Bakul&InsAtute&for&Superhard&Materials&(NaAonal&Academy&of&Sciences&of&Ukraine)&and&Prokhorov&InsAtute&of&General&Physics&(Russian&Academy&of&Sciences)&developed&hybrid&ultrahard&polycrystalline&composite&material&(UHM)&with&a&polycrystalline&diamond&grown&by&CVD&method&(CVD&diamond).&

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The%problem%can%be%solved%by%using%CVDLdiamond%(hardness%140%GPa)%

Hybrid+Ultrahard+Material$

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•  Hardness&of&CVDFdiamond&is&140&GPa&(40&GPa&higher&than&natural&diamond).&•  The&shape&of&CVDFdiamond&insert&is&a&plate&(thickness&of&the&insert&does&not&

change&during&drilling).&

CVD&diamond&size:&4,0×1,0×0,5&mm&(length&x&width&x&thickness)&

DCTM%&

The&ultrahard&hybrid&material&(UHM)&includes&CVDFdiamond&insert&and&diamond&composite&thermostable&materials&(DCTM)&matriх&(around&CVDFdiamond&insert&)&The%UHM%has%the%following%properDes:%

Vickers$hardness$of$CVD>diamond$insert$

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The&hardness&value&was&found&by&the&following&formula&&HV#=#1.8544#*P/d2,&&

&

where&P%is&the&indentaAon&load,&d%is&the&arithmeAcal&mean&of&two&diagonals&of&the&indent.&&&The&indent&diagonals&were&measured&using&a&Neophot&opAcal&microscope&at&

a&magnificaAon&of&х800.&

The&UHM&hardness&was&measured&on&a&PMT&microtester&with&a&Vickers&diamond&pyramid&as&an&indenter&at&indentaAon&loads&of&4.9%and%9.8%N.%%

Patents+(Russia+and+Ukraine)$

12&

«Diamond%polycrystalline%composite%with%the%

reinforcing%diamond%component»%

Authors:%E.E.&Ashkinazi,&V.G.&Ral’chenko,&V.I.&Konov,&A.P.&Bolshakov,&S.&G.Ryzhkov,&S.S.&Sobolev&

Categories:%C04B35/528,&B24D3/04&

Date%of%applicaDon:%2013F07F19&Date%of%the%publicaDon:%2015F10F01&

This&UHM&material&is&protected&by&patents&in&Russia&and&Ukraine.&

The$hardness$gradient$

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Applying%of%an%ultrahard%component%(CVDLdiamond)%allows:%(a)&prefracture&of&rocks&by&cu_ng&as&a&wear&mechanism&(b)&progressive&rock&shredding&(c)&removing&drilling&sludge&(debris)&from&the&contact&area&(d)&increase&in&the&service&lifeAme&of&diamond&inserts&(d)&increasing&energy&efficiency&and&durability&core&drill&bit&

CVDLdiamond%(140%GPa)%%

DCTM%(~50%GPa)%

Diamond%matrix,%%body%of%the%drill%bit%(~25%GPa)%

Another&property&of&material&is&the&hardness&gradient.&

Structure$of$Ultrahard$Hybrid$Material$(UHM)$

UHM&is&a&diamond&polycrystalline&composite&with&CVDFdiamond&insert.&Composite&includes&the&dispersible&strengthening&addiAve&and&powders&of&diamond&and&metals.&&

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Structure,%Mas.%%%

Diamond&powder&and&CVD&diamond&insert&& 85F90&

Nickel&& 7F9&

Cobalt&& 2F4&

Nanopowder&of&tungsten&carbide&& 0,1F3,0&

The&UHM&was&sintered&in&a&high&︎pressure&process&in&two&stages:&&1.  At&the&first&stage&the&material&was&subjected&to&heat&treatment&at&a&

pressure&of&8&GPa&and&temperature&of&1170&K&for&50&s.&&2.  Then&the&temperature&was&increased&to&the&silicon&melAng&point&

temperature&(1570&K)&at&the&given&pressure&and&held&for&90&s.&

Chemical&Vapor&DeposiAon&(CVD)&of&diamond&

CVD&diamond&was&deposited&in&Methane&(CH4)/Hydrogen&(H2)&plasma&in&the&microwave&oven&on&Si&substrate&on&the&UPSAF100&unit&•  power&F&5&kW,&&•  frequency&F&&2,45&GHz,&•  gas&pressure&in&the&camera&F&95F100&Torr,&&•  concentraAon&of&CH4&F&10%,&&•  temperature&of&a&substrate&F&850F870&°C,&&•  deposiAon&rate&~&5,0&microns/h.&&&

AZer&deposiAon&the&diamond&plate&was&detached&from&Si&substrate&by&solving&of&substrate&in&acid&(HF).&Plate&was&cuSed&into&smaller&pieces&by&means&of&a&laserFbeam&technique.& 15&

Research$Hybrid&Ultrahard&Material&

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Turning$of$Korostyshev$granite$

The%main%task&was&to&study&wear&mechanisms&of&DCTM&with/without&CVDFdiamond&insert.&Two&samples&were&used:&

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&DCTM&without&CVD&diamond&& DCTM&with&CVD&diamond&&

DCTM%–%diamond%composite%thermostable%material%

The&wear&resistance&of&a&rock&destrucAon&tool&equipped&with&UHM&was&esAmated&in&a&turning&test&against&Korostyshev&granite&(drillability&index&–&XI,&high&hardness,&high&abrasive&resistance).&Test&was&done&on&the&DIPF200&screwFcu_ng&lathe.&

Properties$of$granite$Granite%is%used%as%a%hard%rock%material.%Its%properDes:%

• MediumFgrained&(the&size&of&grains&is&from&2&to&5&mm)&• Average&density&is&2600F2800&kg/m3&• Weak&porosity&(to&1,5%)&• Slight&water&absorpAon&(0,5%)&• Good&resistance&to&an&abrasion&• Compressing&strength&90&…&280+&MPa&

СomposiDon%of%granite:%• Feldspars&(about&40.&60%),&• Quartz&(20.&40%)&• IronFmagnesium&silicates&(to&10%)&• Micas&and&etc.&

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Wear$tracks$on$a$cylindrical$Korostyshev$granite$sample$$

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Wear$mechanism+

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DCTM%%

Polishing/Grinding%%homogeneous&sludge&(debris)&&

size%of%50*80%micron%

DCTM%with%CVD%%

Grinding/CuCng%nonhomogeneous&sludge&(debris)&&sizes%50*80%and%100*200%micron%

Wear&intensity&(mg/m)$Wear&intensity&on&DCTM+CVDFdiamond&insert&is&several&Ames&smaller&(5,5&Ames&for&black&CVD&and&10,4&Ames&for&white&CVD)&than&wear&intensity&on&DCTM&sample&without&CVDFdiamond&

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Wear&intensity,&10F3&mg/m&&

Wear%intensity%%=%∆m%/%L%∆m&&F&weight&loss,&mg&&L&F&path&length,&m&&

Effect$of$«Self>sharpening»$

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It&should&be&noted&that&there&is&an&interesAng&effect&of&«selfFsharpening».&It&is&the&emergence&of&a&cone&with&sharp&edges&on&the&surface&of&DCTM&with&CVDFdiamond&insert.&This&effect&improves&the&abrasive&ability&of&the&cuSer.&

Tests$on$abrasive$wheels$

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Equipment%was%designed%for%the%study%of%tribological%properFes%of%

diamond%drilling%cuGer.%

Equipment$layout$

24&KinemaFc%scheme%

Sample$loading$setup$

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Abrasive%wheel%•  Electrocorundum&•  Ceramic&matrix&•  Size&of&the&main&fracAon&of&600F700&microns&•  K6V2&brand&25&and&60&with&a&graininess&60&

Samples%•  DCTM&•  DCTM&with&CVDFdiamond&

Load&6F80&N&

Experimental$conditions$

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•  Load&F&6F80&N&•  Time&of&tests&–&12&s&F&30&min&•  RotaAon&frequency&F&31F69&rpm.&

DCTM&and&DCTM+CVDFdiamond&samples&were&weighed&with&an&accuracy&of&±0,0001&g&(ViBRA&HD).&&

The&trajectory&of&the&sample&is&a&spiral&(«step»&F&5&and&10&mm).&&

Results$

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DCTM+CVD&DCTM&

Weight&loss,&mg&

Distance,&m

&

For&the&same&weight&loss&the&distance&in&the&case&of&DCTM&samples&was&about&10&Ames&smaller&than&in&the&case&of&DCTM+CVDFdiamond&samples.&&&

In&other&words,&the&lifeAme&of&DCTM+CVDFdiamond&samples&is&about&10&Ames&longer&than&for&DCTM&samples.&

Friction$tests$against$silicon&carbide$(SiC)$(Tribometer$T>10)$

The%main%task:%•  Measurement&of&fricAon&

coefficient.&•  Measurement&of&the&wear&

intensity&(mg/h)%on&silicon&carbide&against&DCTM&and&DCTM&with&CVDFdiamond&&samples.&

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The$results$of$friction$test$on$DCTM$sample$

•  Load&Q=20F50N,&&•  RotaAon&frequency&N=50&rpm&•  Sliding&speed&Vck=0,1&m/s,&&•  Diameter&of&the&sample&d=4&mm.&

•  Total&Ame&of&the&experiment:&57,9&h&•  Total&weight&loss:&∆m&=&5&mg&•  Wear&intensity&(mg/h):&VDCTM=0,086&mg/h& 29&

FricDon%coefficient:%0,1F0,15&%%

The$results$of$friction$test$on$DCTM$with$CVD>diamond$insert$sample$

•  Load&Q=20F50N,&&•  RotaAon&frequency&N=50&rpm&•  Sliding&speed&Vck=0,1&m/s,&&•  Diameter&of&the&sample&d=4&mm.&

•  Total&Ame&of&the&experiment:&2,0&h&•  Total&weight&loss:&∆m&=&41&mg&•  Wear&intensity&(mg/h):&VDCTM+CVD=20,5&mg/h&

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FricDon%coefficient:%0,11F0,48&%

Comparison$of$the$results$

•  Wear&intensity&on&silicon&carbide&sample&(speed&of&weight&loss,&mg/h)&against&DCTM&with&CVDFdiamond&insert&in&dry&sliding&fricAon&is&about&240&Ames&higher&than&wear&intensity&against&DCTM&without&CVDFdiamond.&

•  FricAon&coefficient&in&dry&sliding&fricAon&for&silicon&carbide&against&DCTM&sample&is&smaller&than&against&DCTM+CVDFdiamond&(fDCTM=0,1F0,15,&fDCTM+CVD=0,11F0,48).&

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Surface$structure$of$DCTM$(20x20$mkm)$

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Surface$structure$of$CVD>diamond$(20x20$mkm)$

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Surface$structure$of$sample$(closeup)$

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500x350mkm&

From&previous&two&slides&we&can&conclude&that&the&porosity&and&roughness&of&CVDFdiamond&is&smaller&

than&that&of&DCTM&matrix.&

DCTM&matrix&

CVDFdiamond&&

Main$conclusions$

1.  DCTM+CVDFdiamond&insert&samples&showed&beSer&performance&than&DCTM&samples.&

2.  The&results&of&the&present&study&may&have&a&substanAal&importance&for&the&development&of&drilling&tools&(core&drill&bits).&

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Thanks+for+your+attention!$

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