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

1. 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&&
&

2. 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&&

3. 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&

4. Core$drill$bits$with$diamond$inserts$
4&
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&

5. 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:&

6. Analysis+of+patents.+Results+
6&
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).&

7. Difference$in$abrasive$mechanisms$$
7&
Polishing/Grinding%%
homogeneous&sludge&(debris)&&
size%of%50*80%micron%
Grinding/CuCng%
nonhomogeneous&sludge&(debris)&&
sizes%of%50*80%and%100*200%micron%

8. Analysis+of+patents.+Decisions+
8&
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)&
&
&

9. 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).&
9&
The%problem%can%be%solved%by%using%CVDLdiamond%(hardness%140%GPa)%

10. Hybrid+Ultrahard+Material$
10&
• 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:%

11. Vickers$hardness$of$CVD>diamond$insert$
11&
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.%%

12. 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.&

13. The$hardness$gradient$
13&
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.&

14. Structure$of$Ultrahard$Hybrid$Material$(UHM)$
UHM&is&a&diamond&polycrystalline&composite&with&CVDF
diamond&insert.&Composite&includes&the&dispersible&
strengthening&addiAve&and&powders&of&diamond&and&metals.&&
14&
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.&

15. 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&

16. Research$
Hybrid&Ultrahard&Material&
16&

17. Turning$of$Korostyshev$granite$
The%main%task&was&to&study&wear&mechanisms&of&DCTM&with/without&CVDF
diamond&insert.&Two&samples&were&used:&
17&
&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.&

18. 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.&
18&

19. Wear$tracks$on$a$cylindrical$
Korostyshev$granite$sample$$
19&

20. Wear$mechanism+
20&
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%

21. 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&
21&
Wear&intensity,&10F3&mg/m&&
Wear%intensity%%=%∆m%/%L%
∆m&&F&weight&loss,&mg&
&L&F&path&length,&m&
&

22. Effect$of$«Self>sharpening»$
22&
It&should&be&noted&that&there&is&an&interesAng&effect&of&«selfF
sharpening».&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.&

23. Tests$on$abrasive$wheels$
23&
Equipment%was%designed%for%the%study%of%tribological%properFes%of%
diamond%drilling%cuGer.%

24. Equipment$layout$
24&KinemaFc%scheme%

25. Sample$loading$setup$
25&
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&

26. Experimental$conditions$
26&
• 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).&&

27. Results$
27&
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.&

28. 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.&
28&

29. 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&%%

30. 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&
30&
FricDon%coefficient:%0,11F0,48&%

31. 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+CVDF
diamond&(fDCTM=0,1F0,15,&fDCTM+CVD=0,11F0,48).&
31&

32. Surface$structure$of$DCTM$(20x20$mkm)$
32&

33. Surface$structure$of$CVD>diamond$(20x20$mkm)$
33&

34. Surface$structure$of$sample$(closeup)$
34&
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&&

35. 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).&
35&

36. Thanks+for+your+
attention!$
36&
Сергей Соболев
sobolev.ceo@gmail.com