DEC material is a novelty on the tool material market. It is based on the latest achievements in material engineering, providing very high wear resistance. Thanks to the enrichment of tungsten carbide with diamond, using PPC technology, this material exceeds the life of conventional tungsten carbide many times, giving way only to PKD tools but offering lower price. Due to the wide range of possibilities of shaping DEC microstructure and therefore its properties, the potential applications include woodworking, mining, ceramic processing or road surface milling.

 

DEC material is a novelty on the tool material market. It is based on the latest achievements in material engineering, providing very high wear resistance. Thanks to the enrichment of tungsten carbide with diamond, using PPC technology, this material exceeds the life of conventional tungsten carbide many times, giving way only to PKD tools but offering lower price. Due to the wide range of possibilities of shaping DEC microstructure and therefore its properties, the potential applications include woodworking, mining, ceramic processing or road surface milling.

Near net shaped DEC picks. Mining and road planning applications require tools that offer both abrasion and impact resistance. PCD inserts would have high abrasion resistance with low impact resistance, whereas tungsten carbide tools would resist impact loading. Thus, the functionally graded picks with diamond enhanced carbide tips on tungsten carbide substrates are introduced for these applications. The NNS picks were sintered using pulse plasma compaction sintering method PPC. Fig. 2 represents typical sintering profile of the picks.

APPLICATIONS

SAW BLADES and MILLING CUTTERS for machining of wood-based materials

Road maintenance and Oil&Gas drilling

The highest hardness and resistance to abrasion in the mining and drilling cutters ends b y proper selection of the proportion and particle size of diamonds and the binding phase. Required toughness when milling the surface by proper selection of tungsten carbide grain size.

CFRP composite (Carbon – Fibre – Reinforced – Polymer)

High impact-resistance combined with a high degree of hardness quarantess good-quality performance. The opportunity of applying the appropriate tool geometry ensures the quality of the surface after machining.

Aluminum and aluminum alloys

High impact-resistance combined with a much higher degree of hardness and an opportunity to apply the appropriate geometry for aluminium alloys interrupted cutting ensures the quality of the surfaces after machining and a stable and quiet operation.

 



Please keep in mind that the applications we provide are merely an example. If you suspect that our material may be used in different branch, use case or application please contact us and we will test it together.

Polycrystalline diamond PCD sintered with transition metal catalysts such as cobalt and nickel are reckoned for its highest strength and hardness amongst engineering materials making it the first-choice materials for inserts used in abrasion applications. The sintering conducted by infiltration of liquid metal catalyst, however, requires the application of high pressure to prevent the conversion of diamond particles into graphite as shown in the equilibrium phase diagram in Fig. 1. Current sintering practice is conducted the catalytic HPHT synthesis region of pressure and temperature. The thermal degradation of PCD insert, and their cracking are ascribed to the graphitization of diamond and to the thermal expansion mismatch between the cobalt binder (12 × 10–6 K–1) and the diamond particles (0.7 ×10–6 K–1), which results in the occurrence of residual tensile stresses in diamond particles. Typical five hundred micrometers layers are leached to improve the performance of PCD cutters. However, leaching the PCD layer sintered under pressure above 6 GPa is time consuming, and takes weeks to achieve the required leached depth.

Ciśnienie stosowane podczas spiekania wynosi od 60 do 90 MPa i zmienia się w zależności od geometrii matryc grafitowych, aby zapobiec pękaniu w matrycy.
grafitowych matryc, aby zapobiec pękaniu w ostrych narożach oprzyrządowania. Ten zakres ciśnień jest sto razy niższy niż typowe zakresy dla spiekania w fazie ciekłej frezów z polikrystalicznego diamentu PCD w prasach HPHT. W metodzie spiekania plazmą impulsową pełną gęstość uzyskuje się w elementach DEC spiekanych w temperaturze około 1240°C, znacznie poniżej temperatury topnienia kobaltu. Uważa się, że spiekanie w stanie stałym mieszanin proszków DEC uniemożliwia pełną aktywność katalityczną kobaltu do grafityzacji cząstek diamentu ze względu na niską rozpuszczalność węgla w stałych cząstkach kobaltu i szczęście zwilżalności cząstek diamentu. Zatem ograniczenie konwersji diamentu do grafitu poprzez szybkie ogrzewanie pod niskim ciśnieniem poniżej linii Birmana-Simona.

Products

■ Case 1. Near net shaped DEC picks. Mining and road planning applications require tools that of-

fer both abrasion and impact resistance. PCD inserts would have high abrasion resistance with low impact resistance, whereas tungsten carbide tools would resist impact loading. Thus, the functionally graded picks with diamond enhanced carbide tips on tungsten carbide substrates are introduced for these applications. The NNS picks were sintered using pulse plasma compaction sintering method PPC. Fig. 2 represents typical sintering profile of the picks.

Fig. 3 illustrates the NNS products thus manufactured and typical microstructures of the tip volume of the picks made of DEC bonded on tungsten carbide substrates. The PPC method of sintering produced crack-free picks with no-delamination between the DEC and the tungsten carbide layers. Delamination often decreases the production yield of liquid phase sintering with infiltration of the metal catalyst in this type of products. In that case, solidification shrinkage of large volume of liquid under the DEC – tungsten carbide substrate interface would generate elevated tensile residual stresses that lead to its delamination. The hardness of the tungsten carbide layers thus sintered varied between 15.5 and 16.5 GPa and the KIC calculated using the Anstis and JISR 607 formula varied between 22 and 34 MPa m1/2, almost twice that of PCD. These values are on the upper end of tungsten carbide of submicron particle sizes sintered with low cobalt contents.

Conclusion

  • The pulse plasma compaction technology has enabled the sintering of near net shape prototype cutters for mining, road planning and drilling applications.
  • The large volume sintering chambers accommodate longer capsules than the HPHT vehicles used in PCD sintering, thus enabling sintering large functionally graded tools with DEC pre-shaped tips on tungsten carbide shanks.
  • Pulse plasma compaction solid state sintering prevents the volume shrinkage near the interfaces be-tween DEC and tungsten carbide layers, thus avoiding the residual tensile stress state that would lead to delamination between the layers.
  • The sintered DEC layers typically have intermediate performance in hard rock cutting between poly-

crystalline diamond and tungsten carbide cemented inserts.

  • The hardness and the fracture toughness values of the tungsten carbide substrate shanks of the functionally graded picks sintered by pulse plasma compaction technology are on the upper end of incumbent fine grain materials sintered by infiltration of liquid cobalt