Polycrystalline diamond (PCD) composite is a kind of composite material which has the high wear resistance of PCD and the high impact resistance of cemented carbide by attaching PCD thin layer to cemented carbide substrate Has sharp edge of diamond layer and the sharpness, can always stay sharp cutting edges, therefore very suitable for petroleum and geological drilling in hard formation in soft formation until exploration, the effect is very good In polycrystalline diamond compact diamond content as high as 99%, so the diamond layer hardness is very high Excellent wear resistance, its knoop hardness 104 ~ 7.0 to 6.5 104MPa or more.
The carbide matrix overcomes the shortage of hard and brittle polycrystalline diamond and greatly improves the impact toughness of the product. The easy weldability of cemented carbide solves the problem that polycrystalline diamond is difficult to be combined with other materials by welding method, and the polycrystalline diamond composite sheet can be vertically inserted and welded on the drill bit.
Compared with single crystal diamond, polycrystalline diamond (PCD) and polycrystalline diamond composite blade (PDC) as tool materials have the following advantages:
(1) The grains are disordered, isotropic and have no cleavage plane. Therefore, unlike large single crystal diamond, there are great differences in strength, hardness and wear resistance on different crystal planes, and brittleness due to the existence of cleavage plane.
(2) With high strength, especially PDC material due to the support of the carbide matrix and has a high impact strength, when the impact is large will only produce small grain breakage, and not like single crystal diamond as large collapse, so PCD or PDC tool can not only be used for precision cutting and ordinary semi-precision machining, It can also be used for rough machining and discontinuous machining (such as milling, etc.), which greatly expands the scope of use of diamond tool materials.
(3)Large PDC diamond composite blade cutter billet can be prepared to meet the needs of large processing tools such as milling cutter.
(4) It can be made into specific shapes to meet the needs of different processing. Triangular, herringbone and other special-shaped cutter blanks can be processed and formed due to the large scale PDC cutter and processing technology such as edM and laser cutting technology. In order to meet the needs of special cutting tools can also be designed into package type, sandwich type and twist type PDC cutter blank.
(5) The performance of a product can be designed or predicted to give it the necessary features to suit its specific use. For example, the choice of fine-grained PDC tool material can improve the quality of the cutting edge of the tool, coarse-grained PDC tool material can improve the durability of the tool, etc
In short, with the research progress of PCD and PDC diamond composite cutting tool materials, their application has been rapidly extended to many manufacturing industries. Widely used in non-ferrous metal (aluminum, aluminum alloy, copper, copper alloy, magnesium alloy, zinc alloy, etc.), cemented carbide, ceramics, non-metallic materials (plastic, hard rubber, carbon rod, wood, cement products, etc.), composites (fiber reinforced plastic, metal matrix composites MMCs, etc.) of machining, especially in the wood and automobile industry, It has become a high performance substitute for traditional cemented carbide products.
PDC PCD material requirements for cutting tools:
D-D self-bonding can be widely formed between diamond particles, and the residual bonding metal and graphite should be as little as possible. The bonding metal should not be distributed in the form of coalesce or vein, so as to ensure the tool has higher wear resistance and longer service life, and the residual amount of solvent metal is less * is a solvent effect during the sintering process, the sintering process is completed with no solvent effect in the form of alloy in sintering diamond grain filling clearance, or residual solvent after sintering of metal quarantined, avoid direct contact with the solvent metal and diamond surface, in order to improve the oxidation resistance of PCD, thus ensuring cutting tools with sufficient heat temperature Diamond grains are small and uniform, and abnormal growth grains are not allowed to improve the impact toughness of the material. The bonding interface between the PCD layer and the matrix or the welding (intermediate) transition layer has high bonding strength and good thermal conductivity, so as to reduce the temperature of the cutting edge.
PDC composite (polycrystalline diamond composite) is a composite superhard diamond product which is synthesized by the polymerization of polycrystalline diamond layer and hard alloy substrate through ultra-high temperature and high pressure technology. It has the advantages of high hardness, abrasion resistance, impact resistance and high temperature resistance, and is mainly used in the fields of oil drilling and coal mining drills.
----EDITOR: Doris Hu
----POST: Doris Hu