| 摘要 |
#CMT# #/CMT# Production of an element involves depositing coating material over at least part of block (1) surface having dense material constituted by hard particles dispersed in binder phase, leaving free at least one imbibition area of the surface; contacting imbibition area with imbibiting material (preferably pellet (2)) which locally enriches the block with binder phase; and subjecting resultant block to thermal cycle including heating, temperature maintenance and cooling, to bring some of imbibiting material and binder phase into liquid state. #CMT# : #/CMT# Production of an element involves depositing a coating material over at least part of a block (1) surface having dense material constituted by hard particles dispersed in a binder phase, leaving free at least one imbibition area of the surface; bringing the imbibition area into contact with an imbibiting material having properties which support locally enriching the block with binder phase; and subjecting the resultant block to a suitable thermal cycle, constituted by heating, temperature maintenance and cooling, which brings at least some of the imbibiting material and the binder phase of the block into the liquid state, so as to locally and gradually enrich the dense material block with binder phase by imbibition through the imbibition area. The coating material prevents migration of the imbibiting material through walls of the block on which it is deposited and modifies kinetics of migration of the binder phase into the block so as to create a gradual binder phase distribution. The method also involves depositing on one face of the block after imbibition a diamond table of either the polycrystalline diamond compact (PDC) or thermally stable polycrystalline diamond (TSP) type. An independent claim is included for a cutter comprising a block constituted by hard particles dispersed in a binder phase, and having a composition gradient of binder phase and a shape having a function of a tool; and with respect to the composition gradient, the block has a core, which is more rich in binder phase, and a surface with a low binder phase content of high hardness, with a continually varying binder phase gradient existing between it. #CMT#USE : #/CMT# For the production of an element including cutter (claimed) and tools for use in oil and gas and/or mine drilling. #CMT#ADVANTAGE : #/CMT# The method provides the blocks with both very good wear resistance at the surface and good core toughness, so as to have an improved lifetime as compared with that of conventional tools. The coating material increases the interfacial energy between the binder phase and the carbide phase and thus has an effect on the migration of the binder phase to the inside of the block. The method permits the production of blocks which are to constitute tool bits, has the advantage of allowing blocks to be obtained whose outside portion is hard and whose inside portion is tough. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The figure shows a diagram of the production, by imbibition, of a dense cermet block having a hard outside surface and a tough core. 1 : Block 2 : Imbibiting material (pellet) 7 : Coating layer 8 : Aluminum oxide 9 : Oven. #CMT#INORGANIC CHEMISTRY : #/CMT# The pellet is constituted by an agglomerated powder mixture, one face of which is in contact with the surface of the block. The block further comprises natural or synthetic diamond particles, of a size up to 1 mm in diameter. The solid particles constituting the material of the block comprise hard metal carbide particles, where the binder phase is of metallic nature. The imbibiting material has chemical composition comprising an eutectic (at least 85 wt.%) formed between the metal carbide particles of the block and the binder phase, such that a difference between a melting point of the second binder phase of the imbibiting material and the binder phase of the block is less than 200[deg] C; and at least one metal elements (not > 15 wt.%) selected from copper (Cu), silica (Si), manganese (Mn), chromium (Cr), molybdenum (Mo), tungsten (W), vanadium (V), niobium (Nb), tantalum (Ta), titanium (Ti), zirconium (Zr) or hafnium (Hf). The material constituting the block is a cermet of the WC-Co or WC-(Co and/or Ni and/or Fe) type, which optionally includes diamond particles, where the imbibiting material is of the WC-M type (where M is selected from at least one metal selected from Co, Ni and Fe). The cermet constituting the block is of the WC-Co type and comprises cobalt (not more than 35%), and the imbibiting material has a cobalt content of from 35 to 65% by weight. The coating layer comprises a material selected from boron nitride, graphite or aluminum oxide. |
