Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/34—Nitrides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
  • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
  • B23K35/24—Selection of soldering or welding materials proper
  • B23K35/32—Selection of soldering or welding materials proper with the principal constituent melting at more than 1550 degrees C
  • B23K35/327—Selection of soldering or welding materials proper with the principal constituent melting at more than 1550 degrees C comprising refractory compounds, e.g. carbides
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
  • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
  • C23C16/36—Carbonitrides
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C30/00—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process
  • C23C30/005—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process on hard metal substrates
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/26—Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
  • Y10T428/263—Coating layer not in excess of 5 mils thick or equivalent
  • Y10T428/264—Up to 3 mils
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal

Definitions

• Machine parts made of hard metal comprising at least one metal carbide and a metal binder may be provided with an improved wearand abrasion-resistance by forming a nitride or carbonitride surface layer thereon of one or more metals of Groups IVa to Vla of the Periodic Table.
• a surface layer of titanium nitride or carbonitride is formed.
• the invention also provides a method of producing such surface layers which includes the step of heating the machine parts in the presence of a thermally-decomposable metal halide and a purified gas mixture of nitrogen, hydrogen and possibly methane.
• This invention relates to the provision of an abrasionand wear-resistant coating on hard metal parts used for machining and plastic forming, to protect said parts from abrasion and wear.
• the cutting surface of metal tools which are used for machining materials which form long and short chips are always subject to some degree of abrasion which shortens the life of the tool.
• a known technique for preventing this is to sinter coating layers of titanium-carbide cobalt hard metal on cutting tools made of tungstencarbide cobalt hard metal. This is intended to preserve the toughness of the base material and also to make use of the high resistance to abrasion of titanium-carbide containing metals.
• the differential coefficients of thermal expansion and the varying sintering stresses between the coating layer and the base material nevertheless cause cracks to occur, and for this reason such composite hard metal surface layers have not been a success.
• a recent development in protecting the surface of hard metal cutting tools is to deposit a hard titanium carbide coating layer less than 10 m. thick by vaporisation. Such a layer provides some improvement in the abrasive wearing properties of the tool.
• metal nitrides or of metal carbonitrides of metals as hereinafter described have better abrasion resistance than conventional titanium carbide coating layers on hard metal parts comprising at least one metal carbide and a metal binder, e.g. iron, cobalt and/or nickel.
• metal binder e.g. iron, cobalt and/or nickel.
• metal nitrides and metal carbonitrides are not as hard as metal carbides their resistance to abrasive wear is higher. Among other factors this may be due to the nitrided hard metals being less liable to weld and stick to metal chips and their oxide skins than metal carbides.
• the invention provides a machining part made from a hard metal comprising at least one metal carbide and a metal binder, having a surface layer consisting of a nitride or carbonitride of one or more metals of Groups IVa to VIa of the Periodic Table of Elements.
• German patent specification 1,056,450 describes coating layers of metal carbides, nitrides, borides and silicides on objects made of tool steel or cast iron.
• German patent specification No. 1,065,442 describes the provision of workpieces and tools made of steel with coatings of titanium carbide and titanium nitride.
• the coating layer consists of titanium nitride or titanium carbonitride.
• titanium carbonitride it is preferred that from 10% to 20% titanium carbide is present in the crystalline carbonitride solid solution.
• the thickness of the coating on the hard metal parts may be between 1 and 50 ,um.
• the nitride or carbonitride is deposited on the surfaces of hard metal parts by thermal decomposition of a halide of a metal of Groups IVa to VIa of the Periodic Table of Elements in the presence of a prepurified gas mixture of nitrogen, hydrogen and possibly a gaseous.
• hydrocarbon for example methane in a furnace in which the hard metal parts that are to be coated are heated to a temperature between 800 and 1150 C.
• the method according to the invention of producing a coating layer of metal nitride or carbonitride on hard metal parts preferably includes the pretreatment step of embedding the hard metal parts in a powder mixture of metal nitride or carbonitride to remove the sinter skin from the hard metal parts. This will ensure that the coating layer is uniformly thick on every surface of the parts during treatment in the furnace.
• a preferred procedure comprises initially moving the hard metal parts in the embedding powder mixture, for instance by rotation. This has the effect of rubbing off the sinter skin from the hard metal parts, as this might inhibit the formation of the coating layer.
• EXAMPLE 1 A stream of high temperature-dried hydrogen and nitrogen was charged with titanium tetrachloride vapour by passing the gases through a vessel filled with liquid titanium tetrachloride.
• the previously purified gas mixture was conducted over plates of hard metal consisting of 94% by weight of tungsten carbide and 6% of molybdenum in a furnace wherein the plates were heated to between 800 and 1150".
• the gas mixture reacted at the surface of the white hot hard metal plates and formed a golden yellow layer of titanium nitride.
• the adhesion of the titanium nitride layer was unexpectedly particularly good if the sinter skin was first ground or rubbed off from all faces and if the duration of the nitriding treatment was from 30 to 60 minutes. This led to the formation of a layer that was between and 50 pm. thick.
• EXAMPLE 2 For the production of a titanium carbonitride coating, the procedure of Example 1 was repeated except that the gas mixture was obtained by combining dry methane in aliquot proportions with a gas mixture of hydrogen, nitrogen and titanium tetrachloride. A coating layer containing 10% to of titanium carbide in the crystalline solid carbonitride solution was obtained.
• the colour of the layer changes from golden yellow to a reddish gold, the latter colour being attained when the composition is approximately 4TiN/1TiC.
• hard metal parts provided with golden yellow titanium nitride or red golden titanium carbonitride coating layers according to the invention may have a working life several times longer than that of uncoated plates, and from 50 to 100% longer with a correspondingly better abrasion resistance, than hard metal parts coated with titanium carbide.
• Parts treated according to the invention also have the technical advantage that the coating temperatures may be between 100 and 300 C. lower than when applying coatings of metal carbides, so that the hard metal machining parts will not undergo undesirable structural change and will not sufler an excessive decarburisation at the surface, i.e. the formation of an -phase intermediate layer.
• Suitable furnaces for performing the nitriding process are horizontal, stationary, ceramic tube kilns or also ceramic rotary kilns. In the latter type of furnace it is particularly important that the parts should be embedded in the above described manner in a powder mixture that will ensure that corners and edges of the plates are gently treated, apart from a gentle abrading eifect, i.e., removal of sinter skin.
• Other suitable furnaces are of the kind used for chromising steel and substantially have the form of a retort.
• Hard metal parts which may be treated according to the invention include machine tools, or parts of machine tools for example cutting inserts, die inserts and drawing dies.
• a machining part made from a hard metal com prising a major proportion of at least one metal carbide and a metal binder, having a surface layer consisting of a nitride of one or more metals of Groups IVa to VIa of the Periodic Table of Elements or of a carbonitride of one or more metals of Groups IVa to VIa of the Periodic Table of Elements.
• a method of producing a surface layer on a machine part made from a major proportion of at least one metal carbide and a metal binder comprising removing the outer skin of the surface of said part by embedding the part in a powder mixture of metal nitride or carbonitride and heated therein in a furnace, depositing a nitride or carbonitride surface layer on the said part at a temperature between 800 and 1150 C. by the thermal decomposition of a halide of metals of Groups IVa to VIa of the Periodic Table of Elements in the presence of a purified gas mixture of nitrogen, hydrogen, and in the case of carbonitrides, at least one gaseous hydrocarbon.
• gaseous hydrocarbon is a methane

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Vapour Deposition (AREA)
• Ceramic Products (AREA)
• Powder Metallurgy (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=5752305

Family Applications (1)

Country Status (11)

Cited By (9)

Families Citing this family (13)

Family Cites Families (8)

• 0
  • BE BE759088D patent/BE759088A/xx not_active IP Right Cessation
• 1969
  • 1969-11-28 DE DE1959690A patent/DE1959690C3/de not_active Expired
• 1970
  • 1970-10-20 CH CH1551470A patent/CH542937A/de not_active IP Right Cessation
  • 1970-10-27 AT AT963770A patent/AT318934B/de not_active IP Right Cessation
  • 1970-11-18 GB GB5488370A patent/GB1285260A/en not_active Expired
  • 1970-11-20 FR FR7041694A patent/FR2069744A5/fr not_active Expired
  • 1970-11-20 LU LU62111D patent/LU62111A1/xx unknown
  • 1970-11-27 NL NL7017392A patent/NL175534C/xx not_active IP Right Cessation
  • 1970-11-27 JP JP10474070A patent/JPS5124982B1/ja active Pending
  • 1970-11-27 SE SE1610170A patent/SE367444B/xx unknown
  • 1970-11-30 US US3717496D patent/US3717496A/en not_active Expired - Lifetime

Also Published As

Similar Documents

Legal Events