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Diamond and cubic boron nitride coatings for tools
method and by PM. Billets of each were extruded. The Sic particles were 5 to 10 nm in size and were uniformly distributed. Improved properties were obtained and this was attributed to increased matrix/reinforcement interface strength. It was suggested that the powder is suitable for part production and spray deposition for application of wear resistant coatings. CONSOLIDATION OF TUNGSTEN-COPPER COMPOSITES AT HIGH PRESSURE
S.H.Yoo et al. (Materials Modification, Inc, USA.) Ultrahigh-pressure sintering was used to consolidate submicron W-lO%Cu powders. Relationships between time, pressure and temperature were established by investigating each in turn. Times up to 10 minutes isothermal, pressures of 0.5 to 2.0 GPa and temperatures of 800 to 1400°C were used. Densities and structures were determined. High pressure enhanced densification. Cu migrated to the surface with abnormal grain growth.
14TI3 INTERNATIONAL PUNSEE SEMINAR. The Abstracts which follow are from papers presented at the Seminar, which was held in Reutte, Austria, in May 1997.
Hard materials !3YNTHESIS OF TUNGSTEN AND MOLYBDENUM DISILICIDES BY MECHANICALALLOYING
DIAMOND AND CUBIC BORON NITRIDE COATINGS FOR TOOLS
C.P.Klages et al. (Fraunhofer Inst., Braunschweig, Germany.) Diamond and cubic BN coatings on cutting tools were discussed with reference to problems of adhesion of coating to substrate. It was reported that this had been resolved for hardmetal and ceramic tool materials but not for coating of steel alloys for which further work was required. INTERACTIONS OF BARDMRTAL SUBSTRATES DURING DEPOSITION OF DIAMOND
B.Lux et al. (Technical University of Vienna, Vienna, Austria.) It was noted that the adhesion of diamond coatings to hardmetals is sensitive to composition of the substrate, in particular pick-up of C by low C materials. This retards deposition of diamond and weakens the interface. The problem was investigated with regard to diffusion of C into the substrate, the nature of carbides present and the depth of penetration. CU’lTING PERFORMANCE OF SUBMICRON GRAINRD TITANIUM CARBONITRIDE CERMETS
E.I.Ivanov, E.J.Schapker. (Tosoh SMD Inc, Grove City, Ohio, USA.) MA of W-Si and Mo-Si powders was investigated. A W container and balls were used for the W-Si and hardened steel for Mo-Si. W-Si first formed a nanoscale mixture with a grain size of 10 nm. WSi, or MoSi, were formed on heating or prolonged milling. Differential scanning calorimetry was used to investigate the stability of the compounds. The powders were consolidated by HIP. The materials were used as targets. Sputtering from the targets was reduced by diminished grain size. NOVEL PM TECHNIQUES FOR REFRACTORY METALS AND BARD MATERIALS
R.M.German. (Pennsylvania University, Pennsylvania, USA.)
The use of injection moulding technology, for refractory metals and hard materials, was discussed. Feedstocks with large proportions of solid and small amounts of binder are moulded. The powders need to be de-agglomerated and of a size to suit the process. The mouldings are debound and sintered. The paper discussed the process with regard to powder characteristics, applications and properties of sintered parts.
State
T.Tanase et al. (Mitsubishi Materials Corp, Ibaraki-Ken, Japan.) Cutting tools made from Ti(C,N) based cermets were reviewed. Inferior toughness compared with cemented carbides was noted. It was reported that a submicron grade of Ti(C,N), with improved toughness and wear properties, had been developed. The cutting performance was discussed in relationship with properties and microstructure. MACHINING TESTS ON MULTI-LAYER COATED CEMENTBD CARBIDE CU’I”l’INGTOOLS
M.Larrson et al. (Uppsala University, Uppsala, Sweden.) It was reported that face milling tests, on steel, had been used to evalu-
ate cutting tools with multi-layer Ti/TiN and TiN/NbN coatings. Coating techniques were outlined. The coatings had Vicker’s microhardnesses of 2400 for TQl’iN, and 3200 for TiN/NbN. Cutting performance of multi-layer TiN/NbN coated tools was superior to single layer coated tools. CONTROL OF DISTORTION DURING LIQUID PIIASE SINTERING
R.M.German, A.Upadhyaya. University, (Pennsylvania State Pennsylvania, USA.) The effects of structure and solubility parameters on distortion during LPS W-Ni-Fe, were investigated on W-Ni-Cu, Fe-Cu and MO-Cu. Distortion was monitored in real time. Where there is solid solubility there is a major change in solubility at the onset of melting and this promotes dissolution of the solid structure. Fe-Cu showed marked loss of rigidity. With low solid solubility and a high solid content, such as MO-Cu, the skeletal structure resists slumping during sintering. A model is suggested to predict rigidity.
Coatings EFFECT OF PLASMAETCHING ON ADHESION STRENGTH OF DIAMOND FILM
Z.Kesong et al. (Guangzhou Research Metals, Inst. of Non-Ferrous Guangzhou, China.) The adhesion of diamond films to cemented carbide substrates was investigated with regard to preparation of the substrate surface before deposition. It was reported that etching of the substrate by plasma arc sputtering roughens the surface and changes the surface composition to pure W. Adhesion is improved when the decarburized surface is recarburized during deposition of diamond. IN SZTUCHEMICALVAPOUR DEPOSITION OF CUBIC BORON NITRIDE
I.Konyashin et al. (Max-Planck Inst. fur Metallforschung, Stuttgart, Germany.) Reactions between hybridized BN with H plasma were presented. Deposition of BN and BCN films by decomposition in situ of B-N-H and B-C-N-H precursors, with radio frequency and microwave plasma was investigated. Deposits of cubic BN were free of non-cubic forms when synthesized using plasma assisted CVD. A mechanism is proposed.
MPR December 1997 45
S.H.Yoo et al. (Materials Modification, Inc, USA.) Ultrahigh-pressure sintering was used to consolidate submicron W-lO%Cu powders. Relationships between time, pressure and temperature were established by investigating each in turn. Times up to 10 minutes isothermal, pressures of 0.5 to 2.0 GPa and temperatures of 800 to 1400°C were used. Densities and structures were determined. High pressure enhanced densification. Cu migrated to the surface with abnormal grain growth.
14TI3 INTERNATIONAL PUNSEE SEMINAR. The Abstracts which follow are from papers presented at the Seminar, which was held in Reutte, Austria, in May 1997.
Hard materials !3YNTHESIS OF TUNGSTEN AND MOLYBDENUM DISILICIDES BY MECHANICALALLOYING
DIAMOND AND CUBIC BORON NITRIDE COATINGS FOR TOOLS
C.P.Klages et al. (Fraunhofer Inst., Braunschweig, Germany.) Diamond and cubic BN coatings on cutting tools were discussed with reference to problems of adhesion of coating to substrate. It was reported that this had been resolved for hardmetal and ceramic tool materials but not for coating of steel alloys for which further work was required. INTERACTIONS OF BARDMRTAL SUBSTRATES DURING DEPOSITION OF DIAMOND
B.Lux et al. (Technical University of Vienna, Vienna, Austria.) It was noted that the adhesion of diamond coatings to hardmetals is sensitive to composition of the substrate, in particular pick-up of C by low C materials. This retards deposition of diamond and weakens the interface. The problem was investigated with regard to diffusion of C into the substrate, the nature of carbides present and the depth of penetration. CU’lTING PERFORMANCE OF SUBMICRON GRAINRD TITANIUM CARBONITRIDE CERMETS
E.I.Ivanov, E.J.Schapker. (Tosoh SMD Inc, Grove City, Ohio, USA.) MA of W-Si and Mo-Si powders was investigated. A W container and balls were used for the W-Si and hardened steel for Mo-Si. W-Si first formed a nanoscale mixture with a grain size of 10 nm. WSi, or MoSi, were formed on heating or prolonged milling. Differential scanning calorimetry was used to investigate the stability of the compounds. The powders were consolidated by HIP. The materials were used as targets. Sputtering from the targets was reduced by diminished grain size. NOVEL PM TECHNIQUES FOR REFRACTORY METALS AND BARD MATERIALS
R.M.German. (Pennsylvania University, Pennsylvania, USA.)
The use of injection moulding technology, for refractory metals and hard materials, was discussed. Feedstocks with large proportions of solid and small amounts of binder are moulded. The powders need to be de-agglomerated and of a size to suit the process. The mouldings are debound and sintered. The paper discussed the process with regard to powder characteristics, applications and properties of sintered parts.
State
T.Tanase et al. (Mitsubishi Materials Corp, Ibaraki-Ken, Japan.) Cutting tools made from Ti(C,N) based cermets were reviewed. Inferior toughness compared with cemented carbides was noted. It was reported that a submicron grade of Ti(C,N), with improved toughness and wear properties, had been developed. The cutting performance was discussed in relationship with properties and microstructure. MACHINING TESTS ON MULTI-LAYER COATED CEMENTBD CARBIDE CU’I”l’INGTOOLS
M.Larrson et al. (Uppsala University, Uppsala, Sweden.) It was reported that face milling tests, on steel, had been used to evalu-
ate cutting tools with multi-layer Ti/TiN and TiN/NbN coatings. Coating techniques were outlined. The coatings had Vicker’s microhardnesses of 2400 for TQl’iN, and 3200 for TiN/NbN. Cutting performance of multi-layer TiN/NbN coated tools was superior to single layer coated tools. CONTROL OF DISTORTION DURING LIQUID PIIASE SINTERING
R.M.German, A.Upadhyaya. University, (Pennsylvania State Pennsylvania, USA.) The effects of structure and solubility parameters on distortion during LPS W-Ni-Fe, were investigated on W-Ni-Cu, Fe-Cu and MO-Cu. Distortion was monitored in real time. Where there is solid solubility there is a major change in solubility at the onset of melting and this promotes dissolution of the solid structure. Fe-Cu showed marked loss of rigidity. With low solid solubility and a high solid content, such as MO-Cu, the skeletal structure resists slumping during sintering. A model is suggested to predict rigidity.
Coatings EFFECT OF PLASMAETCHING ON ADHESION STRENGTH OF DIAMOND FILM
Z.Kesong et al. (Guangzhou Research Metals, Inst. of Non-Ferrous Guangzhou, China.) The adhesion of diamond films to cemented carbide substrates was investigated with regard to preparation of the substrate surface before deposition. It was reported that etching of the substrate by plasma arc sputtering roughens the surface and changes the surface composition to pure W. Adhesion is improved when the decarburized surface is recarburized during deposition of diamond. IN SZTUCHEMICALVAPOUR DEPOSITION OF CUBIC BORON NITRIDE
I.Konyashin et al. (Max-Planck Inst. fur Metallforschung, Stuttgart, Germany.) Reactions between hybridized BN with H plasma were presented. Deposition of BN and BCN films by decomposition in situ of B-N-H and B-C-N-H precursors, with radio frequency and microwave plasma was investigated. Deposits of cubic BN were free of non-cubic forms when synthesized using plasma assisted CVD. A mechanism is proposed.
MPR December 1997 45