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Preparation of sintered iron nitride compacts
above this. A glass transition temperature of 473°C was measured by differential thermal analysis. Vicker’s hardness was 215-155.
Berylium Trends in powder processing berylium alloys W.J.Haws. (Brush Wellman Inc., (JOM), Voi 52, No 5, 2000, 35-37.
USA.) J .Metals
Numerous applications of Be based alloys are discussed with regard to properties and production by PM technology. It is reported that developments in recent years have been in an effort to reduce costs of Be parts, which are expensive.
Cobalt Stabilisation of high temperature phase in ultradispersed cobalt powder V.V.Lwina CCal. Russian Metaliurgy, No 3, 1999, 102-
105.In Enylrsh. Phase composition and structure of fine Co powders, made by H reduction of Co hydroxides, were investigated by X-ray diffraction. The face-centred-cubic high temperature phase was found to be stabilised at amhient temperature. The lattice parameter of the fine powder was shown to he smaller than in bulk metal. There was some distortion of the lattice.
Preparation of sintered iron nitride compacts K.Tanakn, K.Hayashi. jllniwrsiry of Tokyo, .Jnpan .) J.Japan Sot. Powder/Powder Me&., Vol 47, No 6, 2000, 600-606. In English
Green and sintered Fe compacts, with densities of 70 to 90%, were nitrided in NH3-50vol%H2 at 650°C for 1 to 4 hours. After 4 hours the samples were almost completely nitrided and densities were 76-77%. This was attributed to expansion and cracking, in sintered specimens. Magnetic saturation was 80% of high density Fe.
Nickel Inclusions in nickel base superalloy WJianrm et ai. (Cennai iron and Steel inst., Beijing,China.) PM Technology, Vol 19, No I, 2001, 3-6. Jn Chinese.
Inclusions in a Ni base superalloy powder, made by plasma rotating electrode process, were characterised for inclusion content in the powder, type, size and shape. Effects of treatment to remove inclusions from the powder, and methods of reducing initial inclusion content are discussed.
Characteristics and quality control of inclusions in PM Materials,
Beijing, China.) PM Technology, Vol 19, No I, 2001, 7, 11.In Ckmese.
www.metal-powder.net
Young’s modulus of 195GPa, bend strength of 509MPa and maximum strain of 5%. Lower values were found with lower amounts of reinforcement. Comparison is made with materials made by other techniques.
Ceramic materials
Electrical and magnetic materials
Tensile strength of ceramic powder compacts
Materials used in production of electrical contacts
KYanai,
S.Ksiezmk,
M.Hrai.
(Japan Nuclear
Fuels Co. Ltd.,
ibarakt, Japan.) J.Japan Sec. Powder/Powder Metall., Vol 47, No 6, 2000, 591,599. In English
Tensile strengths of green Al,O, compacts were measured to relate strength to powder packing structure. In absence of agglomerated particles, powder particle size, porosity and mean pore size were correlated with strength, For spheroidal powders with small pores tensile strength was high. Presence of agglomerated particles reduced tensile strength.
Composite materials Processing and consolidation of particle-reinforced metal-matrix composites J.M.T.CarreU
et al. (University Carlos III, Madrid,
Spam.) Revista Merail. Madrrd, Voi 36, No 3, 2000, 193.197. In Sjmxsh.
Iron and steel
Z.finwen, W.Wuxiang. (inst. of Aeronnmcai
Effects of inclusions on fracture of PM Ni base superalloy are discussed. Nature and sources of inclusions and deformation of inclusions during deformation processing are considered. Methods for control of inclusions are indicated.
Forming and consolidation methods for particle reinforced metal matrix composites were reviewed. Two situations, forming from raw materials and consolidation of preforms are considered.
Carburisation of metal oxides dispersed in resin
It is reported that B and Ti carbides had been synthesized by heating metal oxide-resin composites at temperatures above 2000°C. On heating the resin decomposed and graphitised. The oxides were reduced to metal and carburised. A TiO2-(30 to 35)wt% resin composite, heated at 2000 to 2250°C produced a porous sintered Tic material with a bend strength of about 70MPa.
Application of hot pressing to production of metal matrix composites C.F.Feng, J.Froyen. (Kntholic University Leuvcn, Beigmm.) PM Jrtdustry, Vol JO, No 5, 2000, 7.14. In Chinese.
Reactive sintering in production of particlereinforced metal matrix composites is reviewed. It is reported that the method had been used to make Al-AI,O,-TiB, from AlTiO,-B powder mixtures by hot pressing. AllOvol%Al,O,-9%TiB, is shown to have a
B.Bes:tak.
Wm J. lnt.,
Vof 33, No 4,
2000,208-213 It is reported that PM techniques had been used to make composite AgSnOz-BizOi materials for use in electric contact applications, to avoid use of toxic Cd, The new material is shown to be superior to AgCdO alloys in switching currents up to lOOOA, dc and ac.
Mechano-synthesis of zinc ferrite from zinc oxide and aferric oxide W.Km, F.&m. (Tohoktc Uniwrscty, Sendni, Japan.) Powder Technoi., Voi 114, No f-3, 2OOl,12-16.
Production of Zn ferrite, ZnFe,O,, from ZnO and FeZOJ, by planetary milling, at ambient temperature, is described. Amorphous ferrite was made after 2 hours. Extending milling time by 2 to 3 hours produced nanocrystalline powders.
Hard materials and tool steels Effect of chromium and vanadium on magnetic properties and grain size of cemented carbides S.Ha&nd, S.Sundm, (Inst. for Metals Research, Stockholm, Sweden.) Jnt. 1. Rej‘iracMetals/Hard Mater., Vol 18, No 6, 2000, 297-300. It is noted that magnetic properties of hardmetals may he used as an indirect measure of structure and models relating grain size to coercive force have been developed. A study of the effect of grain growth inhibitors, Cr and V, on magnetic properties of WC-Co is described. It is shown that O.Zwt%V and 0.4’Kr have different effects but nevertheless models for magnetic properties and grain size could be applied.
Trends and market perspectives for diamond tools in construction industries W.Tillmann. iHdrl AG, Schnan, L~echtemrein.) Jnt. J. Refrnc.Merals/Hard Mater., Vi,/ 18, No 6, 2000, 301306.
Applications for diamond in cutting tools are discussed with regard to properties. The current status of diamond technology is reviewed with emphasis on applications in construction industries, corresponding market trends and the role of PM and coating technologies in satisfying industrial needs.
MPR December
2001
37
Berylium Trends in powder processing berylium alloys W.J.Haws. (Brush Wellman Inc., (JOM), Voi 52, No 5, 2000, 35-37.
USA.) J .Metals
Numerous applications of Be based alloys are discussed with regard to properties and production by PM technology. It is reported that developments in recent years have been in an effort to reduce costs of Be parts, which are expensive.
Cobalt Stabilisation of high temperature phase in ultradispersed cobalt powder V.V.Lwina CCal. Russian Metaliurgy, No 3, 1999, 102-
105.In Enylrsh. Phase composition and structure of fine Co powders, made by H reduction of Co hydroxides, were investigated by X-ray diffraction. The face-centred-cubic high temperature phase was found to be stabilised at amhient temperature. The lattice parameter of the fine powder was shown to he smaller than in bulk metal. There was some distortion of the lattice.
Preparation of sintered iron nitride compacts K.Tanakn, K.Hayashi. jllniwrsiry of Tokyo, .Jnpan .) J.Japan Sot. Powder/Powder Me&., Vol 47, No 6, 2000, 600-606. In English
Green and sintered Fe compacts, with densities of 70 to 90%, were nitrided in NH3-50vol%H2 at 650°C for 1 to 4 hours. After 4 hours the samples were almost completely nitrided and densities were 76-77%. This was attributed to expansion and cracking, in sintered specimens. Magnetic saturation was 80% of high density Fe.
Nickel Inclusions in nickel base superalloy WJianrm et ai. (Cennai iron and Steel inst., Beijing,China.) PM Technology, Vol 19, No I, 2001, 3-6. Jn Chinese.
Inclusions in a Ni base superalloy powder, made by plasma rotating electrode process, were characterised for inclusion content in the powder, type, size and shape. Effects of treatment to remove inclusions from the powder, and methods of reducing initial inclusion content are discussed.
Characteristics and quality control of inclusions in PM Materials,
Beijing, China.) PM Technology, Vol 19, No I, 2001, 7, 11.In Ckmese.
www.metal-powder.net
Young’s modulus of 195GPa, bend strength of 509MPa and maximum strain of 5%. Lower values were found with lower amounts of reinforcement. Comparison is made with materials made by other techniques.
Ceramic materials
Electrical and magnetic materials
Tensile strength of ceramic powder compacts
Materials used in production of electrical contacts
KYanai,
S.Ksiezmk,
M.Hrai.
(Japan Nuclear
Fuels Co. Ltd.,
ibarakt, Japan.) J.Japan Sec. Powder/Powder Metall., Vol 47, No 6, 2000, 591,599. In English
Tensile strengths of green Al,O, compacts were measured to relate strength to powder packing structure. In absence of agglomerated particles, powder particle size, porosity and mean pore size were correlated with strength, For spheroidal powders with small pores tensile strength was high. Presence of agglomerated particles reduced tensile strength.
Composite materials Processing and consolidation of particle-reinforced metal-matrix composites J.M.T.CarreU
et al. (University Carlos III, Madrid,
Spam.) Revista Merail. Madrrd, Voi 36, No 3, 2000, 193.197. In Sjmxsh.
Iron and steel
Z.finwen, W.Wuxiang. (inst. of Aeronnmcai
Effects of inclusions on fracture of PM Ni base superalloy are discussed. Nature and sources of inclusions and deformation of inclusions during deformation processing are considered. Methods for control of inclusions are indicated.
Forming and consolidation methods for particle reinforced metal matrix composites were reviewed. Two situations, forming from raw materials and consolidation of preforms are considered.
Carburisation of metal oxides dispersed in resin
It is reported that B and Ti carbides had been synthesized by heating metal oxide-resin composites at temperatures above 2000°C. On heating the resin decomposed and graphitised. The oxides were reduced to metal and carburised. A TiO2-(30 to 35)wt% resin composite, heated at 2000 to 2250°C produced a porous sintered Tic material with a bend strength of about 70MPa.
Application of hot pressing to production of metal matrix composites C.F.Feng, J.Froyen. (Kntholic University Leuvcn, Beigmm.) PM Jrtdustry, Vol JO, No 5, 2000, 7.14. In Chinese.
Reactive sintering in production of particlereinforced metal matrix composites is reviewed. It is reported that the method had been used to make Al-AI,O,-TiB, from AlTiO,-B powder mixtures by hot pressing. AllOvol%Al,O,-9%TiB, is shown to have a
B.Bes:tak.
Wm J. lnt.,
Vof 33, No 4,
2000,208-213 It is reported that PM techniques had been used to make composite AgSnOz-BizOi materials for use in electric contact applications, to avoid use of toxic Cd, The new material is shown to be superior to AgCdO alloys in switching currents up to lOOOA, dc and ac.
Mechano-synthesis of zinc ferrite from zinc oxide and aferric oxide W.Km, F.&m. (Tohoktc Uniwrscty, Sendni, Japan.) Powder Technoi., Voi 114, No f-3, 2OOl,12-16.
Production of Zn ferrite, ZnFe,O,, from ZnO and FeZOJ, by planetary milling, at ambient temperature, is described. Amorphous ferrite was made after 2 hours. Extending milling time by 2 to 3 hours produced nanocrystalline powders.
Hard materials and tool steels Effect of chromium and vanadium on magnetic properties and grain size of cemented carbides S.Ha&nd, S.Sundm, (Inst. for Metals Research, Stockholm, Sweden.) Jnt. 1. Rej‘iracMetals/Hard Mater., Vol 18, No 6, 2000, 297-300. It is noted that magnetic properties of hardmetals may he used as an indirect measure of structure and models relating grain size to coercive force have been developed. A study of the effect of grain growth inhibitors, Cr and V, on magnetic properties of WC-Co is described. It is shown that O.Zwt%V and 0.4’Kr have different effects but nevertheless models for magnetic properties and grain size could be applied.
Trends and market perspectives for diamond tools in construction industries W.Tillmann. iHdrl AG, Schnan, L~echtemrein.) Jnt. J. Refrnc.Merals/Hard Mater., Vi,/ 18, No 6, 2000, 301306.
Applications for diamond in cutting tools are discussed with regard to properties. The current status of diamond technology is reviewed with emphasis on applications in construction industries, corresponding market trends and the role of PM and coating technologies in satisfying industrial needs.
MPR December
2001
37