Y. Kai et al. (Nippon Tungsten Co., Fukouka, Japan). Nippon Tungsten Rev., Vol 27, 1995, 10-17. Production of W- (10 to 40) %Cu parts, to close dimensional tolerances, by liquid phase sintering or Cu infiltration was investigated. It is reported that parts could be made in W-(15 to 27)YKu with minimal shrinkage from a blend of 1 and 8 urn powder and infiltration.
Hard materials and too/ steels A HISTORY OF FINE-GRAINED HARDMETALS G.E. Spriggs (Rusheen, Castlemain, Ireland). Znt. J. Refi-uctory Metals and Hard Muteriuls, Vol 13, No 5, 1995, 241. 255. The scientific and technological development of fine-grained hardmetals historically
reviewed. 1929 is noted as the
year of identification
Electrical and magnetic ma teriak
the particle size which can be produced. The role of milling is discussed with reference to uniformity of compacts and inhibition of grain growth during sintering
of some aspects of WC
grain refinement and by 1939 the beneficial grain relining effects of VC and TaC had been established. Changes in the definition
A TECHNICAL ECONOMIC ANALYSIS OF MAGNETS AND MAGNETIC MATERIALS
of ‘fine’ are considered, going from pm sizes in early years to nm sizes more recently. The author asks if this is the end of the story.
Norwalk, Connecticut, USA). Int. J. Powder Metullurgy, Vol 31, No 2, 1995, 133-136. The commercial magnetic magnet
CARBIDE BASED CARBIDES
status of hard and soft
materials is reviewed. Permanent alloys
L.J. Prakash (PM Pulvermetall GmbH, Rottenburg, Germany). Znt. J. Refructory Me-
ferrites, Sm-Co, Fe-Nd-B and Alnico. Soft materials were Fe-% electrical steels,
tals und Hard
It is noted that sub-micron grade cemented carbides account for 10.15% of
It is considered
alloys and Fe-Ni.
further improvements numerous applications will be found.
the market being characterized
of Science, Beijing,
PM Technology, Vol 13, No 1, 1995,
3-7. (In Chinese.) It is reported that Ar atomized Fe-Nd-B powder consisted of a tetragonal NdzFe,,B phase. The compared
magnetic properties with powder made
of cast material
MECHANISM OF IMPROVEMENT CORROSION RESISTANCE OF TERNARY NEODYMIUM-BORON
CARBIDE ON TO NODULAR CAST IRON BY HOT ISOSTATIC PRESSING C. Feixiong,
Steel Research Inst., Beijing, China). PM Technology, Vol 13, No 1, 1995, S-13. (In Chinese.) reported of
At pH above 5.8 by a passive film.
performance described. modulus
It is reported is a controlling
factor in bonding.
IMAGING AND MODELS GRAINED HARDMETALS B. Roebuck Teddington,
PROPERTIES FOR FINE-
(National Physical Laboratory, Middlesex, UK). Znt. J. Kefiac-
tory Metals and Hard Materials, Vol 13, No 5, 1995, 265-279. The hardness of WC hardmetals, particle
improvements in the technology of testing and characterization are required. These issues and models for prediction of hardness and magnetic properties from grain size are considered,
relationship in particular. The use coercivity measurements for estimation
regard to the need for standardization
for grain size measurement. OF BORON CARBIDE
S.M. Joo et al. (Chungnam
tory Metals and Hard Materials, Vol 13, No 5, 1995, 281-296. Aspects and liquid
of powder production, milling phase sintering of WC based
Synthesis of B,C was investigated a11(1is shown to be possible by reacting :! 1i;ir.l~
BzO:r, 6 to 7 parts Mg and 1 to 1.4 parts 01’ C. The B,C particles are showu IO I),* spherical and pure. ParticI(b si/.cb is
to be more effective than Co against pitting.
that 50-150 nm represents
versity, Daejeon, Korea). J. Korean Ztrsl. u/’ Metals, Vol 32, No 10, 1994, 1243-1249. (III Korean.)
Keplacement of Fe by Ni and Co enhances corrosion resistance at pH2.7. Ni is shown
FROM OXIDE BY SELF-PROPAGATING HIGH TEMPERATURE SYNTHESIS
W.D. Schubert et al. (Technical University of Vienna, Vienna, Austria). Znt. J. Refiuc-
cutting performance. Investigations of mechanical properties and cutting
ASPECTS AND LIMITS OF ULTRAFINE TUNGSTEN CARBIDE POWDER AND
Ni-Ti) -B magnets had been elucidated with some improvements made. These are attributed to small differences in of pH2.7. is inhibited
with the is and
matrix in cutting tool materials discussed with respect to physical
It is reported that the mechanism of corrosion resistance of sintered Nd- (Fe-Co-
449-453. (In Japanese.) Bonding of diamond
T. Fujimori et al. (Chiba Inst. of Technology, Narashino, Japan). J. Japan Sot. Powder and Powder Metallurgy, Vol 41, No 4, 1994,
nodular cast iron had been achieved by HIP using Ni foil as an interlayer. Interface strength and evaluated.
OF THE MATRIX
CUTTING PROPERTIES DL4MOND TOOLS
J. Japan Inst.
ofMetals, Vol 59, No 2, 1995, 206-212. Japanese.)
to result in
service lives of components.
MAGNETS Y. Fukuda, M. Shimotomai
by a balance
to use is reported
13, No 5,
materials as well as forming tools and in wear resistant applications. Matching
0. Tong et al. (Academy
between hardness and toughness. The materials are used for cutting a wide range of metallic and non-metallic
MICROSTRUCTURE AND HARD MAGNETIC PROPERTIES OF ATOMIZED POWDER
by addition of VC. Grain growth in the solid state is considered. Discontinuous grain growth in ultraline materials is noted. It is suggested that there is a lower limit of ZOO-300 nm for the grain size of WC and that finer sizes can only be attained by completely new technology.
It is suggested a lower limit to
reduced by increased