Sinter bonding of molybdenum-iron-boron cermet to steel substrate

is emphasized.

This may not be satisfactory

conventionally Processing

compacted

by shear extrusion

is evaluated

the ability to make materials texture.

It is shown that

was increased

without

in

samples. for

with controlled

electrical

resistivity

reduction

in Seebeck

coefficient.

Scaling

parameters

CVD

diamond

that

in

for growth and purity of

were investigated.

H-0.8%CH,-16.7%Ar

grown

at 40mbar

8mbar

or 400mbar.

Film

a maximum

where

showed was

found.

Growth

rate

T.Aizawa et al. (University of Tokyo, Tokyo, Japan.) J.Japnn Sot. Powder/PowderMet&, Vol 47, No J 1, 2000, 1194-J 197. In English. It is reported been

that mechanical

Te powders which

had Be-

Cutting

were hot pressed in a sin-

9%(Ni,Co)

gle step to make material electric

junction.

interface

with a p-n thermo-

Composition

was determined

microanalysis thickness.

to

determine

the

Thermoelectric

electrical

conductivity

across

by electron

the probe

junction

properties were

measured

rates.

ratio influences

of differing compositions, isostatically pressure which

ferro-

were stacked and hot

pressed. Sintering

resulted

in

was avoided

cracking

at

heating

interfaces

Materials

at 900°C

perature raised to 1200°C. two-stage

at atmospheric

by HIP.

pressurised to 200MPa the

Ba(Zr,X)O,

were

It is suggested that suppressed

interface

H.Miurn et al. (Kumamoto University Kumamoto, Japan.) J.Japan Sot. Powder/Powder Met&, Vol47, No 12, 2000, 1261.1266. In Japanese. injection

were prepared

moulding from different

with

Ti(C,N)-

was investigated cutting

by

initial pow-

edge. The

C:N

and cutin

the

of higher

properties.

indentation

tests

sub-micron

and single crystal sapphire to obtain cal-

Vicker’s hardness tests were carried out on a grades. Grain size was

were

and fitted

the

data but there were discrepancies

improved by use of high C carbonyl Fe.

of WC

data above a Vicker’s hardness starts at WC-WC

necks

that the mean length of cross-section Co necks is proportional

and

of WC-

to the WC grain size,

was derived. There was agreement model and experimental

between the

results but not with

Hard materials and tool steels

published data at high hardness.

Scaling parameters and purity of hot filament CVD diamond

Sinter bonding of molybdenum-ironboron cermet to steel substrate

V.Buck et al ( University GH Essen, Essen, Germany.) Inr. J. Refract. Metals/Hard Mater., Vol 19, No 3, 2001,169-175.

D.Rao, G.S.Upadhaya. (Indian Inst. of Technology, Kanpur, India.) PM Science/Technology Briefs, Vol2, No 4, 2000, 9-13.

www.metal-powder.net

graded

(A1203-WC/Co)-(TiC-

in 10 minutes,

current

sintering

is described.

at

The short

grain growth. Internal

Reactive sintering of titanium carbide-titanium diboride K.Kudaka et al. (Tokyo Inst. of Polytechnics, Atsuga, Japan.) J.Japan Sot. Powder/Powder Metall., Vol47, No J2, 2000, 1247-1252. In English T-B-C

Elemental

powders

were

The milled powders were reactively at 1400°C l?B2

planetary

for 10 to 40 hours at 290 to 650rpm.

ball milled

to 2000°C

composite.

sity was 97.5%

hot pressed

to synthesize

the Tic

Hardness increased with den-

sity and reduced crystallite

size. Maximum

den-

and Vicker’s hardness 25SGPa

which were attained

by 20 hours milling

and

hot pressing at 1900°C.

H.Chuanzhen et al. (Shandonmg University, Jinan, China.) PM Technology,Vol19, No 3, 2001, 153-157. In Chinese. It

is reported

materials

that

Al,O,-Sic-Ti(C,N)

had been fabricated

The material

of material

importance and process

Mechanisms

deflection

attributed

by hot pressing.

is shown to have good mechan-

ical properties.The

crack

in Co was deduced

mation

to the

electric

by pulsed

1300°C

free path

96% density. The difference

properties

compositionally

Ni),

emphasized.

of 1500. A model, assuming that plastic defor-

is attributed

of and

tionship between grain size, hardness and mean

with published

Magnetic

Production A&O,-Tic-Ni

tion

ty and had superior magnetic properties to sam-

content.

Y.Ren et al. (Osaka Uniuersiry, Jbaraki, .7apan.) J.Japan Sot. Powder/Powder Metall., Vol 47, No J 1, 2000, 12051209. In English.

0.6 to 5.0mm and %Co was 6 to 50wt%. A rela-

ples made from mixed powders that sintered to 0

features are discussed.

Microstructure and properties of alumina-silicon carbide-titanium carbonitride ceramics

Relationship between hardness grain size and mean free path of tungsten carbide-cobalt

experimental

at

Densification

studies on Al,O,

coatings on steel substrates.

ders. Pre-alloyed powder sintered to 94% densi-

lower

and microstructural

the

and may lead to

were carried out of poly-crystalline

large number of WC-Co

interface.

stresses in the materials are discussed.

Reduction

data for structural

cermet/substrate

process time prevented

S.S&dJich, AKrell. (Fraunhofer Jnst for Ceramics/Sintered Mater, Dresden, Germany.) Int. J. Refract. Metals/Hard Mater., VolJ9, No4-6, ZOOJ,237-243.

ibration

electron

was detected

wear mecha-

Hardness in sub-micron alumina and sapphire

Al,03

An Fe rich eutectic

showed lower

thermal conductivity

micro-hardness

and

Fabrication of graded alumina-titanium carbide-nickel by pulsed current sintering

S.Luyckx et al. (University of Witeoarersrand, Johannesburg, South Africa.) .) Int. J. Refract. Metals/HardMater., Vol 19, No 4-6, 2001, 245-249.

Magnetic properties of injection-moulded iron-nickel alloys

of Fe-50wt%Ni

decreased

of binder allows attainment

Recording

properties

were used to evaluate

distance.

and the tem-

diffusion.

Samples

the

of the cutting

density and mechanical

ceramics is described. Green compacts,

purity

related

temperature.

was sinter bonded to a steel sub-

microscopy

maximum

Ti(C,N)-(Ni,Co)

and

ting-edge

Use of HIP to fabricate

C-steel

Thermally

sudden failure

S.Jto et al. (Science University of Tokyo, Noda, J@n.) J.Jnpan Sot. Powder/Pow&r Metall., Vol 47, No J 1, 2000, 1210-1215. InJapanese.

probe

material.

of

nisms affect wear resistance

Fabrication of graded barium(zirconium)titanate ferroelectrics by Hip

at

curves

with two commercial

tool materials. wear

amount

electric

against

and compared

based cermet, with different vol-

Mechanical

thickness

performance

and

are discussed.

not

A.B&si et al. (Research Inst. for Ceramics Technology, Faenza, Italy.) Int. J. R&act. Metals/Hard Mater., Vol 19, No 3, 2001, 191-202.

alloying

p-type

strate.

Milling performance of titanium carbo-nitride tools against carbon steel

and n-type

used to prepare

but

A Mo,FeB, ume fractions,

is

diamond

and 200mbar

increase in filament/substrate

Production of materials with pn junctions by use of mechanical alloying

It is shown

to

of optimisaparameters

is

identified

as

Toughening

is

are

and bridging. twinning

and

dispersion

strengthening.

Intermetallic materials Structure and properties of iron aluminide made from mechanically alloyed powders K.Ozaki et al. (National Industrial Research Inst., Nagoya, Japan.) J.Japan Sot. Powder/Powder Metall., Vol47, No 12, 2000, 12.53-1257. In Japanese. Elemental

Fe-(35

were mechanically

to 50) alloyed

wt%Al

powders

in Ar, in a plane-

tary mill, for up to 100 hours. Milled powders were

pulsed-electric-current-sintered

at

MPR

41

April

2002