Corrosion of tungsten carbide-nickel-chromium in sodium hydroxide solution

by

hot

pressing.

diamond/matrix

Weak

bonds

and

strong

were identified.

weak bonds were due to incomplete

Some

sintering.

Y.Haya.shi et al. (Kywhu University, Japan.) Nippon Tungsten Rev., Vol 32, 2000, 17-29

Effect of test procedures on evaluation of fracture toughness

Corrosion

relationship

WC-Co

of fracture

to test method

four test types. Fracture compared

toughness

was investigated toughness

and discussed.

of

tensile

stresses,

Single-edge

introduced

ing, are relieved.

for

notched

fracture

where

during

This opinion

mechanics

analysis

in T’-2Gwt%Mo-33%TiC

was investigated

XC

in acid solutions

by electrochemical

sion tests. The corrosion 10 times that in 35%HCl.

was

and it is deduced that

this was due to chemical weH as electrochemical

and immer-

rate in 5%HNO, decomposition

residual

pre-crack-

is supported

by

and fractographic

Dimensional

changes during sintering of WC-

8%(Ni,Fe),

made

1Smm

powders with or without

of

WC

VC,

were

Sintering 1150°C

200nm

investigated

expansion

der. Most

from

marked

by

to 300nm

or

additions

dilatometry.

was lower for the mm pow) shrinkage

was at 800°C

or

for the nm or mm powder respectively.

Increase in %C reduced the temperature shrinkage.

With constant

for rapid

initial density, shrink-

age increased with increase in temperature.

was

reaction.

values were

bend and surface crack in flexure tests are suggested to be the most reliable

of XC

and non-stoichiometric

L.LIanes et al. (Polytechnic University of Catalunya, Barcelona, Spain.) Int. J.Refratory Metals/Hard/Mater., VoJ 19, No 1, 2001, 27-34. The

Corrosion of titanium carbide in acid solutions

Sintering shrinkage in nano-crystalline cemented carbides L.Y.Zhmg et al. (University of Science and Technolom, Beijing, China.) PM Industry, Vol JO, No 5, 2000, J52 J In Chinese.

Hot isostatic pressing of as-sintered cemented carbides Z.C.Jia. (Central Iron B Steel Research Inst., Beijing, China.) PM Industry, Vol JO, No 5, 2000, 23-25. In Chinese. Doubt

is expressed

measurement

about the use of density

to estimate

porosity of cemented

examination.

Effect of electro-discharge machining on sliding contact of cemented carbides L.Llaneset al.

(Polytechnic Unwenity of Catalunya, Barcelona, $ain.) Jnt. J.Refractory Met&/Hard/Mater., Vol 19, No 1,2cJOI, 35-40. Correlation machining

between

and surface

wear of fine-grain with

WC-Co

regard to surface

electron

microscopy.

discrimination

and effect

in the

of

were investigated

finish,

using scanning

The method

of EDM

are discussed

electro,discharge

integrity

used allowed

defects.

light

The

findings

of surface

damage

related to surface finish.

Shallow cracks on the surface of cemented carbide M.Kanetn et al. (Kyuhu Inst. of Technology, Japan.) Nippon Tungsten Reu., Vol 32, 2000, J-7. Shallow

cracks

cemented Sic

or Si,N,

cracks

but

only

increased

on

methods

mechanisms.

did not

occur

cermets.

as binder

were more readily

surfaces

investigated

materials.

element

possible

that

were

as counter

results by finite identify

on the rubbing

carbides

Analysis

content

of

was used to It is reported

on ceramic

Inter-crack

induced

of

using

alone

distance

increased. by Si,N4

Cracks than

by

Sic.

Corrosion of tungsten carbide-nickel-chromium hydroxide solution

in sodium

Y.Hnyashi et al. (Kyushu Uniwrsity, Japan.) Nippon Tungsten Rev., Vol32, 2000, 8-16 Resistance investigated tests.

to corrosion

of WC-NiCr

by immersion

It is reported

and

that corrosion

was

polarisation resistance

in

acid and neutral solutions

is improved by low C

and high Cr,C,

InN NaOH

the corrosion

contents.

rate was higher

higher for high Cr,C,

contents.

and

In the immer-

sion tests most of the dissolved material

www.metal-powder.net

solution

for low C

was W.

MPR June

2002

57