Preparation of submicron nickel powder by ultrasonic spray pyrolysis

Powder production

atomization are established in production.

PREPARATION OF SUBMICRON NICKEL POWDER BY ULTRASONIC SPRAY PYROLYSIS

LASER SYNTHESIS OF ULTRAFINE ALUMINA POWDERS

S. Stopic et al. (Serbian Academy of Sciences and Arts, Belgrade, Yugoslavia). Int. J. Powder Metall., Vol 32, No 1, 1996, 59-65. It is reported that submicron Ni powder has been produced by ultrasonic spray pyrolysis of an aqueous solution of Ni chloride and nitrate followed by thermal decomposition of the aerosol in N-H. The conditions are described and it is shown that particle size can be controlled by process conditions. Particles were nearspherical and non-agglomerated. SPLATTING

AND SOLIDIFICATION

OF

PLASMA SPRAYED METAL POWDERS IMPINGING ON STAINLESS STEEL M. Fukumoto et al. (Toyohashi University of Technology, Toyohashi, Japan) _ f. Japan Znst. Metals, Vol 59, No 11, 1995, 117% 1184. (In Japanese.) Studies on the effect of substrate temperature and particle material on solidification and splat behaviour of powder sprayed onto stainless steel are described. In some cases there was splashing on impingement on the substrate at 25°C. This is attributed to rapid solidification with surface tension being a controlling factor. METAL FIBRE PRODUCTION POWDER EXTRUSION

of AlzOs powders intensity reported

5-10

pm by

Z. Maiqun et al. (Xian University of Science and Engineering, Xian, China). PM Technol., Vol 13, No 4, 1995, 268-270. (In Chinese.) Investigations of factors affecting atomization of Al, negative pressure at nozzle tip and construction materials, are outlined. Conditions for efficient

1996

Laser

affect

phase

conditions

intensity,

500

are

W;

and

l-10 kPa in He.

PRODUCTION OF IIAFNIUM AND ZIRCONIUM POWDERS BY FUSED ELECTROLYSIS

SALT

J. Sehra et al. (Bhaba Atomic Research Centre, India). High Temp. Mater. Proc., Vol 14, No 2, 1995, 115120. It is reported produced

that Zr and Hf have been

from

recycled

metals

by

electrolysis. The process is reported to be optimized for product purity and yield, and the

powders

quality.

are

shown

Electrolytic

to

be

processing

of

good

of zircalloy

is outlined.

Pressing PRESS TOOLS FOR PRODUCTION BLANKS BY RADIAL EXTRUSION

OF

S.M. Vaitsekhovich. Poroshkovaya Metallurgiya, No l/2, 1995, 110-118. (In Russian.) and testing

compaction

production

are

of short

reported. billets

system

Tools

for

included.

Sintering COMPUTER MODELLING AND DESIGN OF SINTERING ATMOSPHERES T. Philips et al. (Airco/BOC Gases). Mater. Australasia, Vol 27, No 4, 1995, 14-16. Atmosphere zoning in sintering furnaces is discussed with regard to gas composition, rates

and

metallurgical modelling understanding

process

validated

optimization

requirements. used to is of

flow

behaviour. Computational was used to study variables

ANALYSIS OF THE ORIGIN OF POROSITY IN COMBUSTION SYNTHESIZED MATERIAL Z.A. Munir

(University

of California,

USA).

J. Mater. Synthesis Proc., Vol 1, No 6, 1994, 387-394. Origins of porosity in materials made by combustion synthesis are identified and analyzed. These are changes in molar volume during reaction, gas evolution from volatile impurities, thermal migration caused by temperture gradients and pre-existing pores. The contributions of each are discussed and examples given.

Aluminium SINTERING OF MIXED COPPER-LEAD ALLOYS

ALUMINIUM-

in two stages,

for production of long billets by three stage compaction and plain short prisms are

flow

J.J. Park (Hong-Ik University, Seoul, South Korea). ht. J. Mech. Sci., Vol 37, No 7, 1995, 709-719. Yield criteria for sintered metals are compared and one was modified to derive relationships for plastic deformation in compression. Three coefficients were used, two interdependent and functions of Poisson’s ratio of the material. The other is independent of the material. A proceedure to calculate flow stress is outlined. Verification was carried out for 2024Al powders and Fe-36%Ni and good agreement is reported.

of a range of

devices which use an equal channel

FACTORS INFLUENCING ATOMIZATION OF ALUMINIUM

MPR September

be:

Development

Vol 33, No 7, 1995, 928-933. (In Korean.) Metal powder extrusion for production of fibres is reported. The method is shown to have advantages over other methods in that fibres less than 10 pm with controlled shape can be made. Ag fibres 2 ,um by

34

to

Optimum to

pressure,

have been studied.

shown

composition.

BY

D.I. Kim et al. (Kunsan National University, Kunsan, Korea). J. Korean Inst. Metals,

libres

is

Fundamentals CONSTITUTIVE RELATIONS TO PREDICT DEFORMATION OF POROUS METALS IN COMPACTION

V.N. Antsiferov et al. Poroshkovaya Metallurgiya, No l/2, 1995, 1-4. (In Russian.) Laser synthesis, structure and properties

of

30 mm long and Al 1-3 mm were made.

and validated

and

for

Numerical increase

D. Nath et al. (Benares Hindu University, India). nuns. Indian Inst. Metals, Vol 48, No 2, 1995, 63-68. Sintering behavior of Al-4.5wt%Cu15%Pb, from blended powders, pressed at 98, 196, 294 or 392 MPa and sintered at 520, 560 or 600°C in N, was investigated with regard to density, porosity and hardness. Increase in pressure increased densification more than increased temperature. Volume changes are described. The presence of a liquid phase is deduced. INFLUENCE

OF COPPER

ON

PROPERTIES OF ALUMINIUMALUMINA COMPOSITE MATERIALS

thermal

fluid dynamics and the results

and used for system design

W. Julin et al. (Qinghua University, Beijing, China). PM Techn.ol., Vol 13, No 4, 1995, 271-275.

(In Chinese.)