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Study on the physical and mechanical properties of nibased sintered metallic foams

E. BRUJ1,* , N. JUMATE1, I. VIDA-SIMITI1, V. MOLDOVAN1, D. NEMEŞ1

Affiliation

  1. Department of Materials Science and Technology, Technical University of Cluj-Napoca, 103-105 Muncii Ave., 400641 Cluj-Napoca, Romania

Abstract

This paper aims at studying the possibility of achieving foam structures (open and closed porosities), with low densities by powder metallurgy route using space holders [1-3]. Hollow spherical 125 to 400 µm particles of NiCrSiB powders obtained through argon gas atomization and polystyrene particles (as space holders) were used. The obtained mixture was homogenized for 10 minutes together with an organic binder. The organic binder used was polyvinyl alcohol (PVA), a hydrophilic synthetic polymer soluble in water, with a melting point at 180-190°C, and a decomposition temperature of 200°C. The resulted mixture was poured and gently pressed into alumina dies. The samples were then sintered in vacuum, 10-5 Torr for 30 minutes. A linear dependence of thermal conductivity with the measured temperature was observed. The type of heat transmission was primarily conduction at the interparticle necks level. The macro pores created by the polystyrene particles throughout the sample act as thermal insulators. Sound attenuation was found to be a function of frequency and porosity, and also dependent on the powder particles size. The good compression behavior was also evidenced..

Keywords

Metal foams, Bi-porous structures, Hollow particles, Porous materials.

Submitted at: March 10, 2011
Accepted at: July 25, 2011

Citation

E. BRUJ, N. JUMATE, I. VIDA-SIMITI, V. MOLDOVAN, D. NEMEŞ, Study on the physical and mechanical properties of nibased sintered metallic foams, Journal of Optoelectronics and Advanced Materials Vol. 13, Iss. 7, pp. 866-869 (2011)