SCIENTIFIC ABSTRACT AVGUSTINIK, A. I. - AVGUSTOVSKIY, I. Y.

• Document Type: CREST
• Collection: Scientific Abstracts
• Document Number (FOIA) /ESDN (CREST): CIA-RDP86-00513R000102610018-2
• Release Decision: RIF
• Original Classification: S
• Document Page Count: 100
• Document Creation Date: November 2, 2016
• Document Release Date: June 6, 2000
• Sequence Number: 18
• Publication Date: December 31, 1967
• Content Type: SCIENCEAB

I
:ACCESSION NR: AP4005835 S/0226/63/000/006/001110017
AUTHOR: Avgustinlk, A. I.; Vicldergauz, V. Sh.; Gropyanov. V.
M.; D~ozdetskaya.
G. V.
!TITLE: Effect of powder fineness on the density of nioblum
carbide parts at
-various sintering temperatures
SOURCE: Poroshkovaya metallurglya, no. 6. 1963, 11-17
;1OPIC 1AGS: niablum carbide, sintered nioblum carbide, nloblum
carbide powder,
nlobium carbide sintering, niob;um carbide density, sIntering,
powder metallurgy,
density
ABSTRACT: Nlobium carbide sVnteirs poorly due to Its high
malting point (37SO K),
leading to lower microhardnesis. The present authors thernfore
studied the relation"
ship between particle size, sintering temperaLure, density and
heat resistance of
NbC and attempted to find methods for producing nioblum carbide
powder with a rela-
'tive density not lower than 90% of the theoretical value at
low sintering tempera-
,tures. This Is very Important for creating heat resistant
structures. Pulveriza-
,tIon In vibro-lbilis was used to obtain fine particles of
nlobium carbide, thus In-
Icreasing the surface enjr9y prior to cold pressing. Fig. I In
the Enclosure shows
,_t~j._effect of the sintering tetnp(trature on the specific
gravlty of nloblum carbide
Card 1/4

ACCESSION NR: AP4005835-
with varying Initial specific surface area. This test was performed
on the
Dcryagin device. As seen from the graph in Fig. 2 of the Enclosure,
greater disper-
sion of the powder leads to higher density at lower temperatures. Two
formulas are
proposed by the authors for relating the sintering temperature and
fineness of the
carbide powder. Experimental data and the theoretical values obtained
from these
formulas differed by not over 1-1.5%. Tests performed by the autihors
also corrobo-
rated the phenomenologic theory mentioned in articles by P1. S.
Kovallchenko, G. 11.
Samsonov and V. V. Skorokhod. It was found that a relative density of
niobium clir-
bide powder of 6p to 97% can only be obtained with very fine powder
ond sinterincl
temperatures.,