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Produced by the NASA Center for Aerospace Information (CASI)
NASA TECHNICAL MEMORANDUM NASA TM-77421

GAS PRESSURE SINTERING OF P- SIALON WITH Za3

E. Tani, H. Ichinose, K. Kishi

S. Umebayashi and K. Kobayashi

' -A

Translation from "Yokyo Kyokai Shi", Vol. 91, No. 11, 1983

PP. 522-424

(NASA-TM-77421) GAS PRESSURE SINTERING OF

LETA -SIALON WITH Z= 3 (National Aeronautics

and Space Administration) 7 p dC 1102/MF A01

CSCL 11G &3

1•/2 7

N84-23765

Uacla s

19244

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

WASHINGTON, D.C. 20546 April 084
'

STANDARD TITLE PAGE

1. Rep ort No.

NASA TM-77421

2. Goeamsent Accession No. Raclplont'a Cetelag me.

A. Title and 3wbo;tlo S. Regal Dote

84

L P«r.rninR Organisation Code tilts Pressure Sinteriha of -Sialon 0-th

7. Author(&) L Porforasing Organization Rsperi No.

E. Tani, H. Ichinose,. K. Kishi,

S. Umebayashi and K. Kobayashi. 10. Work unit No.

.9. Portono:ng Organization Nome and Address 11. Contract or Grant No.

lio Kanner Associates

.Redwood City, California•94063-

M Type of Report end Period Covaron i

12. ;pontorin; Agency Nome and Addtess Translation

National Aeronautics and Space: Admini

stration, Whashineton D.C. 20546 l id. Sponsoring Agency Code

15. 5u;;!2cen1o1y Notes

Translation from Yodfyo Kyokai Shi, Vol. 91, No. 11 ,1983•,

PP, 522 -524.

I

te. A^shCc'

An experiment was conlucted on beta-sialon in atmospheric

pressure, using a temperature of 2000 0C and 4 MPa nitrogen

atmosphere.

•0R16+NAL PAGE f

OF POOR QUALITY

17. Key Mords (Selected by Author(t)) 1t. Distribution Statement

i

i

I

Unclassified, Unlimited

It. Secvniy C!ovelf. (of this ripo$) 20. Seen$ Clan 1. SS 1 thls Pepe) 21. Me. of Pages 22.

Unclassified Uncfass^f^ed
g

ORIGINAL PAGE 19

OF POOR QUALITY

GAS PRESSURE SINTERING OF (4-SIALON WITH Z=3

E. Tani, H. Ichinose, K. Kishi

S. Umebayashi and K. Kobayashi

Government Industrial Research Institute

Kyushu Sh,!xu-machi, Tosu-shi 841

The Saga. Prefectural Ceramic Researcr Institute

Silicon nitride, an end component of 0 -sialon, decomposes by */52 

(1)

heat of approximately1900°C in 0.1 MPa nitrogen atmosphere. In order

to inhibit the decomposition, it is required to apply approximately

3 MPa nitrogen pressure at the temperature of 2000°C. If (^-sialon

may be fired at the temperature hi gher than 2000°C, it will be possible

to sinter it without producing the low melting temperature phases

such as X phase, and compacts with high resistabili+.y against high

temperatures may be obtained.

(2)

Mitomo has conducted a sintering experiment using P-sialon (S16 -z

Al z 0 z N 8-z : z= 0 - 4.2) in atmosphere pressure, specifically with z=1

at the temperature of 1900 °C and 2 Mpa nitrogen pressure, and he obtained

compacts of the density 2.99 g/cm 3 . There has been no reported sintering

experiments involving temperatures above 2000'C, however. We therefore

conducted an experiment on P-sialon in the atmosphere pressure, applying

the temperature of 2000'C and 4 MPa nitrogen atmosphere. This paper

is a report of our experiment.

[: In our experiment, z=3 was selected for /3-sialon compositions, and

the compositions containin g 0, 2, and 4 equivalent weight % of more

oxygen were set respectively as z=3 (0), 3(+2), and 3(+4).

It

--

*Numbers in the margin indicate pagination in the foreign text.

1 
The raw materials that were used

in the experiment were S1 3N4 (TS-7,

average granule grade 0.6 ^ m) manufactured by Toyo Soda Mfg. Co. Ltd.,

t0

.. - 9

e

. Z_3(o)

Z= 3W)

Z= 3(•4 )

4 `.f .'rte

2

/ T = 2000-C

z 4

PtJ, (MPa )

Fig. 1. lafo-t ul nitrogen i !js pressurc oil

&iisuy and weight change of 6-sialun

%^ 1:h _=3 at '_1(tt)0'C.

0:

0

oa

0 0

4

Q

l G

rn

N ^ ^

0

Y ^

7

to

6

4

0

L

ORIGINAL PAGE 19

OF POOR QUALITY

y NlPa

AIN (average granule gradde, 3.0 Mm)

manufactured by Toshiba Ceramics Co.

Ltd., and Al2 03 ( RA-40, average granule

grade 0.83 Mm) manufactured by Iwatani Kagaku Kokyo Co. Ltd. These raw

materials were measured at the compositions of z=3 (0), 3 (+2), and 3 (+4).

Then, they were mixed with ethanol

as milled by a Si 3N 4 ball for two days,

suction filtered, and vacuum diced.

The mixed materials, approximately

11 g, were pressure formed by 30x30 mm

metal press with the pressure of 98 MPa.

Then, they were treated with the stable water pressure of 490 MPa. Thug,

powders of approximate density 2.0

g/cm 3 were obtained.

The powders wer3 put in a graphite

crucible coated with AN in the order

of z=3(0), 3(+2), 3(+4) from the bottom, around which a granulated composition z=3(+4) powder was filled.

This graphite crucible was set in an

atmospheric pressure furnace (graphite

2

2 MPa

1 rapa

Z. 3( ; 4) , 2000°C

nw . 2. Side views of Y siul"11 with Z=S( 4)

sintrird undo n r,guil gas p ansurr of 1. 2

sn.l 4MI's a :> "C.

!► A., r
011

ORIMAL PA OE E9

OF POOR QJALIIY

heat generator, manufactured by Tooa Shinku Giken KK.) and was fired

at 2000°C in the nitrogen atmospheric pressure of 1, 2, and 4 MPa.

The initial pressure of the nitrogen gas was set so that it would reach

the expected level at 1100 ° C. As for heating, approximately 5 0 minutes

was spent up to 1100 0C, then the temperature was raised at 10 'c/min up

to 2000 9C, where the temperature was maintained for 60 minutes before

cooling.

The fired compacts were weighed, the surface phase was identified

by X-ray defraction, and the density was measured by water substitution

method.

Figure 1 shows the change of compact density and weight. The density

of all z=3 (0), 3(+2) and 3(+4) compacts, was the higherst when the

pressure was 2 MPa, among which z=3( = 2) showed the highest density,

2.96 a/cm3 (96.4%). The weight showed a clear increase from 1 MPa

to 2 Mra, while the increase between 2 MPa and 4 MPa was slightly decreased

The surface of the z=3(0) compact was identified as ^3-sialon and

15R-sialon phases on the top and 15R-sialon on the bottom at 1 MPa,

sialon phase on the top and ^-sialon and 15R-sialon on the bottom at 

2 MPa, ^ -sialon phase on both top and bottom at 4 MPa. As for the compacts of z=3(+2), both the top and bottom contained both ^-sialon and

15R-sialon phases at 1 MPa, while a slight amount of X phase was observed along with 0-sialon at 2 and 4 MPa. As for z=3(=4), measuring

was not conducted on the compact of 1 MPa because it was swolen (Figure

2), and both the top and bottom of 2 and 4 MPa compacts were identified

3
ORIGINAL PAGE IS

OF POOR QUALITY

as ^3- sialon. Additionally, some of the compacts contained the phases

that were not identified.

There was no swelling observed on the com pacts of z=3(0), while

slight swelling was observed on the bottom of the compacts of z-3(+2)

at 1 and 2 MPa. As for z= 3 (+4), the swelling was well developped on

both the top and bottom at 1 MPa, slight swelling was observed on the

bottom at 2 MPa, and no swelling at 4 MPa. (Figure 2) This swelling

is considered to have developped by the gas generated by the thermal

decomposition. Because this thermal decomposition was inhibited by the

increase of the nitrogen gas pressure, it indicates that the atmospheric

pressure sintering method is effective for sialon sintering.

We p lan to report the details of the result of this sialon

atmospheric pressure sintering in the coming future. 

4 
REFERENCE

1. Greskovich, C. et al., Commun. Am. Ceram. Soc., 64, 96-7, 1981.

2. Mitomo, M., Proceedings of International Symposium cf Factors in

Densification and Sintering of Oxide and Non-oxide Ceramics,

Hakone, 1978, P. 539.

Lot