Dispersion-hardened platinum materials match rhodium alloys

International News

Vickers hardness HV 3

Dispersion-hardened platinum materials match rhodium alloys

Strength (Rm/

20 C N/mm 2 N/mm 2

100h/1400 C N/mm 2

1000h/1400 C N/mm 2

Pt

390

130

06

-

R10Rh

750

280

44

2

R5Au

930

330

1

-

FKS 16 Pt

675

225

16

10

FKS 40 Pt

1100

375

20

15

FKS 16 PtRh

1500

440

22

15

FKS 16 PtAu

1200

350

5

2

Comparison of some important data for conventional and fine-grain stabilised platinum materials.

Dispersion hardening is used in platinum alloys to prevent the reduction of hardness with increasing temperature. Forming hardness is thus retained at temperatures approaching melting point. As a result, articles can be manufactured at a reduced level of platinum consumption and can be used without supporting elements. Dimensional stability is improved and the risk of sudden cracking is eliminated. The mechanical properties of dispersion-hardened platinum materials depend not only on the thermodynamic stability of the dispersoids, but also of the amount which is used. By optimising the dispersoid content, Degussa claims to have improved unalloyed platinum to such an extent that the high temperature stability is almost on a par with rhodium-alloyed material. This is of great benefit where the alloying constituent rhodium poses problems. Degussa: Postfach 11 05 33, D-6000 Frankfurt 11, FRG. Tel: +49 218-2860.

Compar~on of crucible made from the dispersion hardened material FKS 16 PtAu and one with thicker walls made from the conventional alloy Pt5Au, after use in identical conditions

360

MATERIALS & DESIGN Vol. 9 No. 6 NOVEMBER/DECEMBER 1988