ELEC'I HON >IICROSCOPY 



Application of Gas Reaction Device. 



One oxample of its applicutions of tho old 

 type device is shown (17). Copper mesh is 

 used as a specimen and hydrogen sulfide 

 as reaction gas. Though hydrogen sulfide 

 is a very corrosive gas, the furnace and the 

 surfaces of the pole piece were not remark- 

 ably corroded in the gas atmosphere of 10~^ 

 to 10~' mm Hg at temperatures up to 500°C. 

 At 1 mm Hg, however, the conduction wires 

 of copper and the sylphon bellows which 

 give allowance for the specimen shifting, 

 were covered by corrosion layers after a few 

 hours' operation at about 500°C. 



Fig. 21 shows some stages of the crystal 

 growth of copper sulfide in an atmosphere 

 of 10-2 mm Hg; (a) was taken at 300°C, (b) 

 at 350°C, 5 min after (a) and (c) at 400°C, 

 15 min after (b). In (a), a needle crystal 

 below 0.1 /i in breadth, marked by an arrow, 

 has gro\\^i to a finite length within a part of 

 one second. Then, the axial growth became 

 so slow that it could hardly be observed on 

 the screen, whereas a growth perpendicular 

 to the axial direction began. In (c), the crys- 

 tal, marked by an arrow, has grown to 1 ^t 

 in breadth. 



REFERENCES 



1. BoRRiEs, B. VON, Janzen, S., VDI-Zeitsch- 



rift., 85, 207 (1941). 



2. Ito, K., Ito, T., and Watanabe, M., J. 



Electron Microscopy, Jap., 2, 10 (1954). 



3. Ito, K., Ito, T., Aotsu, T., and Miyamae, 



T., /. Electron Microscopy, Jap., 5, 3 (1957). 



4. Menter, J. W., J. Inst. Met., 81, 163 (1952). 



5. Honjo, G., Kitamura, N., Shimaoka, K., 



AND MiHAMA, K., /. Phys. Soc. Jap., 11, 527 

 (1956). 



6. Watanabe, M., Okazaki, I., Honjo, G., 



AND MiHAMA, K., "Proc. 4th Int. Conf. 

 Elect. Micros.," Berlin (1958). 



7. Watanabe, M., Okazaki, I., and Honjo, G., 



(unpublished). 



8. Sears, G. W., Acta Metal., 1, 457 (1953); 3, 



361 (1955). 



9. Honjo, G. and Watanabe, M., Nature, 181, 



326 (1958). 



10. Meyer, K. H. and Misch, L., Helv. Chern. 



Acta, 20, 232 (1937). 



11. Ito, K., Ito, T., and Watanabe, M., "Proc. 



3rd Int. Conf. Elect. Micros., London," 658 

 (1954). 



12. Okazaki, I., Watanabe, M., and Miiiama, 



K., "Proc. 4th Int. Conf. Elect. Micros.," 

 Berlin (1958). 



13. Hashimoto, H., Tanaka, K., and Yoda, E., 



J. Electron Microscopy , Jap., 6, 8 (1958). 



14. Takahashi, N. and Mihama, K., Acta Met., 5, 



159 (1957). 



15. Ito, T. and Hiziya, K., /. Electron Micros- 



copy, Jap., 6, 4 (1958). 



16. AsHiNUMA, K. AND Watanabe, M., (un- 



published). 



17. Hiziya, K., Hashimoto, H., Watanabe, ^L, 



and Mihama, K., "Proc. 4th Int. Conf. 

 Elect. Micros.," Berlin (1958). 



Masaru Watanabe 

 Kazuo Ito 



SPECIMEN PREPARATION— SPECIAL 

 TECHNIQUES AT LOS ALAMOS 



A IVIodified Aluminum Pressing Replica 

 Technique 



Modifications of an aluminum pressing 

 replica technique for metallic and other suit- 

 able surfaces, first introduced in Germany by 

 Hunger and Seeliger, afford greater yield 

 and wider applicability, which make the 

 method considerably more effective. The 

 necessary pressure within the die is produced 

 by hydrostatic force, transmitted through a 

 medium of hot liquid plastic in place of 

 "cold-pressing" as before. In this way, sen- 

 sitive surfaces can be replicated nondestruc- 

 tively. The method also permits simultane- 

 ous replication of both surfaces of any given 

 specimen and/or similar multiple treatment 

 of several samples in one operation. No addi- 

 tional apparatus is required for application, 

 since the necessary routine equipment, such 

 as metallurgical presses and dies found in 

 most laboratories, may be used without al- 

 terations. 



The modifications as described therefore 

 extend application of this method to surface 

 studies in powder metallurgy, metal-ceram- 

 ics and related industries. 



270 



