RESEARCH INVESTIGATION TO DETERMINE THE OPTIMUM CONDITIONS FOR GROWING SINGLE CRYSTALS OF SELETED BORIDES, SILICIDES AND CARBIDES. Period covered: March 1959 to February 1960
Methods of producing selected crystals in the refractory hard metals class for mechanical and other property determinations were studied. A Verneuil- type process using an arc heat source and argon shield gas was employed. Single crystal boules of titanium diboride and tungsten disilicide, 1/4-inch diameter and up to 4 1/2 inches long, were made, however, most of them cracked upon cooling. The largest single crystal pieces recovered were 1/4-inch diameter and over 1/2-inch long. Dimolybdenum carbide boules had large sections of a "single crystal" Mo/sub 2/C matrix containing about 10% by volume of another phase distributed uniformly through it. No Mo/sub 2/C single crystal pieces free from this phase were made. In very limited work with ditungsten pentaboride only polycrystalline boules were produced. A major problem was encountered in getting powders suitable for Verneuil-type crystal growth. Best results were obtained from compounds prepared by fusing commercially available pure elements and crushing the lumps into a suitable particle size fraction. Process improvements and purer powders are required to produce better quality TiB/sub 2/ and WSi/sub 2/ crystals. More experimental information is required on the molybdenumcarbon and the tungsten-boron systems. (auth)
- Research Organization:
- Linde Co., Newark, N.J.
- NSA Number:
- NSA-14-016982
- OSTI ID:
- 4162991
- Report Number(s):
- WADD-TR-60-52
- Country of Publication:
- United States
- Language:
- English
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