Method of forming a relatively stable slip of silicon metal particles and yttrium containing particles
The method concerns forming a relatively stable slip of silicon metal particles and yttrium containing particles. In one embodiment, a casting slip of silicon metal particles is formed in water. Particles of a yttrium containing sintering aid are added to the casting slip. The yttrium containing sintering aid is a compound which has at least some solubility in water to form Y/sup +3/ ions which have a high potential for totally flocculating the silicon metal particles into a semiporous solid. A small amount of a fluoride salt is added to the casting slip which contains the yttrium containing sintering aid. The fluoride salt is one which will produce fluoride anions when dissolved in water. The small amount of the fluoride anions produced are effective to suppress the flocculation of the silicon metal particles by the Y/sup +3/ ions so that all particles remain in suspension in the casting slip and the casting slip has both an increased shelf life and can be used to cast articles having a relatively thick crosssection. The pH of the casting slip is maintained in a range from 7.5 to 9. Preferably, the fluoride salt used is one which is based on a monovalent cation such as sodium or ammonia. The steps of adding the yttrium containing sintering aid and the fluoride salt may be interchanged if desired, and the salt may be added to a solution containing the sintering aid prior to addition of the silicon metal particles.
- Assignee:
- Ford Motor Co.
- Patent Number(s):
- US 4471060
- Application Number:
- TRN: 85-000175
- OSTI ID:
- 6141731
- Resource Relation:
- Patent File Date: Filed date 8 Jul 1983; Other Information: PAT-APPL-512095
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SILICON ALLOYS
SLIP CASTING
YTTRIUM ALLOYS
ADDITIVES
AMMONIUM FLUORIDES
CASTING
DISSOLUTION
FLOCCULATION
PARTICLES
SODIUM FLUORIDES
SOLUBILITY
STABILITY
WATER
ALKALI METAL COMPOUNDS
ALLOYS
AMMONIUM COMPOUNDS
FABRICATION
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
OXYGEN COMPOUNDS
PRECIPITATION
SEPARATION PROCESSES
SODIUM COMPOUNDS
360101* - Metals & Alloys- Preparation & Fabrication