Claims
- 1. A method for forming an article from iron powder comprising
- compacting a powder mixture comprising plain iron particles and a hypereutectic copper phosphorus sintering agent, and
- sintering the compact at a temperature between about 950.degree. C. and 1120.degree. C. to cause the copper phosphorus agent to form a liquid capable of wetting the surface of the iron particles, said sintering being carried out for a time sufficient for phosphorus to diffuse into the iron particles and for the remaining copper-enriched liquid to flow and wet iron surfaces in the compact and thereafter form a solidified copper-rich layer on pore surfaces within the product sintered article.
- 2. A method for forming an article from iron powder metal comprising
- compacting a powder mixture comprising a major portion of iron particles and up to about 7 weight percent of hypereutectic copper-phosphorus particles containing at least 12 weight percent phosphorus, and
- sintering the compact at a temperature between about 950.degree. C. and about 1120.degree. C. for a sufficient time to cause phosphorus to diffuse uniformly throughout the iron particles and to form a copper-enriched liquid that coats pore surfaces in the compact and, upon solidification, forms a copper-rich film on pore surfaces within the sintered article, whereby said sintering produces an improved combination of ductility and strength in the product article.
- 3. A method for forming an article from powder metal comprising
- compacting a powder mixture comprising a major portion of low-carbon iron particles and between about 2 to about 5 weight percent of hypereutectic tricopper phosphide Cu.sub.3 P compound powder, and
- sintering the compact at a temperature between about 970.degree. C. to 1100.degree. C. for a sufficient time to cause the Cu.sub.3 P powder to form a liquid that wets the iron powder surfaces, a major portion of the phosphorus diffusing during said sintering into the iron particles, the remaining copper-enriched liquid forming a coating on pore surfaces in the product article, whereby the sintered article displays an improved combination of ductility and strength.
- 4. A method for forming an article from powder metal comprising
- sintering a compact formed of a powder mixture comprising a major portion of plain iron particles and a hypereutectic copper phosphorus sintering agent, said sintering being carried out at a temperature and for a time suitable for diffusing phosphorus substantially uniformly throughout the iron and for forming a transient copper-base liquid phase that wets iron surfaces in the compact, said sintering continuing for a time sufficient to deplete phosphorus from the liquid phase to a concentration whereat said phase solidifies, thereby forming a copper-rich film that coats pore surfaces in the article.
- 5. A method for forming an article from powder metal comprising
- compacting a powder mixture comprising a major portion of plain iron particles and up to about 7 weight percent of tricopper phosphide compound powder, and
- sintering the compact at a suitable temperature above about 950.degree. C. to diffuse phosphorus from the phosphide powder into the iron and to form a transient copper-rich liquid that wets iron surfaces in the compact, said sintering continuing for a time sufficient to diffuse phosphorus substantially uniformly throughout the iron and to deplete phosphorus from the liquid to a suitably low concentration whereat the liquid solidifies at the sintering temperature to form a copper-rich coating on pore surfaces in the product sintered article.
Parent Case Info
This is a continuation of application Ser. No. 139,102, filed Apr. 10, 1980, now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
2213523 |
Jones et al. |
Sep 1940 |
|
2226520 |
Lenel |
Dec 1940 |
|
3674472 |
Kimura et al. |
Jul 1972 |
|
Non-Patent Literature Citations (2)
Entry |
Jones, Fundamental Principles of Powder Metallurgy 1960, pp. 504, 505, 508, 509. |
Bockstiegel et al., "Influence of Various Alloying Additions on Case Hardening of Sintered Steel Parts", by Hoganas Presented 9-66 in Czechoslovakia. |
Continuations (1)
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Number |
Date |
Country |
Parent |
139102 |
Apr 1980 |
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