Ford Motor Company Limited

Massachusetts Institute of Technology

Krishnamoorthy Subramanian

Andre Ezis

Shyam K Samanta

Nathan H Cook

David Moskowitz

Orrin A Newton

A method is disclosed comprising placing in a hot pressing environment a controlled mixture of a first powder of Si.sub.3 N.sub.4 containing a controlled amount of SiO.sub.2 (with or without a limited amount of milling media) with a second powder consisting essentially of Y.sub.2 O.sub.3, hot pressing the controlled mixture, and cooling the resultant unitary object. A novel silicon nitride comprising a unitary object is disclosed which can be shaped to form a novel cutting tool useful for machining metal such as cast iron. The object has selected crystalline phases formed beta Si.sub.3 N.sub.4 and beta prime Si.sub.3 N.sub.4 and has intergranular crystalline secondary phases consisting essentially of YSiO.sub.2 N, Y.sub.10 Si.sub.17 N.sub.4 O.sub.23 and Y.sub.2 Si.sub.2 O.sub.7 with the YSiO.sub.2 N phase representing at least a 25% volume fraction of the secondary phases and comprising essentially all of the yittria-silicon oxide.

Ceramic cutting tool formed from Si.sub.3 N.sub.4 --Y.sub.2 O.sub.3

A method is disclosed comprising placing in a hot pressing environment a controlled mixture of a first powder of Si.sub.3 N.sub.4 containing a controlled amount of SiO.sub.2 (with or without a limited amount of milling media) with a second powder consisting essentially of Y.sub.2 O.sub.3, hot pressing the controlled mixture, and cooling the resultant unitary object. A novel silicon nitride comprising a unitary object is disclosed which can be shaped to form a novel cutting tool useful for machining metal such as cast iron. The object has selected crystalline phases formed beta Si.sub.3 N.sub.4 and beta prime Si.sub.3 N.sub.4 and as intergranular crystalline secondary phases consisting essentially of YSiO.sub.2 N, y.sub.10 Si.sub.17 N.sub.4 O.sub.23 and Y.sub.2 Si.sub.2 O.sub.7 with the YSiO.sub.2 N phase representing at least a 25% volume fraction of the secondary phases and comprising essentially all of the yittria-silicon oxide.

Ceramic cutting tool formed from Si.sub.3 N.sub.4 -Y.sub.2 O.sub.3 -SiO.sub

A method of machining cast iron by using a ceramic cutting tool of specific composition at specified removal rates which results in increased tool life.

Method of cutting cast iron with Si.sub.3 N.sub.4 composite cutting tool

A process for machine cutting of cast iron with a shaped tool which is a ceramic having as constituent ingredients about 4 to about 12% by weight Y.sub.2 O.sub.3 and a balance consisting essentially of Si.sub.3 N.sub.4 and which has a density of at least 3.25 gm./cm.sup.3.

ethod of using Si.sub.3 N.sub.4.Y.sub.2 O.sub.3.SiO.sub.2 ceramic system

A process for implanting a precise quantity of radioactive metal on a metal substrate such as a cutting tool or other metal part subject to wear at the area or areas where the part is expected to wear during its operation. The presence of the radioactive spot can be sensed to determine the extent of wear during use. The radioactive metal is deposited from a wire formed of a core of the radioactive metal surrounded by a sheath of metal having a high thermal and electrical conductivity relative to the core. In operation, the wire contacts the metal surface under pressure and electric current is passed through the wire in order to (1) form a pit on the tool surface, (2) weld the radioactive metal in the pit and (3) evaporate a small portion of the conductive sheath adjacent the pit. A second current then is passed through the wire to break it near the bottom of the pit, leaving a small quantity of radioactive material welded to the bottom of the pit.

Article for implanting radioactive metal on a substrate

A cutting tool holding system is disclosed. The system employs an improved chip breaker element having a lip mechanically gripping a radially extending and exposed edge of the cutting tool insert; the breaker element is held against relative sliding movement by a pin connection to a clamp which laterally urges the element and tool against the shank. Thus, the cutting insert is locked in place within the tool shank pocket avoiding premature failure from undue stress during prolonged tool cutting. The breaker element also has a chip breaker surface comprised of an arcuate segment spaced uniformly from the insert cutting point and a straight segment extending from the arcuate segment along the exposed edge of the insert.

Modified tool holder to prevent insert slippage and fracture

A process for continuous or interrupted machine cutting of solid cast iron by milling, turning or boring with a shaped tool, wherein said shaped tool is a ceramic consisting essentially of Si.sub.3 N.sub.4 and 4-12% by weight Y.sub.2 O.sub.3, produced by hot pressing at a pressure and a temperature of 1700.degree.-1750.degree. C. to achieve substantially full density.

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Inkster, MI, United States of America

Krishnamoorthy Subramanian