Ormet Corporation

Sam Fu

Xiaomei Xi

Pradeep R Gandhi

Lutz W Brandt

Goran Matijavesic

Catharine Gallagher

In accordance with the present invention, there are provided novel metal-containing compositions useful for the preparation of electrical resistance devices (e.g., resistors and thermistor elements). Compositions according to the invention comprise at least one low melting point metal material, and optionally a higher melting point metal material, with the further presence of a binder system also being optional. Compositions according to the invention exhibit a wide range of resistivity and a wide range of values for temperature coefficient of resistance (TCR). Compositions with low values for TCR are useful for resistor applications while compositions with large values for TCR are useful for thermistor applications. Resistor or thermistor elements can be produced by applying compositions according to the invention onto suitable substrates and subsequently alloying (i.e., curing and/or sintering) the compositions. During curing/sintering, the metal or metal alloy powders undergo transient liquid phase sintering to form a continuous metallurgical network. The electrical conduction of the resulting resistor and/or thermistor elements is achieved as a result of the continuous metallurgical network. Resistance and values for TCR of resistors and/or thermistors prepared employing compositions according to the invention are dependent on the intermetallic compounds formed as a result of the alloying/sintering process. Resistors and thermistor elements formed employing compositions according to the invention are stable up to approximately 250.degree. C. and can be used in the temperature range of about -50.degree. C. up to about 200.degree. C. These metal-containing compositions are compatible with polymer, metal and other types of substrates, are highly reliable as compared to existing technology.

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Del Mar, CA, United States of America

Sam Fu