Resistive material, resistor, and manufacturing method of resistive material

Patent metadata

Field	Value
Publication number	US-11495374-B2
Application number	US-201917263988-A
Country	US
Kind code	B2
Filing date	Aug 2, 2019
Priority date	Aug 29, 2018
Publication date	Nov 8, 2022
Grant date	Nov 8, 2022

Abstract

A resistive material for sensing current contains particles having an electrically insulating property and a metal body having a three-dimensional network enclosing the particles, and a ratio of the metal body to the whole of the resistive material is 30 vol % or more and 80 vol % or less.

First claim

The invention claimed is:

1. A resistive material for sensing current, the resistive material comprising:
particles having an electrically insulating property and a metal body having a three-dimensional network enclosing the particles, so as to define a matrix material, wherein
the metal body is formed of at least one selected from a group consisting of nichrome, copper-manganese, and copper-nickel,
the resistive material is a sintered body obtained by sintering a metal powder and the particles,
an aspect ratio of the particle of the metal powder is 1.0 or more and 2.0 or less, the aspect ratio defined by ((d-t)/d) wherein d is a length of a long side of the particle and t is a length of a short side of the particle, and
a ratio of the metal body contained in the resistive material is 30 vol % or more and 80 vol % or less, and
wherein the three-dimensional network is formed by the metal body that has been melted around the resistive materials.

2. The resistive material according to claim 1 , wherein the particles are formed of at least one selected from a group consisting of alumina, aluminum nitride, silicon nitride, and zirconia.

3. The resistive material according to claim 1 , wherein a temperature coefficient of resistance is equal to or lower than 100 ppm.

4. The resistive material according to claim 1 , wherein a specific resistance is 200 μΩ·cm or more and 30000 μΩ·cm or less.

5. A resistor for sensing current, the resistor comprising:
a resistive material containing a metal body having an electrically conductive property and particles having an electrically insulating property, the metal body having a three-dimensional network enclosing the particles, wherein the three-dimensional network is formed by the metal body that has been melted around the particles so as to define a matrix, and wherein the metal body is formed of at least one selected from a group consisting of nichrome, copper-manganese, and copper-nickel, the resistive material is a sintered body obtained by sintering a metal powder and the particles, and an aspect ratio of the particle of the metal powder is 1.0 or more and 2.0 or less, the aspect ratio defined by ((d-t)/d) wherein d is a length of a long side of the particle and t is a length of a short side of the particle, and wherein a ratio of the metal body contained in the resistive material is 30 vol % or more and 80 vol % or less, and
two electrodes, the resistive material being sandwiched between the two electrodes, wherein
the metal body is formed so as to be continuous in the resistive material in a direction between the electrodes.

6. A manufacturing method of a resistive material comprising:
a step of mixing particles having an electrically insulating property and a metal powder having an electrically conductive property, wherein the metal powder forms a matrix;

the metal body is formed of at least one selected from a group consisting of nichrome, copper-manganese, and copper-nickel, the resistive material is a sintered body obtained by sintering a metal powder and the particles, an aspect ratio of the particle of the metal powder is 1.0 or more and 2.0 or less, the aspect ratio defined by ((d-t)/d) wherein d is a length of a long side of the particle and t is a length of a short side of the particle, and wherein a ratio of the metal body contained in the resistive material is 30 vol % or more and 80 vol % or less; and
a step of sintering a mixed powder obtained by the mixing step at a predetermined temperature lower than a melting point of the metal powder, the sintering being performed under pressure.

Assignees

• Koa Corp

Inventors

• Matsubara Shuhei
• Nakamura Keishi

Classifications

• H01C7/13

  current-responsive · CPC title

• H01C17/00

  Apparatus or processes specially adapted for manufacturing resistors (providing fillings for housings or enclosures H01C1/02; reducing insulation surrounding a resistor to powder H01C1/03; manufacture of thermally variable resistors H01C7/02, H01C7/04) · CPC title

• H01C7/008 Primary

  Thermistors (H01C7/02 - H01C7/06 take precedence) · CPC title

• G01R19/0092

  Measuring current only · CPC title

• G01R15/146

  Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop (if no voltage isolation is involved G01R1/203 or G01R19/0092) · CPC title