# US 5,708,408 A · Electric resistance element

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- Number: US 5,708,408 A
- Document ID: US5708408A
- Status: Granted
- Kind: A
- Application number: 08/627,040
- Filed: 1996-04-03
- Granted: 1998-01-13
- Earliest claimed: 1995-04-11
- Assignees: Kanthal AB
- Inventors: Mats Sundberg
- Web page: https://patentgrep.com/patent/US5708408A

## CPC

- H01C 7/00: Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material (consisting of loose powdered or granular material H01C8/00; resistors having potential barriers, e.g. field-effect resistors, H10D1/40 - H10D1/43, H10K10/10; semiconductor devices sensitive to electromagnetic or corpuscular radiation, e.g. photoresistors, H10F30/00; magnetic field controlled resistors H10N50/10; bulk negative resistance effect devices H10N80/00)
- C04B 35/58092: {based on refractory metal silicides}
- C04B 2235/3813: Refractory metal borides
- C04B 2235/6021: Extrusion moulding
- C04B 2235/6583: Oxygen containing atmosphere, e.g. with changing oxygen pressures
- C04B 2235/80: Phases present in the sintered or melt-cast ceramic products other than the main phase
- C04B 2235/85: Intergranular or grain boundary phases
- C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- C04B 2235/9684: Oxidation resistance
- H01C: RESISTORS
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE

## Abstract

An electrical resistance element of the molybdenum silicide type including at least one hot zone and at least two lead-in conductors. The hot zone includes an homogenous silicide material that contains molybdenum and tungsten having the chemical formula Mo.sub.x W.sub.1-x Si.sub.2, where x is between 0.5 and 0.75. From 10% to 40% of the total of the silicide material is replaced with at least one of the compounds molybdenum boride or tungsten boride; those compounds are present in the silicide material in particle form.

## Claims

### Claim 1

An electric resistance element of the molybdenum silicide type comprising at least one hot zone and at least two lead-in conductors, wherein the hot zone includes an homogenous silicide material that contains molybdenum and tungsten having the chemical formula Mo.sub.X W.sub.1-X Si.sub.2, where x is between 0.5 and 0.75, wherein from 10% to 40% of the total weight of the silicide material is replaced with at least one of the compounds molybdenum boride or tungsten boride that are present in the silicide material in particle form.

### Claim 2 (depends on 1)

An electric resistance element according to claim 1, wherein x is between 0.6 and 0.7.

### Claim 3 (depends on 1)

An electric resistance element according to claim 1, wherein said compounds constitute between 10% and 20% of the total weight.

### Claim 4 (depends on 1)

An electric resistance element according to claim 1, wherein at least a major part of said compounds is molybdenum boride.

### Claim 5 (depends on 1)

An electric resistance element according to claim 1, wherein the molybdenum boride is selected from the group consisting of MoB, Mo.sub.2 B, MoB.sub.2 and Mo.sub.2 B.sub.5 and mixtures thereof.

### Claim 6 (depends on 1)

An electric resistance element according to claim 1, wherein the tungsten boride is selected from the group consisting of WB, W.sub.2 B, WB.sub.2 or W.sub.2 B.sub.5 and mixtures thereof.

### Claim 7 (depends on 1)

An electric resistance element according to claim 1, wherein the molybdenum boride is MoB and the tungsten boride is WB.

### Claim 8 (depends on 1)

An electric resistance element according to claim 1, wherein said lead-in conductors include a material which corresponds to one of the materials from which the resistance element is formed.

### Claim 9 (depends on 1)

An electric resistance element according to claim 1, wherein x is about 0.66.

### Claim 10 (depends on 1)

An electric resistance element according to claim 1 wherein said compounds constitute about 15% of the total weight.