Hydrogen sensor, hydrogen detection system employing the same, and electrical device with a hydrogen detection system

1. An optical sensor for detecting hydrogen in a fluid in physical contact with the optical sensor, the optical sensor comprising:

an optical fiber, wherein an end portion of the optical fiber is coated with a multilayer including:

a sensing layer, including a film of an alloy, the alloy including Mg, Ni, and M, wherein M is at least one of Zr, Ta, and Hf, and wherein the alloy has the composition Mg x Ni y M z , and wherein x is from 40 to 60, y is from 10 to 40, and z is from 10 to 40; and

a catalyst layer including Pd.

2. The optical sensor of claim 1 , wherein the alloy includes at least one of Mg 52 Ni 20 Zr 28 , Mg 52 Ni 24 Zr 24 , and Mg 55 Ni 27 Ta 18 .

3. The optical sensor of claim 1 , wherein the multilayer includes the sensing layer, the catalyst layer, and a coating layer.

4. The optical sensor of claim 3 , wherein the coating layer includes PMMA and/or PTFE and/or SiO 2 and/or Aluminum Oxide, or has a multilayer structure including at least two of PMMA, PTFE, SiO 2 , and Aluminum Oxide.

5. The optical sensor of claim 1 , wherein the optical fiber is configured such that the optical sensor exhibits a continuous decrease of optical reflectivity in a visible optical range in dependency of a growing hydrogen partial pressure in a fluid in contact with the optical sensor.

6. The optical sensor of claim 5 , wherein the continuous decrease occurs in a temperature region between 5° C. and 150° C. and for a hydrogen partial pressure between 0.5 ppm and 5,000 ppm.

7. The optical sensor of claim 1 , wherein the optical fiber further includes at least one auxiliary layer abutting the sensing layer, the auxiliary layer including Ti.

8. The optical sensor of claim 1 , wherein the multilayer is provided on an end surface of the optical fiber perpendicular to a longitudinal axis of the optical fiber.

9. A detection system for hydrogen in a fluid, comprising:

an optical sensor including:

an optical fiber, wherein an end portion of the optical fiber is coated with a multilayer including:

a sensing layer, including a film of an alloy, the alloy including Mg, Ni, and M, wherein M is at least one of Zr, Ta, and Hf, and wherein the alloy has the composition Mg x Ni y M z , and wherein x is from 40 to 60, y is from 10 to 40, and z is from 10 to 40; and

a catalyst layer including Pd;

a temperature sensor;

a light source;

a light detection device; and

a control unit;

wherein light from the light source is coupled into the optical sensor, and light reflected by the multilayer of the optical sensor is detected by the light detection device; and

wherein the control unit processes an output signal “S 1 ” of the light detection device, determines a hydrogen concentration, and delivers a respective output signal “S 2 ”.

10. The detection system of claim 9 , wherein the control unit is configured to provide an output signal “S 2 ” depending on the hydrogen concentration determined from a reflectivity of the optical sensor and a temperature; and

wherein the output signal “S 2 ” is a continuous function of the hydrogen concentration in the fluid.

11. The detection system of claim 10 , wherein the control unit is configured to deliver a continuous change of the output signal “S 2 ” in a temperature region between 5° C. and 150° C. and for a hydrogen partial pressure in the fluid between 0.5 ppm and 5,000 ppm.

12. The detection system of claim 9 , wherein the control unit is configured to determine the hydrogen concentration by looking up stored data about a reflectivity of the optical sensor at various hydrogen partial pressures and temperatures, and/or to determine the hydrogen concentration from a stored function set, taking into account at least a reflectivity of the optical sensor and a temperature.

13. The detection system of claim 9 , wherein the end portion of the optical fiber is immersed in an oil volume; and

wherein the temperature sensor is provided to measure a temperature of the oil volume at a position adjacent to the multilayer of the optical sensor.

14. A hydrogen sensor, comprising:

an alloy including Mg, Ni, and IA wherein M is at least one of Zr, Ta, and Hf, and wherein the alloy has the composition Mg x Ni y M z , and wherein x is from 40 to 60, y is from 10 to 40, and z is from 10 to 40.

15. The optical sensor as claimed in claim 8 , wherein the multilayer overlaps over an edge of the optical fiber to cover a portion of a circumferential side face of a core of the optical fiber.