Lecture Notes VOxygen sensors based on

oxygen ion conductors

Dependence of domain boundaries on oxygen pressure and temperature

Pp

Pp

Pn

Pn

Ionic domains

p-cond.

n-cond

Function

/4F

Porous Pt electrodes – reactions takes place in triple points

1

Calibration curve

Short circuit due toelectronic conduction

High temperature oxygen sensors

• Temperature range: 600 - 1500ºC• Pressure range becomes smaller with

increasing temperature.• Good resistance toward corrosive

atmospheres.• Good temperature shock resistance.• It is the equilibrium oxygen pressure which

is measured!

In-situ measurements

Examples:

- Combustion control in gas- and coal fired furnaces;

-Atmosphere control in sintering and heat treatment furnaces.

- Combustion of waste;

In-situ oxygen control in molten steel.

Electrolyte, Belgium

- sensor

Catalytic emission-control

Engine

Exhaust

Control unit

Cross section of λ-sensor

Extractive control of welding gases

TIG- tungsteninert gas welding

Argon

Gas on backside must be controlled.

Welding of stainless steel.

Extractive control of welding gases

TIG- tungsteninert gas welding

Argon

PBI-Dansensor

Atmosphere control

Fluid N2

850 m3/h

Nitrogen freeze dryer

Extractive quality control

Packed meat and vegetables.

PBI-Dansensor

Repetition

How function an oxygen sensor?

Typical applications of oxygen sensors.