Can the aluminum oxide titanium coating be measured with an eddy current coating thickness gauge? The eddy current coating thickness gauge uses the characteristics of conductivity to the substrate. After measuring the coating on it, whether it can be measured with the eddy current coating thickness gauge, it is necessary to clearly understand whether the alumina titanium coating is conductive or not.

Guoou GTS820NF split eddy current coating thickness gauge

We know that pure alumina and pure chromium oxide coatings have weak dielectric properties, high resistance, and certain insulation capabilities (under high temperature and high voltage, there is still the possibility of electrical breakdown and loss of insulation). Titanium oxide coating has semiconductor properties and can conduct electricity. So does the alumina-titanium ceramic coating containing titania also have the ability to conduct electricity or does the alumina-titanium coating also provide insulation?

After joint experiments with customers, it is concluded that when the titanium oxide content is less than 20%, the alumina titanium ceramic coating is still insulative. When the titanium oxide content exceeds 20%, the alumina titanium ceramic coating has the ability to conduct electricity.

Chemical knowledge tells us that due to the reduction effect of TiO2 in the high-temperature jet of plasma spraying, the conductivity of the coating is attributed to the loss of oxygen by TiO2. In the plasma spraying process, TiO2 is reduced to form an oxygen-deficient phase, which is the reason why TiO2 has semiconductor characteristics. Due to the formation of an oxygen-deficient phase, oxygen vacancies are generated in TiO2 and structural defects are formed. Most of these defects are formed in the high-temperature melting stage, and with rapid cooling, they are retained in the coating. When energized and heated, these defects play a major role in electrical conduction. As the temperature rises, some oxygen ions escape from the TiO2 to the gas phase, forming oxygen vacancies. As the oxygen defects increase, more and more oxygen vacancies are generated, and the electron concentration in the conduction band increases, thereby reducing the alumina titanium ceramics The resistivity of the coating.

Guoou GTS8102 Integrated Eddy Current Coating Thickness Gauge

Therefore, the resistivity of the alumina titanium ceramic coating increases with the increase of the Al2O3 content, which means that the higher the TiO2 content, the stronger the conductivity of the ceramic coating. On the other hand, the resistivity of the alumina-titanium ceramic ceramic coating decreases exponentially with the increase of temperature.

Summarize:

If we use the eddy current coating thickness gauge to measure the alumina titanium ceramic coating, the measurement result will generally appear, but this value may not be accurate, so it is not very referenceable, so it is not recommended to measure it. If you have this aspect For measurement needs, please contact us.