Comparison of oxidation resistance between manganese copper alloy resistors and constantan alloy resistors

There is a significant difference in oxidation resistance between manganese copper alloy resistors and constantan alloy resistors. The following is a detailed comparison of their oxidation resistance:
Oxidation resistance of manganese copper alloy resistors

Formation of oxide film: When manganese copper alloy is exposed to air at high temperatures, a layer of oxide film will form on the surface. This oxide film is mainly composed of copper oxide (CuO) and manganese oxide (MnO ₂), which can slow down the oxidation process to a certain extent.
Oxidation resistance: The oxidation resistance of manganese copper alloy is greatly affected by temperature. When the temperature is below 250 ° C, the oxide film on the surface of the alloy is denser, which can effectively prevent further oxidation. However, when the temperature rises above 400 ° C, the structure of the oxide film becomes loose, and oxygen is more likely to pass through the oxide film and react with the substrate, resulting in a significant increase in oxidation rate.
Influencing factors: The oxidation resistance of manganese copper alloy is also affected by factors such as alloy composition and heat treatment process. For example, excessive manganese content may lead to an accelerated oxidation rate; Reasonable heat treatment processes can improve the oxidation resistance of alloys.

The oxidation resistance of copper alloy resistors

Characteristics of oxide film: Chromium element in constantan alloy plays a key role in the oxidation process. Chromium reacts with oxygen in the air to form a dense Cr2O3 oxide film. This oxide film is very stable and can effectively prevent further invasion of oxygen, thereby significantly improving the oxidation resistance of the alloy.
High temperature stability: Copper alloy can still maintain good oxidation resistance at high temperatures. Even at temperatures as high as 800 ° C, the oxidation rate of constantan alloy is relatively low, demonstrating excellent high-temperature oxidation resistance.
Application advantages: Due to its excellent oxidation resistance, constantan alloy is particularly suitable for harsh environments with high temperature, high humidity, and strong corrosiveness. In these environments, constantan alloy resistors can work stably for a long time and are not easily prone to failure due to oxidation.

summary
Manganese copper alloy resistors and constantan alloy resistors each have their own characteristics in terms of oxidation resistance. Manganese copper alloy resistors exhibit good oxidation resistance at low temperatures, but the oxidation rate accelerates at high temperatures; Copper alloy resistors, on the other hand, have excellent high-temperature oxidation resistance due to their dense Cr2O3 oxide film. Therefore, when selecting resistors, comprehensive consideration should be given to specific operating temperatures, environmental conditions, and antioxidant requirements. If resistors need to be used in high temperatures or harsh environments, constantan alloy resistors may be a better choice.