The reasons for the decrease in conductivity of graphite electrodes may include the following aspects:
1.Oxidation: Graphite undergoes oxidation when exposed to air for extended periods, forming graphite oxide or other oxides. The formation of these oxides reduces the conductivity of graphite because oxides are typically insulators that hinder the free movement of electrons.
2.Contamination: The surface of the graphite electrode may be covered with impurities or contaminants, which can affect the electron’s conductive path, leading to decreased conductivity. Common contaminants include dust, grease, moisture, etc.
3.Wear: Prolonged use or friction may cause surface wear on the graphite, thereby affecting its conductivity. Wear can result in damage to the graphite layers, reducing the electron’s conduction path and subsequently decreasing conductivity.
4.Crystal defects: Structural defects within the graphite crystal, such as lattice defects, grain boundaries, etc., can also affect its conductivity. These crystal defects scatter electrons, increasing the resistance to electron movement and leading to decreased conductivity.
5.Temperature effects: The conductivity of graphite varies with temperature, typically decreasing at high temperatures. Therefore, if the graphite electrode is exposed to high-temperature environments, conductivity may decrease.
To address the decrease in conductivity of graphite electrodes, measures can be taken to repair or prevent it, such as regular cleaning of the graphite surface to remove contaminants, avoiding prolonged exposure to air, controlling the operating temperature, and using anti-oxidation treatments.