# Graphene-Enhanced CuW Composites for High-Voltage Circuit Breaker Electrical Contacts
## 3 Results and Discussion
### Ablation Resistance of Graphene-Enhanced CuW Electrical Contacts  
The innovative graphene-enhanced CuW electrical contacts have been integrated into the 252 kV/63 kA high-voltage SF\({}_{6}\) circuit breaker, demonstrating an impressive 20 times effective full-capacity of continuous breaking in electrical durability tests, compared to the ordinary CuW electrical contacts which only achieved 16 times. As evident from Figure 8 and Table 2, the ablation degree of the graphene-enhanced CuW80 electrical contacts remains significantly lower even after 20 consecutive full-capacity 63 kA short-circuit current breakings, compared to the ordinary CuW80 contacts after just 16 breakings. Furthermore, the dimensional changes observed in both the stationary and movable contacts following full-capacity breaking are notably smaller in the graphene-enhanced CuW80 electrical contacts compared to their non-graphene counterparts. The mechanisms underlying the significant improvement in the ablation resistance of CuW electrical contacts by the integration of graphene are intricate and multifaceted. The unique properties of graphene play a pivotal role in enhancing the durability and performance of electrical contacts. Firstly, the pinning effect induced by graphene during ablation is a crucial mechanism. This pinning effect hinders the flow of copper within the contact material, effectively mitigating the volatilization and enrichment of copper in the molten pool that occurs during the ablation process. By limiting the copper loss, the mass loss of the electrical contacts is significantly reduced, thereby enhancing their durability. Secondly, the exceptional electrical and thermal conductivity of graphene play a vital role. Graphene's ability to quickly guide the heat generated by the arc ensures that the heat is efficiently dissipated, contributing to a shorter arc duration time. This reduction in arc duration not only minimizes the thermal stress on the contacts, but also significantly reduces the mass ablation that occurs during the arc event. Furthermore, the low work function of graphene promotes arc breakdown preferentially on the graphene phase. This preferential breakdown not only disperses the breakdown energy, but also promotes the dispersion of the arc, ensuring that the arc energy is distributed more uniformly across the contact surface. This dispersion of the arc energy reduces the concentration of heat at specific points, minimizing the loss of copper in the ablation center and further enhancing the durability of the electrical contacts. In summary, the combination of the pinning effect, exceptional electrical and thermal conductivity, and preferential arc breakdown on the graphene phase collectively leads to substantial enhancements in the ablation resistance of CuW electrical contacts. These advancements not only bolster the durability of the electrical contacts, but also facilitate more efficient and dependable operation of the high-voltage circuit breakers in which they are employed. Based on previous literature comparisons, it is evident that the properties of CuW composites vary with changes in their compositional content. Higher copper content offers superior electrical and thermal conductivity, whereas increased tungsten content enhancesmechanical properties and ablation resistance. However, these two aspects cannot be fully optimized simultaneously, as an increase in one often leads to a decrease in the other [18]. By the third component doping modification, the enhancement of certain properties in composite materials is achievable, but it often results in a decrease in electrical conductivity, making it difficult to achieve a balance between the two [18; 19; 20; 21; 22]. Graphene, with its exceptional properties, can effectively enhance the overall performance of CuW composites when used as an additive. However, previous research on graphene-modified CuW composites has primarily focused on simulations, material microstructure characterization, and electrical ablation performance evaluation of samples.