Abstract
AgSnO2 electrical contact material with greenery and good performance has the most potential to replace the toxic AgCdO. However, SnO2 in AgSnO2 contact material is a kind of semiconductor with wide band gap, which is almost insulated and has high hardness, resulting in the increase of contact resistance and temperature rise, and easy to form microcracks. First principle based on density functional theory are used to simulate three doping ratios (8.3%, 12.5%, 16.7%) of rare earth element Gd doped SnO2. The simulation results show that when the doping ratio is 12.5%, electrical performance is the best. As the doping ratio increases, the smaller the hardness, the higher the probability of microcracks. To more objectively obtain the doping ratio with the best comprehensive performance, the comprehensive evaluation model of Technique for Order Preference by Similarity to Ideal Solution with entropy weight is adopted to evaluate, and the performance with doping ratio of 12.5% is the best. Finally, it is verified by experiments. Different ratio of Gd doped SnO2 powders are prepared by the sol-gel method, and the X-ray diffraction test proves that the sol-gel method can realize the substitution doped model established by simulation. The doped AgSnO2 is prepared by powder metallurgy method, and its electrical performance and hardness are measured. The theory and experiment can be well matched, which proves the feasibility and credibility of simulation. It provides a new idea and scientific reference for the research on doping to improve the properties of AgSnO2 contact material.
Highlights
AgCdO contact material has the advantages of resistance to arc erosion and fusion welding, low contact resistance, stability, and the applied current ranges from tens to thousands, which was once called ‘‘universal contact’’ [1], [2]
When we study the doping ratio with the best comprehensive performance, sometimes all performance parameters obtained under a certain doping ratio are not the best at the same time
EVALUATION The comprehensive evaluation can calculate synthesized indicators according to the multi indicators, simplify the multidimensional space problems into one-dimensional space problem, and rank the evaluation objects according to the values of the comprehensive indicators
Summary
AgCdO contact material has the advantages of resistance to arc erosion and fusion welding, low contact resistance, stability, and the applied current ranges from tens to thousands, which was once called ‘‘universal contact’’ [1], [2]. Y. Zhang et al.: Research on Simulation, Experiment and Evaluation Method of Different Ratio Gd Doped AgSnO2 Contact Material high decomposition temperature and non-conductivity is easy to accumulate on the contact surface, which increases the contact resistance and affects the electrical life. From the density of states of SnO2 doped with Gd in different ratio in Fig. 3 (b)-(d), we can be see that the new peaks in the region of −40eV are mainly caused by the 6s state of Gd, and the contribution of the energy level in the deep orbit to the conductivity is small, so it is not discussed. The valence bands all cross the Fermi level, which indicates that the doping of rare earth element Gd results in stronger interactions between different atoms, the distance from the excitation from the valence band to the conduction band decreases, and the required energy decreases, and the conductivity of SnO2 is enhanced. The d orbit of Gd atom and the s and p orbit of Sn appear hybridization
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
