Evolution Characteristics of Advanced Nonferrous Metal Industry Patent Cooperation Network in China from the Perspective of Multilayer Network

The advanced nonferrous metal industry is a national strategic emerging industry, and its innovation ability is crucial to the transformation and development of downstream industries such as aerospace, rail transit, electronic information, and automobiles to the high end of the industrial value chain. The research on the evolution characteristics of its cooperative network is beneficial to the research on the mechanism of improving the innovation capability of the industry. Based on the cooperative invention patent application data in 2002-2020, using the social network analysis method and Gephi 0.9.2 visualization to construct a patent cooperation network and knowledge network, this paper analyzes the overall characteristics and evolution law of the patent cooperation network in the advanced nonferrous metal industry. It is found that, first, the structure of the innovation network in China's advanced nonferrous metals industry is becoming more and more complex. The scale of the cooperation network and knowledge network is increasing, and the small world is obvious. Second, some innovation subjects, as key nodes, play the role of "bridge" and grasp the general direction of technology. The structure of the key nodes in the network has changed, and the cooperative innovation network of industry-university-research has gradually evolved from enterprise-led to university-led. Third, the number of technical categories has increased and the depth of technology has been enhanced in China's advanced nonferrous metal field. Hot technical fields are characterized by high intensity, wide range, and stable advancement. Based on the research findings, some suggestions and enlightenment are put forward to promote the development of the advanced nonferrous metal industry.