Preliminary studies on the main characteristics and transient heat shock performances of detonation sprayed tungsten coatings on 316 L steel substrates

• Published in: Surface & coatings technology Vol. 429; p. 127946
• Main Authors: Wang, Xingli, He, Minjun, Guo, Zongxiao, Wang, Fan, Zhou, Deli, Wu, Zhongxuan, Huang, Jianjun
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.01.2022; Elsevier BV
• Subjects: Atmospheric plasma spraying; Austenitic stainless steels; Bonding strength; Bulk density; Characteristics; Coatings; Deoxidizing; Detonation; Detonation spraying; Heat shock; Microhardness; Nuclear fusion; Oxygen content; Shock resistance; Spraying; Substrates; Transient heat shock; Tungsten; Tungsten coating; Transient heat shock; Detonation spraying; Atmospheric plasma spraying; Tungsten coating; Characteristics
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2021.127946

Detonation spraying (DS) method was used to deposit tungsten coatings on 316 L steel substrates for the potential usage of the first wall of blanket in nuclear fusion devices. The main characteristics and anti-transient heat shock performances of the DS-W coatings were studied and compared with that of the atmospheric plasma sprayed tungsten (APS-W) coatings. The results showed that the DS-W coating had a very dense structure with its porosity of about 0.97%. The oxygen content of the DS-W coating that roughly detected with an energy dispersive spectrometer was much lower than that of the APS-W coating and the initial tungsten powders. It was considered that this result should be due to the unexpectedly introduced W2C during the DS process. These W2C would act as deoxidation agent and decrease the oxygen content in the coating. The microhardness of the DS-W coatings was much higher than that of the APS-W coatings and the pure tungsten bulk. It was analyzed that the dense structure, the reinforcement by W2C and the fine-grained strengthening effect during the DS process were responsible for this result. Furthermore, the DS-W/steel specimens exhibited excellent bonding strength and transient heat shock resistance. After having been tested under 3.5 MJ/m2 of transient heat loads, the DS-W/steel sample was still on a good status without obvious damages. Besides, it was believed that the overall performance of the DS-W coatings should be further improved through appropriate post-processing methods. As a conclusion, the DS-W coating demonstrated outstanding properties and its great potential for the application in plasma-facing materials. •Tungsten coatings were deposited on 316 L stainless steel substrates by detonation spraying (DS) and atmospheric plasma spraying (APS) methods.•The main characteristics of the DS-W coating were studied which proved its much better overall properties than that of the APS-W coating.•The DS W/316 L coating specimens showed better performance under transient high heat shock tests than that of the APS ones.•The DS-W coating demonstrated its potential application in preparing or mending tungsten/steel-based first wall of nuclear fusion reactors.