表面技术2025，Vol.54Issue(3)：71-79,9.DOI:10.16490/j.cnki.issn.1001-3660.2025.03.005
Nb对激光熔覆NiCrMo/WC涂层组织和耐磨性能的影响
Effect of Nb on the Microstructure and Wear Resistance of Laser-clad NiCrMo/WC Coatings
摘要
Abstract
The brake disc is the key to ensure the safe operation of high-speed trains,and it is susceptible to wear and failure in the service process.The preparation of metal-based ceramic composite coatings by surface strengthening techniques such as laser cladding has become one of the ways to improve the wear resistance of material surfaces.In the braking process,the wear load and wear frequency of the brake disc increase in the transitioning from conventional braking to emergency braking,so it is valuable to study the wear mechanism under different wear conditions. In this work,NiCrMo/WC-xNb(x=0％,3％,6％,9％)composite coatings were prepared by laser cladding technology,in which NbC-reinforced phases were generated in situ within the coatings and synergistically strengthened with WC to enhance the wear resistance of the coatings.X-ray diffractometer(XRD)and scanning electron microscope(SEM)were used to study the effects of Nb content on the physical phase composition of the coatings as well as the microstructure.The nanoindentation test was used to characterize the hardness and elastic modulus of different microstructures within the coatings.The wear resistance of the coatings under different wear conditions was investigated by adjusting the wear load and frequency. The results showed that the physical phases of the composite coatings mainly included γ-Ni and σ-CrMo matrix phases,along with carbide phases such as NbC,WC,MoC,and Cr23C6.As the Nb content increased,the peaks of NbC gradually enhanced,while the peaks of carbides such as Cr23C6 weakened.With the increase of Nb content,the dendritic microstructure within the coatings was refined,accompanied by the generation of tetragonal and petal-shaped NbC-reinforced phases.The hardness(21.69-10.17 GPa)and elastic modulus(457.95-293.32 GPa)of WC,NbC,and matrix phases were distributed in a gradient,with softer phases experiencing initial cutting by the abrasive ball during the wear process.This provided effective protection to WC,reducing breakage during wear.The synergistic reinforcement of NbC and WC-enhanced phases endowed the coatings with a stronger ability to resist plastic deformation,significantly improving the wear resistance.The comprehensive analysis revealed that the hardness and wear resistance of the coatings increased with the addition of 9％Nb,reaching 67HRC,so the wear volume decreased by an average of 30％under different loads compared to that of coatings without Nb.The coefficient of friction remained stable between 0.4 and 0.5 at various wear loads and frequencies with the inclusion of 9％Nb.The wear mechanism of the coatings was found to transition from adhesive wear and abrasive wear to abrasive wear at a 30 N load.In comparison,at a 50 N load,the primary wear mechanism was identified as abrasive wear.Additionally,an increase in wear frequency resulted in elevated wear and decreased wear resistance of the coatings. In conclusion,the NiCrMo/WC-Nb composite coatings are prepared by laser cladding technology,and the NbC-reinforced phase is generated in situ in the composite coatings,which can synergistically strengthen the coatings with the WC particles and effectively improve the wear resistance of the coatings under different wear loads.关键词
激光熔覆/NbC/WC/协同强化/摩擦磨损Key words
laser cladding/NbC/WC/synergistic strengthening/frictional wear分类
矿业与冶金引用本文复制引用
成伟琦,崔洪芝,周明昊,王辰宇,吕玉君..Nb对激光熔覆NiCrMo/WC涂层组织和耐磨性能的影响[J].表面技术,2025,54(3):71-79,9.基金项目
国家自然科学基金联合基金(U2106216) （U2106216）
国家自然科学基金重点项目(52331004) （52331004）
山东省基金重大基础研究项目(ZR2022ZD12) （ZR2022ZD12）
驻鲁部属高校"十四五"服务山东重点建设项目(2023ZLGH05) （2023ZLGH05）
山东省重点研发计划JMRH项目(2022JMRH0202) （2022JMRH0202）
泰山学者攀登计划(tspd20230603) National Natural Science Foundation of China(U2106216) （tspd20230603）
National Natural Science Foundation of China(52331004) （52331004）
Natural Science Foundation of Shandong Province for Major Basic Research(ZR2022ZD12) （ZR2022ZD12）
Major-Special Science and Technology Projects in Shandong Province(2023ZLGH05) （2023ZLGH05）
Key R&D plan of Shandong Province(2022JMRH0202) （2022JMRH0202）
Taishan Scholarship of Climbing Plan(tspd20230603) （tspd20230603）
