An advanced self-lubricating ceramic composite with the addition of core-shell structured h-BN@Ni powders. (April 2018)

• Record Type: Journal Article
• Authors: Wu, Guangyong; Xu, Chonghai; Xiao, Guangchun; Yi, Mingdong; Chen, Zhaoqiang; Chen, Hui
• Is Part Of: International journal of refractory metals & hard materials. Volume 72(2018)
• Page Start: 276
• Page End: 285
• Publication Date: 2018-04
• Subjects: Self-lubricating ceramics -- Electroless plating -- Ni coated h-BN -- Anisotropy -- Tribological behaviors; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2017.12.038
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: Aiming at the contradiction between tribological and mechanical properties of traditional self-lubricating ceramic composites, an advanced self-lubricating ceramic composite with the addition of pure-metal coated solid lubricant powders was developed in terms of microstructural modification of the traditional composites. Core-shell structured h-BN@Ni powders were synthesized by electroless plating technique with hydrazine hydrate as reducing agent. Al2 O3 /(W, Ti)C/h-BN@Ni composite made by adding h-BN@Ni powders exhibited notable improvements in microstructure and mechanical properties as compared with Al2 O3 /(W, Ti)C/h-BN composite made by adding uncoated h-BN powders. EDS and TEM analyses showed that the Ni shell particles in the Al2 O3 /(W, Ti)C/h-BN@Ni composite concentrated around the h-BN core grains and were located at grain boundaries or within the matrix grains. Due to their flaky structure, the h-BN grains had orientation distribution in the as-prepared ceramic composites, which resulted in anisotropies in mechanical properties and tribological behaviors. Dry sliding friction test revealed that the Al2 O3 /(W, Ti)C/h-BN@Ni composite had lower friction coefficient and higher wear resistance than the Al2 O3 /(W, Ti)C/h-BN composite. The different h-BN release modes caused tribological behaviors of the friction surface perpendicular to the hot pressing axis (HPA) to be better than those of the friction surface parallel to HPA. Highlights: An advanced self-lubricating ceramic composite containing pure-metal coated solid lubricants was developed. h-BN@Ni powders were synthesized using SnCl2 /alcohol as sensitizer and N2 H4 ⋅H2 O as reductant. Al2 O3 /(W, Ti)C/h-BN@Ni exhibited notable improvements in microstructure, mechanical properties and tribological behaviors. Anisotropies in microstructure, mechanical properties and tribological behaviors were investigated.