F. Jianjun, Z. Li, Y. Shi, Beijing University of Technology, China, Beijing, China; J. Jiang, Beijing University of Technology, Beijing, China
This study is based on the effects of micro-and nanostructured feedstock on synthesis and characterization of metal-ceramic composite coatings by arc spraying. The size and morphology, changes in chemical compositions, grain state and microstructure of particles processed by AS of comprising micro-and nanostructured powders is characterized and compared to which of the conventional feedstock. And mechanisms governing the development of the composite coatings are discussed. The melting degree of particles, the thickness of splats, coatings microstructure and phase compositions were systematically investigated by means of optical microscopy(OM), 3D Surface Profiles, SEM, EDS, XRD and hardness testing. Results show that refining the TiB2 size to microscale or add nanoscale Al2O3 is of special importance for the development of densified coatings since volume fraction of the solid phase, ceramic particles rebound, deposit efficiency and splat characteristics depend on the feedstock size. The conclusion suggest that micro-and nanostructured powder can improve microstructure, bonding strength and toughness of coatings.
1.comparisons of the deposit eprocess and characters between conventional powders cored wire and micro-and nano powders cored wire showed that ceramic phase rebound existed in arc spraying, and TiB2 ceramic have oxidation phenomena in high temperature zone.
2.with ceramic powders size to micro- and nana scale, the state of particles melted, ceramic phase deposit efficiency and flatten ratio had incerased clearly, and which resulted in the wettablity of ceramic phase and metal matrix improved.
3.add micro-and nanostructured ceramic powders can optimize coatings microstructure and low porosity, but have little effect on the micro-hardness, improve the bond strentgh and toughness.
