Papers by Author: Yi Qiang Tu

Abstract: In order to improve the wear resistance of drill tools, stellite190 welding coatings were prepared by oxygen-acetylene flame welding technology. The abrasive wear behavior and wear mechanisms of the coatings were investigated in both dry and water friction conditions. The research results show that the wear losses of the coatings increase with the increase of loads and sliding speeds. The effects of sliding speeds on wear losses of the coatings become intense with the increase of loads. The wear losses of the coatings in water friction condition are bigger than those in dry friction condition. The main wear mechanisms of the coatings are micro-cutting and multi-plastic deformation wear in dry friction condition, and accompanied by stress corrosive wear in water friction condition.

Abstract: In order to improve the grinding performance and service life of electroplating composite coatings with high percent of hard abrasives, the composite coatings of Ni-Co/SiC were prepared by occlusion electroplating technology and their microstructure and tribological properties were studied. The research results show that the cathodal electric-current density in occlusion electroplating process and the SiC abrasive size have great influence on microstructure and tribological properties of Ni-Co/SiC coatings. The optimum value of cathodal electric-current density is 1 A/dm2 and the proper SiC abrasive size is about 20 μm, in which the Ni-Co/SiC coatings have excellent wear resistance and high grinding ability. The main wear mechanisms of Ni-Co/SiC coatings are micro-cutting and adhesive wear of matrix alloy, and micro-cracking wear and spalling of SiC abrasives.