Study of rapid and direct thick coating deposition by hybrid plasma-laser manufacturing

As a new direct and rapid thick coating technology, the hybrid plasma-laser deposition manufacturing (PLDM) is described in this paper. In order to research the influence of the laser on the plasma arc beam shape and the microstructure of surface coating and mechanical properties of surface coating layers, a high speed CCD camera was used to obtain a picture of the plasma arc. Then the figure of the plasma arc has been obtained through dealing with the plasma arc picture by Gauss-Laplace arithmetic operators. In this study, the laser beam generated by a Q-switch Nd: YAG laser machine enters into the plasma arc beam as additional heat energy. The results of this study are summarized as follows: (1) The diameter of the plasma arc beam decreases, the depth of the molten pool increases and the width of the molten pool decreases. (2) The arc starting becomes easier. (3) The distribution of the elements in the surface coating deposited by PLDM is uniform. (4) The mechanical properties of the thick coating layers manufactured by PLDM are better than those deposited by the plasma deposition manufacturing as a whole. (c) 2006 Elsevier B.V. All rights reserved.