Effects Of Electrical Parameter On Substrate Temperature Rising,Microstructure And Properties Of Ti Coating

In view of the objective fact that the substrate temperature rises continuously in the process of ion plating, the characterization based on the theory of quenching and tempering in metal heat treatment was proposed in this paper. Ti coatings were deposited on the quenched 40CrNiMoA and GCr15 by changing the electric field and the power supply mode, discussing the influences of electrical parameter on the substrate temperature rising and Ti coating, and achieving the good bearing capacity of substrate and the microstructure of coating.The results showed: with the same target power density, temperature distribution along the depth direction of substrate decreases showing straight line, then decreases slowly, and remains steady after. With the increasing of the target power density, substrate temperature rise entirely ,and the maxima of substrate temperature rising gradually increase, GCrl5 range from 160 ℃ to 441 ℃ 40CrNiMoA range from 305 ℃ to 526 ℃. At the same time ,with the evolution of target power density, combined with substrate temperature rising, the crystallization degree of the Ti coating enhances, the preferred orientation changes from (100) to the (110), the average grain size increases significantly from 9.3 nm to 22.5 nm, and the surface roughness declines first and then adds slightly. Also, the coatings is compressive stress, and internal stress releases with the elimination of micro-defects and lattice after the maximum of substrate temperature rising is more than 300 ℃.Thus, while target power density is 97.50 W/cm2(target current is 7.5 A) in DC field,40CrNiMoA, which has high tempering temperature, has no substrate softening, at the same time,the gas discharge is in the transition zone of the arc, the density of coating is high, the surface roughness is the smallest, achieving excellent matching between bearing capacity of substrate and microstructure of coating, and due to the relaxation of internal stress, the deposition rate increases obviously, reaching to 42.56 nm/min. Also, substrate softening can be avoided when target power density is 11.89 W/cm2 for GCr15, which has low tempering temperature, so that while pulse peak current is 15 A, pulse width is 2 ms, pulse frequent is 50 Hz, the substrate temperature rising can be effectively controlled. Also, the deposition morphology with fine particles is smooth, the hardness is 5.9 GPa, the plasticity index is 0.670, and the bonding strength meets the requirements as well,achieving the purpose of process design.