Coating damages, such as cracks and spallation, always occur under high temperature gradient and its resulting residual stress level. This is why it is important and necessary to monitor and control the coating temperature during atmospheric plasma spray process. In this paper, a novel measurement approach for substrate and coating temperatures is presented. It is based on IR pyrometery combined to specific robot scanning trajectories in order to avoid harsh environment of spray workshops. The temperature-time evolution was continually detected and recorded during preheating, spraying and cooling stages and the two specific factors, periodic average temperature and standard deviation were adopted to evaluate the temperature variation and the fluctuation of the thermal cycle relevant to one robot scanning cycle based on the statistical method. These two factors were successful in describing the temperature variation during experimental processing sets. Finally, on the basis of experimental results of the influence of Z typed robot spray trajectory parameters, including spray distance, spray velocity and scanning step on coating temperature characterized by the two factors, an intelligent adaptive control of sprayed coating temperature was developed to obtain constant temperature cycles by means of adjusting robot trajectories, cooling, among other considered operating parameters. Excellent control performance is observed.

A new method was introduced to fabricate porous coating and to control its porosity by changing spray parameters. Two models were constructed to simulate the deformation of molten particle and the deposition process of splats on substrate. Considering the gap-pore, step-pore and shield-pore in the presented models, the influence of spray angle on the porosity of coating was mainly investigated. Besides, other spray parameters which influence porosity were analyzed, including the velocity of spray gun, particle velocity and particle size. Moreover, a new forming method of graded porous coating is discussed.

Atmosphere plasma spray and robot digital fabricating were integrated and presented to prepare the planar PEN and MOLB-type PEN SOFCs. On the basis of the spraying conditions optimized previously and the self-developed functionally graded powder feed system, two kinds of PEN cells were prepared. Then the microstructure and material components of the PEN cells were analyzed. The results show that graded layers were formed between the electrodes and electrolyte. Moreover, the material components and the porosity of the graded layers vary gradually. In particular, the porosities of the anode and cathode reach 32.74%, 32.24%, respectively. Using the AC complex impedance technology, the conductivity of the MOLB-type composite electrode is tested. As a comparison, the electrical conductivity of the MOLB-type composite electrode with the graded layers is larger than that without the graded layers.