## 2 Experimental Methods  
### Coating Preparation Process and Parameters  
In this work, conventional TBCs and EMAP TBCs were prepared by the APS method. Figure 1 shows the schematic diagram of the two coating preparation processes, where Figure 1a is the conventional coating preparation process, and Figure 1b shows the preparation process of EMAP TBCs by adding a second-phase powder feeder on the basis of conventional plasma spraying. A total of 15-45 \(\upmu\)m 7-8 yttria-stabilized zirconia (YSZ) powder was selected as the conventional TBCs ceramic layer. EMAP TBCs select 15-45 \(\upmu\)m 7-8 YSZ powder to prepare the coating matrix, which ensures that the coating has high fracture toughness. And the second-phase MAP is introduced to embed it into the conventional coating matrix so that the coating has a higher porosity. In particular, the second-phase MAP is an 8 YSZ spray sintered powder with a special pore structure. The 1-5 \(\upmu\)m 8 YSZ powder was agglomerated into 8 YSZ MAP with a particle size of 15-45 \(\upmu\)m by spray granulation. After agglomeration, only slight sintering was performed to maintain a loose and porous structure. As shown in Figure 2, according to the different microstructure of the powder particles, they can be divided into fused and crushed (FC) powder (China Chengdu Huayin Powder Technology Co., Ltd., Chengdu, China) and MAP powder (China Tianjin Micro-Nano Technology Co., Ltd., Tianjin, China). By observing the microstructure SEM images of the two powders, it can be clearly seen that the MAP has a special porous structure. NiCrAlY powder was selected as the metal bonding layer, and the sprayed powder was solid and spherical. The alloy substrate employed for preparing the sample is IN7388 nickel-based alloy with model GH5188. The diameter of the alloy substrate is 25.4 mm, and the thickness is 6 mm.  
In this work, the preparation of thermal barrier coating test equipment used an atmospheric plasma spraying (APS, Sulzer Metco Co., Ltd., Winterthur, Zurich, Switzerland) system with an F4 MB-XL plasma spray gun (F4, Sulzer Metco Co., Ltd., Winterthur, Zurich, Switzerland). The coating samples were prepared in a normal temperature and pressure environment. During the spraying process, argon (Ar) was employed as the main gas and hydrogen (H\({}_{2}\)) as the auxiliary gas. The main gas flow rate was controlled at 30 L/min, the auxiliary gas flow rate was controlled at 8 L/min, and nitrogen (N\({}_{2}\)) was employed as the powder carrier gas. The spray gun moving rate was set to 500 mm/s, the carrier gas flow rate of the first powder feeder was 2 L/min, and the second powder feeder rate was set to 3 L/min. To explore the influence of different spraying parameters on the microstructure and service life of EMAP TSCs, 10 groups of different spraying parameters were set up by the control variable method to prepare conventional thermal barrier coatings and EMAP TSCs. As shown in Table 1, the first powder feeding rates of groups 2, 3, and 4 were 12, 16, and 20 g/min, respectively, to explore the effect of relative powder feeding rate on the microstructure and service life of EMAP TSCs. The distance between the two powder feeders was set to 35, 40 and 30, respectively, in groups 3, 5 and 7 to explore the influence of the distance between the powder feeders on the microstructure and service life of EMAP TSCs. Different types of first-phase powders were set up in groups 2, 6, 9, and 10 to explore the effect of powder types on the service life and microstructure of EMAP TSCs. The first-phase powder of the 2 and 6 group is FC powder, and the first-phase powder of the 9 and 10 group is a MAP powder. We set 1, 2 and 8, 9 groups to explore the thermal cycle  
Figure 1: Coatings preparation process diagram. (**a**) Conventional TSCs preparation process; (**b**) EMAP TSCs preparation process [20].  
Figure 2: Micromorphology of two 8 YSZ powders. (**a**) FC; (**b**) MAP.  
life of conventional coatings and EMAP TBCs and the effect of powder type on the life of conventional coatings.