| SONG Housheng,KONG Lingjie,ZHANG Weiping,ZHANG Feng,WANG Zexin,CHEN Liangyu,ZHANG Jun,Dobuvyy，Oleksand,LU Sheng.Optimizing of Process Parameters of Atmospheric Plasma Sprayed Alumina Coatings by Orthogonal Experimental Design[J],54(7):235-246, 259 |
| Optimizing of Process Parameters of Atmospheric Plasma Sprayed Alumina Coatings by Orthogonal Experimental Design |
| Received:August 16, 2024 Revised:January 02, 2025 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2025.07.020 |
| KeyWord:atmospheric plasma spraying technology alumina ceramic coating coating performance optimization orthogonal experimental design |
| Author | Institution |
| SONG Housheng |
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Jiangsu Zhenjiang , China |
| KONG Lingjie |
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Jiangsu Zhenjiang , China |
| ZHANG Weiping |
HFYC Zhenjiang Additive Manufacturing Co., Ltd., Jiangsu Zhenjiang, China |
| ZHANG Feng |
HFYC Zhenjiang Additive Manufacturing Co., Ltd., Jiangsu Zhenjiang, China |
| WANG Zexin |
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Jiangsu Zhenjiang , China |
| CHEN Liangyu |
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Jiangsu Zhenjiang , China |
| ZHANG Jun |
Kunshan Inspection and Testing Center, Jiangsu Kunshan , China |
| Dobuvyy，Oleksand |
School of Materials Science and Engineering, Admiral Makarov National University of Shipbuilding, Mykolayiv 54025, Ukraine |
| LU Sheng |
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Jiangsu Zhenjiang , China |
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| Abstract: |
| Atmospheric plasma spraying technology has emerged as a prevalent surface modification technique due to its straightforward operation, low cost, and broad material applicability. Alumina ceramic material, characterized by its outstanding hardness, stability, and electrical insulation properties, has demonstrated significant application potential. Nevertheless, in the plasma spraying process, the interaction among several parameters exerts a decisive influence on the coating properties. The impacts of spraying current, argon flow rate, spraying distance, and preheating times on the microstructure and mechanical properties of the coating were examined through orthogonal experimental design. The internal relationship between coating temperature and coating properties was disclosed by monitoring the temperature variation of the coating and the substrate during spraying with a thermocouple. In the experiment, GCr15 bearing steel pre-cut to the appropriate size was chosen as the base material, and the surface oil and oxide were eliminated through sandblasting pretreatment. Subsequently, a composite coating composed of a Ni5Al bonding layer and an Al2O3 working layer was fabricated on the substrate surface via plasma spraying technology. On the back of a 50 mm×50 mm×8 mm plate of GCr15 bearing steel, a temperature-measuring plate for inserting and fixing armored thermocouples was fabricated by employing the EDM drilling process. The thermocouple was connected to the temperature recorder, which was utilized to record the temperature of the substrate and the coating during the spraying process and investigate its temperature rise pattern. The phase composition, microstructure, porosity, hardness, and bonding strength of the coating were characterized with an X-ray diffractometer, a metallographic microscope, a hardness tester, and a universal testing machine. Through range analysis, the influence of the selected parameters on coating properties was quantified, and a set of plasma spraying parameters was optimized by considering the porosity, hardness, and bonding strength of the coating. The results indicated that during 20 spraying cycles, the coating temperature gradually rose with the plasma flame sweep. The rising rate of the coating temperature decelerated in the middle spraying stage and reached a state of heat balance in the later spraying stage, and the coating temperature tended to stabilize. The heating rate of the coating was primarily affected by the argon flow rate, while the equilibrium temperature was mainly influenced by the current and the argon flow rate. The influence of preheating times on the equilibrium temperature of the coating was insignificant. The prepared Al2O3 coating mainly consisted of α-Al2O3 and γ-Al2O3. Since the transition from γ-Al2O3 to α-Al2O3 required crossing an energy barrier, the transition was not fully accomplished within the studied heat input and coating temperature range below 600 ℃. The proportion of γ-Al2O3 was positively correlated with the melting degree of the powder, while a higher argon flow rate would reduce the proportion of α-Al2O3. The deposition efficiency of the coating was influenced by current, argon flow rate, and spraying distance. Among them, high current, argon flow rate, and spraying distance would significantly increase the coating porosity. The average hardness of the coating section was related to the melting state of the powder and showed a high positive correlation with the proportion of γ-Al2O3 and the coating temperature. The consistency of the hardness of the coating was high, and the subsequent deposition of the coating had no obvious tamping effect on the previous coating. Taking into account the porosity, hardness, and bonding strength of the coating, this study ultimately determined the optimal process parameters of the atmospheric plasma spraying alumina coating:current 650 A, argon flow rate 30 L/min, spraying distance 120 mm, and preheating twice. This combination of parameters not only ensured the high quality of the coating but also provided a reliable technical support for industrial applications. |
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