The Study On The Preparation And Performance Of PS45-CuAl8 Pseudo-alloy Coating

The intention of this thesis is preparing a new Pseudo-alloy used in brake system by arc spray. The new coating will have comprehensive advantages in cost, performance of high temperature oxidation and wear resistance, besides, have good thermal conductivity.PS45 shows excellent performance of high temperature oxidation and wear resistance, but expensive. Aluminum bronze have low cost and show good performance.In order to use low cost and high efficiency arc spray have, we prepare PS45-CuAl8 Pseudo-alloys coating by HAVV with PS45 and CuAl8. Through this research, there will be a deeper understanding of how performance decided by the structure of Pseudo-alloys coating prepared by HAVV. There also will be a new idea for research and application of other Pseudo-alloys coatings.Researching the impact of different substrate temperature on performances of Pesudo-alloy coating. Comparing the capability of high temperature oxidation resistance of CuAl8, PS45 and Pseudo-alloy by high temperature cyclic oxidation tests. Analyzing phase changes, Surface morphology, element distribution changes by XRD, SEM and EDS, respectively. Comparing wear losses and Friction coefficient of the three kinds of coatings by wear tests and analyzing the wear mechanism by SEM.The appropriate substrate temperature is 250℃when prepare PS45-CuAl8 Pseudo-alloy. Pseudo-alloy show much higher temperature oxidation resistance than CuAl8 and only slightly lower than PS45. The oxide film between the original PS45 and CuAl8 improve high temperature oxidation resistance of Pseudo-alloy at 600℃oxidation test. At 800℃oxidation, due to infinite immiscible between Cu and Ni, good diffusion of Ni, diffusion of Cr to the lateral surface of the original CuAl8, the oxide film with better oxidation resistance form. High temperature oxidation resistance of PS45 is also enhanced because of diffusion of Ni.The wear loss of Pseudo-alloy is very close to PS45 and far less than CuAl8. In the 100N, 60min wear, the wear type of CuAl8 is abrasive wear and adhesive wear. There is only a small amount of compression on PS45 surface. The wear types of CuAl8 and PS45 are both in Pseudo-alloy. The friction coefficient of Pseudo-alloy is the most volatile because of alternate splicing structure. PS45 plays an anti-wear role in Pseudo-alloy. In the 200N, 20min wear, there is fatigue wear in CuAl8 and minor spalling in PS45. The wear resistance of Pseudo-alloy is very close to the PS45. The surface deformation reduced pressure. CuAl8 part play a supportive role and PS45 play a supportive role because of high hardness.