To understand the structure and performance of Ni base coatings on 18Cr2Ni4WA steel, the key techniques of plasma arc cladding method are introduced. Microstructure and microhardness of the coating clad were analyzed by using Vickers hardness tester,scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).Results show that the phase of the coating is composed of γ-Ni solid solution， nickel boride Ni3B，carbide Cr27C6 and Cr2B3 type chromium boride. The coating has no cracks and does not exhibit porosity, the bonding between layers is compact and the boundaries are not observed. The coating is featured by a homogenized microstructure; small grain and no evident heat-affected zone.

In order to solve the restoring problem of the high-strength steel accessories on the airplane, the feasibility study about restoring the high-strength steel accessories by electro-brush plating has been done. The restoring technics was discussed, furthermore, we test the rigidity, binding force and abrasion resistance of the parts after restoring. It indicates that the restoring technology owns many advantages, such as simple technology flow, convenient operation, low cost, strong binding force between the coating and substrate and good abrasion resistance, which could meet the request of the use completely. So it is worth extending.

In order to verify whether the coating can meet the stringent requirements of the ship’s long sailing cycle, harsh environment, and various unfavorable factors such as fire conditions, physical and mechanical performance tests, endurance tests, and Micro and micro tests of the three coating samples were carried out. The hardness of the ZS2000, ZS hybrid and ZS1000 coatings measured by the experiment were ⩾8H, ⩾7H, ⩾3H, respectively; the thermal conductivity values of the three coatings are very low, respectively 0.074 W/(m·K), 0.034 W/(m·K) and 0.025 W/(m·K), which can meet the requirements of the engine in unexpected flame environment; the original adhesion of the coating is the best, but the adhesion of the coating is reduced after the damp heat cycle and the salt corrosion at room temperature, and the salt spray resistance, damp and heat resistance of the coating are good, and no obvious defect is observed; TG experiments have found that the remaining percentages of the three coatings ZS1000, ZS2000, and ZS hybrid are 85.29%, 80.72% and 77.90% respectively. The thermal stability of ZS1000 is the best, and the three coatings have the best remaining balance. The difference is not large, so they all have good thermal stability. Analyzing the results of a series of performance tests, it is found that the comprehensive performance of the ZS hybrid coating is better than that of the ZS2000 and ZS1000 coatings.

In order to improve the repairing quality of aircraft envelope of the aluminum alloy LY12， the cerium conversion coating technology was studied by using the surface modification technique. Principle experiment was on the basis of aviation repair technological requirement, refers to the related technique, through examination of corrosion resistance and wear resistance performance of cerium conversion coating, the principal composition of the formula for making cerium conversion coating:Ce(NO3)3 + KMnO4+ Ce-1 (chemical additive), In order to determine each composition of the formula and the technology parameters scientifically, L9(34) orthogonal testing method was adopted, and the formula of surface modification solution was optimized, the technological conditions for making cerium conversion coating on the surface of aircraft envelope were determined. Results of corrosion resistance and wear resistance of the cerium conversion coating on the surface of the aluminum alloy LY12 aircraft envelope obtained by the new technology showed: 1. On the given test conditions, the best content of each chemical composition in the formula of modification solution for making cerium conversion coating on the surface were: l.Ce(NO3)3：14g/L,KMnO4：1g/L,addictive Ce-1:0.3g/L；Main technology parameters were ：pH=1.5～2.7;temperature：20°C；time:15~25 min.；2. Under the same test condition, the corrosion resistance of surface of the cerium conversion coating obtained in test modification solution was better than Alodine 1001 obtained from Bombardier Corporation of Canada, and can meet the repairing demands of Aircraft Envelope.