| The erosion wear is one of common form of wear in the modern industry, whichis an important reason for materials damage or failure. Studies showed that usingnitride coatings is an effective way to improve materials erosion resistance. In thisthesis, By using finite element method and experiment research, the erosion wearperformance of nitride coatings material have been studied, the main contents andconclusions were as follows:By using indentation fracture mechanics, the erosion on brittle materials wereanalysised and the brittle materials removal model were also established.Based on thefinite element method, a kind of five particles FEM model for nitride coatings erosionwear was established by using ANSYS/LS-DYNA software and the erosion wearperformance of nitride coatings was analyzed.The influence of coating architecture (thickness, interlayer) on nitride coatingserosion wear performance were analysised, the results showed that the erosion rate ofthe coating decreases with increasing coating thickness, and the coating with theinterlayer showed better anti-erosion wear resistance.The influence of coating mechanical properties (hardness H, elastic modulus E)on Nitride coatings erosion wear performance were analysised, the results showed thatthe erosion rate of the coating decreases with increasing elastic modulus anddecreases with increasing the H/E and H3/E2value, the two mechanical properties ofhardness H and elastic modulus E of nitride coatings will synthetically influence itserosion wear performance.The influence of the elastic modulus of the substrate on nitride coatings erosionwear performance were analysised, the results showed that when the elastic modulusof the substrate is equal to the elastic modulus of the coating, the nitride coatingsshowed the best erosion wear resistance.The influence of environmental parameters (impact angle, impact speed) onnitride coatings erosion wear performance were analysised, the results showed that theerosion rate of the coating is increased with the increase of impact speed and impactangle, the erosion rate of coating obtained the maximum when the impact angle is90°, the nitride coatings exhibited a typical erosion characteristics of brittle material.The influences of abrasive particle properties (size, shape, hardness) on nitridecoatings erosion wear performance were analysised. The results showed that the erosion rate of Nitride coating is increase with the increase of the particles size andhardness. When the ratio of abrasive particle hardness to coatings hardness Hp/Ht>1,,the coating withstand hard particle erosion and the erosion rate is relativelyhigher,When Hp/Ht<1, the erosion rate is relatively lower due to the coating mainlyunder soft particle erosion.Through analyzing the influence of abrasives particle shapeon nitride coatings erosion wear, the results showed that the erosion ability ofhexagon prism abrasive for coating is about4times higher than the spherical abrasive.Experimental studies on the erosion wear behavior of TiAlN coating wereconducted with a dry blasting machine tool. The experimental results showed that theerosion rate of TiAlN coating is about four times lower than WC/TiC/Co substrate.The macroscopic morphology of TiAlN coating was observed by a surfaceprofilometer, The experimental results showed that TiAlN coating exhibited a typicalerosion characteristics of brittle material. the eroded surfaces and fracture surfacemorphology of TiAlN coating were examined by scanning electron microscopy anderosive wear mechanism of TiAlN coating was analysised. It is concluded that themainly erosive wear mechanism of TiAlN coating is brittle fatigue fracture andmicro-cutting. |
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