Research On Preparation Process And Properties Of Ta-Mo Heat Resisting Coating By Magnetron Sputtering

As the rapid development of the modern industries especially in aviation andaerospace, the advantages of Ta and Mo series coating at high temperature performanceand mechanical properties have attracted lots of interests. Formerly the research on theprocedure for Ta-Mo coatings growth were absent and especially the little attention waspaid to the relationship between the microstructure of Ta-Mo coatings and its variousproperties. Therefore the thesis will focus on the analysis of microprocedure for sputteringand depositing Ta-Mo coatings, the research and exploration of the procedure for Ta-Mocoatings growth. The regular relationship between microstructure or component andproperty in order to reinforce the application research foundation and supply beneficialreference for better properites of Ta-Mo coatings.Ta-Mo coatings are deposited by co-magnetron sputtering in our topic. Themicrostructure, morphology, composition and growth orientation of Ta-Mo coating areaffected regularly by some parameters such as deposition time, gas pressure, substratetemperature, the third element and the sputtering power. At the same time, the properties ofTa-Mo coatings such as deposition rate, microhardness, cohesion and so on were alsostudied in this work. The intimate relationship between microstructures and properties ofTa-Mo coatings were analyzed, too.There are small island nucleation stage, the island joined stage, continuous coatingstage and the grain growth stage in the four stages of the growth of the coatings. Moreover,the complex relationship between the average roughness of particles and the substratetemperature are shown at different sputtering time. When sputtering pressure was changedfrom low pressure (0.2Pa) to high-pressure(1Pa and5Pa), Ta-Mo coating nucleation modelare changed from Moley-atomic nucleus merge model to Moley-atomic nucleus diffusionmodel and the growth mode changed from the island model to island-layer model. The best parameter on the crystallinity is the Si substrate, followed by Al, Cu and theSteel substrate in the last. The high-resolution electron diffraction images in SEM haveshown that the microstructure of coating on the Cu substrate is a multi-crystalline structure;The transformation from the amorphous to the crystal structure were promoted on thesubstrate heated process; Substrate heating process also can accelerate the growth of grainin Ta-Mo-Al coating. With the increase of sputtering power of Ta-Mo series coating, theaverage sizes of particles and surface roughness had also shown a trend of increased firstand then decreased.In the research on the properties of Ta-Mo coating, substrate material, sputteringpower, the third element, substrate temperature and other parameters are analyzed, whichare under the control of high-temperature oxidation, corrosion resistance and mechanicalproperties. Studies show that Si-substrate coatings are the best parameter in corrosionresistance and mechanical properties among the four substrate process; At roomtemperature, N and Al element did not enhance the accession of all Ta-Mo series of coatingperformance. However, the corrosion resistance and mechanical properties are improvedsignificantly on the condition of substrate heatingcoating. As the sputtering powerincreases from12.3w to26.8w, the corrosion resistance, oxidation and cohesion propertiesof the coating emerged the trend of raising and reducing afterwards, while themicro-hardness showed the opposite trend.