Preparation and properties of HfO2 coatings by chemical vapor deposition
HfO2 coatings with a thickness of approximately 8 μm were prepared on the refractory metals Mo surface by using chemical vapor deposition(CVD),and the reaction process of CVD HfO2 was thermodynamically analyzed by HSC Chemistry.The microscopic morphology,self-oriented growth and nanomechanical properties of HfO2 coatings were analyzed,and the bonding force of the coatings with the substrate and thermal shock resistance were tested.The results show that the HfO2 coating is well bonded to the substrate,and no macroscopic flaking occurs on the surface of the coating after 100 cycles of thermal shock from 25 ℃ to 2000 ℃;the adhesion of the coating is about 23 N as determined by the scratch test;the average emissivity of the surface of the coating is 0.48 in the band of 2.5-5 μm,which improves the average emissivity of Mo in the band by nearly 5 times.
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