Boron-doped Diamond-like Carbon Coating Preparation And Its Adhesion Research

DLC coating is amorphous carbon included a series of sp3 and sp2, it has high hardness, low friction factor, excellent wear resistance, good permeability and biocompatibility, so it caused wide attention in recent years as a new type of functional thin film materials. B-doped DLC can be made into BDD electrodes, it has high oxygen evolution potential, lower background current, high adsorption inertia and high physical and chemical stability, make it a good choice for electrochemical electrode. However, high internal stress, thermal unstability, high brittleness, not large deposition are flaws of DLC. Metal and nonmetal doped, multilayer structure are u sed to reduced the internal stress of DLC and improve the thermal stability; changing preparation method are used to make the large deposition come true; wear test under different conditions are used to obtain friction and wear mechanism. These solutions are based on “five thinking of composite coating”(composition deposition technology, coating composite diversity, nano-crystal structure, multilayer or gradient structure)Adhesion strength is a key factor in life of coating, is also the most fundamental factor of coating application value. The adhesion of DLC is weak, that become a problem for its further application. At present, elements doping 、 transition layer preparation 、 nano modulation are mainly used to improve adhesion. Research of boron- doped DLC focuses in terms of its electrochemical and biocompatibility, the mechanical properties studies few, studying boron-doped DLC performance can broaden its application.Magnetron sputtering prepared DLC are introduced in this paper. Firstly, prepared DLC on different substrate by rf magnetron sputtering, the effect of different substrate has been analyzed to the structure and properties of DLC. Then, DLC are prepared by closed field unbalanced magnetron in different graphite target, the microscopic morphology and structure are analyzed by atomic force microscopy, scanning electron microscopy, Raman spectroscopy and X-ray diffraction method, mechanical properties are tested by the nano indentation, scratch test, friction and wear.Finally, boron-doped DLC are prepared using solid boron as sputtering target, a lot of test ways are applied to analyse its structure and performance. The results showed that DLC prepared by closed field unbalance magnetron sputtering has more sp2, more high adhesion, lower friction coefficient than prepared by rf magnetron sputtering. Boron element make DLC more rough, more sp2, but a small amount of boron can make coating elastic modulus and hardness increased, adhesion raised a small scale, friction coefficient and wear rate reduced. But DLC elastic modulus, hardness and adhesion are greatly reduced added too much boron element.