Study On The Structure And Performance Of The Al-rich Al-Cr-O Films Deposited By Reactive Sputtering At Low Temperature

Corundum-type Al-Cr-O film own various excellent properities,which is similar to that of?-Al₂O₃.Corundum-type Al-Cr-O film has a wide application prospect in the fields of wear resistance coatings,electrical insulation coatings,diffusion barrier coatings and tritium permeation barrier coatings because of its high hardness at room temperature and high temperature,high electrical insulation,excellent chemical stability and low tritium permeability.The properities of the corundum-type Al-Cr-O film are closely related to the relative content of?-Al₂O₃ and?-Cr₂O₃.With the increasing of the content of?-Al₂O₃,the thermal stability,dielectric and insulation properties of the film will be improved accordingly.In this paper,RF reactive magnetron sputtering method is used to deposit Al₂O₃ films and Al-Cr-O films.The influence of the deposition parameters on the phase structure and properities of Al₂O₃ films deposited with Al target were investigated.And then the influence of the Cr content of target and substrate bias voltage on the phase structure and properities of Al-Cr-O films deposited with Al_xCr_100-x target?x=90,70,50?were studied.The results were shown as follows:When the O₂ partial pressure?9.09%,the stoichiometric Al₂O₃ films can be deposited.The main phase of Al₂O₃ films deposited with Al target at 490?540?is?-Al₂O₃,with a small amount of?-Al₂O₃,?-Al₂O₃ and amorphous phase.With the increase of temperature,the content of?-Al₂O₃ increases,and the content of?-Al₂O₃ and?-Al₂O₃ decreases,meanwhile the hardness and elastic modulus of the films also increases.The hardness and elastic modulus of Al₂O₃ film deposited at 590?are 20.3GPa and 204.6GPa,respectively.At 540?,the film deposited with Al₅₀Cr₅₀ target is composed of?-?Al,Cr?₂O₃ and?-Al₂O₃,and the film deposited with Al₇₀Cr₃₀ target is single-phase?-?Al,Cr?₂O₃ solid solution structure.The hardness of the films deposited with Al₅₀Cr₅₀ and Al₇₀Cr₃₀ target are23.2GPa and 23.8GPa respectively.The main crystal phase of the film deposited with Al₉₀Cr₁₀target is?-?Al,Cr?₂O₃,and there are a small amount of?-Al₂O₃and corundum phase Cr₂O₃ in the film,and the film has poor properities.The increase of Cr content in Al-Cr-O films is helpful to improve wear resistance.When the temperature is 540?,the Al-Cr-O films deposited with Al₇₀Cr₃₀ target at the substrate bias voltage of 0?-100V are all corundum-type Al-Cr-O films.When the substrate bias voltage is 0,the film is single-phase?-?Al,Cr?₂O₃ solid solution structure.With the increase of the substrate bias voltage,the content of?-Al₂O₃increases in the films,and the films are composed of?-Al₂O₃ and?-?Al,Cr?₂O₃.When the substrate bias voltage increases to-150V,the metastable phase?-Al₂O₃ appears in the film,and the film is composed of?-Al₂O₃,?-?Al,Cr?₂O₃ and?-Al₂O₃.The substrate bias voltage is helpful to increase the Al content in Al-Cr-O films.In the stoichiometric Al-Cr-O films deposited with Al₇₀Cr₃₀ target,the Al content in the films increases with the increase of substrate bias voltage.When the substrate bias voltage is-100V,the Al content in the film is as high as 79.5at.%,which is the corundum-type Al-Cr-O film with the highest Al content deposited at 540?reported at present.With the increase of the substrate bias voltage,the hardness and elastic modulus of film increase and the friction coefficient decreases.When the substrate bias voltage is more than-100V,the appearance of?-Al₂O₃ in the film leads to the decrease of hardness and elastic modulus,and the increase of friction coefficient.The Al-rich corundum-type Al-Cr-O film deposited at the substrate bias voltage of-100V shows the best mechanical properties and wear resistance with the hardness and elastic modulus of 28.1GPa and 245.6GPa,and the friction coefficients of the film with the Si₃N₄ ball and GCr15 ball are 0.58 and 0.61.