| Diamond film with good adherent was deposited by Chemical Vapor Deposition (CVD) method on the soft polycrystalline copper substrate in this thesis. Microwave Plasma Chemical Vapor Deposition (MPCVD) apparatus manufactured in our own country was used for the preparation of diamond film. Influences of different interlayers on the adhesive properties were studied in detail. The results show: using a proper interlayer is a good way to enhance the adhesion between the diamond film and the substrate.Influences of varied parameters during the preparation process on the adhesion property between diamond film and copper substrate as well as diamond film quality were also studied in this thesis.Optimizing the parameters can enhance the nuclei ratio during the deposition of the diamond film,thus the crystal size is reduced and the quality of the film is improved.Reducing the thermal stress between film and substrate during the descent temperature process and improving chemical bonds combination is a key problem to enhance thee adhesion. Interlayers were used in this paper to release the thermal stress. Simply using Ti or Mo interlayer showed unobvious effect on the improvement of adhesion and diamond film would fell off from this single interlayer. Then Ti-Mo two layers structure was experimented and adhesion could be improved to some extent. However, shedding was still existed in this structure. The non-shedding region was examined by Luoshi rigidity instrument and results showed that diamond film fell off smashing out of the impress region. On the base of the above experiment, three-layer structure (Al layer was sandwiched between Ti-Mo layers) interlayers were used as substrates of diamond film deposition. Results showed that adhesion between film and copper substrate could be greatly improved using such interlayers. Impress method examination showed that diamond film crashed but not shed at the region of around impress. Varied compounds(Ti8CuAl23,Ti3AlC,Al2Mo3C,Al3Ti,Al3Mo,Mo2C )formedbetween film and substrate could be examined by X-ray diffraction measurement. Chemical bonds combination because of the existence of such kinds of compounds could greatly improve the adhesion property.Using three-interlayer structure, the influence of interlayer thickness, ultrasonic pretreatment in diamond micropowder (with different granularity)/ acetone solution, deposition temperature and time on the adhesion property was mainly studied. Results showed that Diamond (100) film could be deposited at the following experimental parameters: ultrasonic pretreatment in diamond micropowder solution of 250nm or 10 μ m; source gas CH41.2sccm/H2100sccm; deposition pressure 6.0Kpa; deposition temperature and time 850℃ and 8h. Diamond films with average size 0.9 μ m and 1.3 μ m were respectively obtained at ultrasonic pretreatment with 250nm and 10 μ m. Diamond (100) could be gradually transited into diamond (111) at the deposition temperature 850℃, 880℃ and 910℃ respectively. And diamond grains size was gradually reduced and showed pyramid shape. Diamond crystal grain size was increased with the deposition time. At the same deposition condition, compared to Ti(20min)-Al(5min)-Mo(5min) substrate, using Ti(10min)-Al(5min)-Mo(5min) as substrate could obtain worse adhesion property. However, when using Ti(20min)-Al(5min)-Mo(5min) -Ti(20min)-Al(5min)-Mo(5min) as substrate, it also could be obtained better adhesion property, which showed that interlayer thickness could not be too small. The optimum interlayer thickness for good adhesion property was still uncertain if only by impress method and should be further studied. |
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