金刚石薄膜涂层钻头加工高硬度钢的实验研究

DRILLING HIGH RIGIDITY GCr15 STEEL WITH DIAMOND MEMBRANE COATED DRILL BIT

为提高金刚石薄膜涂层的韧性,避免金刚石薄膜涂层脆性断裂,以自贡硬质合金厂生产ZK-10型号硬质合金钻头为基体,采用厚度大约为3μmTiC作为过渡层,在表面涂覆4μm-5μm厚度的金刚石薄膜制成金刚石薄膜涂层钻头。用于加工硬度为HRC61的经热处理的GCr15钢板,分别与未涂层硬质合金钻头、TiC-TiN涂层钻头对比,结果表明,金刚石薄膜涂层钻头由于加工速率高,摩擦发热量少,有效地避免了铁元素在高温下将金刚石转化石墨的作用,结果使用寿命比未涂层硬质合金钻头提高10倍以上,同TiC-TiN涂层钻头相比,初期加工性能明显优越,加工速率成倍数提高,但使用过程中,性能衰减更快,导致总体使用寿命同Tic-TiN涂层钻头相差不大。在表面喷砂处理中,金刚石薄膜涂层大部分易于脱落,剩余部分呈岛状分布,说明金刚石薄膜与基体的结合力分布很不均匀,这可能与金刚石薄膜的形核过程密切相关。

Diamond coated drills are prepared by depositing 4μm-5μm thickness diamond membranes on model ZK-10 WC alloy drills, 3μm thickness TiC is applied as transition to improve the tenacity of the coating. The coated drills are used to machine HRC61 high rigidity GCr15 steel board, then the performance is compared to WC and TiC - TiN coated drills. The result indicates that diamond coated drills avert the return of diamond into graphite caused by catalyzing of iron element, the machining life of diamond coated drills is 10 times longer than that of WC drills, and the machining velocity of diamond coated drills is remarkablely higher than that of WC alloy or TiC-TiN coated drills, but the machining capacity drops more violently than TiC - TiN coated drills along with the machining. Ultimately the machining life of diamond coated drills is about the same as that of TiC-TiN coated drills. The two kinds of coated drills are sandblasted to test the adherence of the coating, diamond membranes are torn off from the substrates mostly, the residual parts distribute in insular form, the cause is likely to be correlate with the nucleating process of CVD diamond.