YG6金刚石涂层刀片衬底真空渗硼预处理新技术研究

本文研究了真空渗硼预处理硬质合金基体的表面组织、形貌、粗糙度，并在处理过的YG6刀片基体上，用强电流直流伸展电弧等离子体CVD法沉积金刚石薄膜涂层。结果表明，真空渗硼预处理不仅可以有效的消除或控制钴在金刚石沉积时的不利影响，而且，还显著粗化硬质合金基体表面。因此，提高了金刚石薄膜的质量和涂层的附着力。     

含硼聚晶金刚石复合片(B-PDC)的研究

利用国产六面顶压机,在高温高压的条件下,采用黏结剂Co熔渗催化方法合成含硼聚晶金刚石复合片。对加入不同体积分数的含硼金刚石合成的样品进行性能测试,最后对样品的性能测试结果进行讨论分析,并对聚晶金刚石层微观结构做了扫描电镜观察和XRD物相分析。结果表明:样品的抗冲击韧性和耐热性比普通金刚石复合片有显著提高,当添加含硼金刚石微粉体积分数为2a%～3a%时综合性能最好。     

Fracture in CVD diamond

The fracture behaviour of thick, textured films of chemical-vapour-deposited diamond is discussed with particular emphasis on the influences asserted by the polycrystalline microstructure. Cracking is investigated on two different scales, firstly where it is large in that it traverses many grains and pertains to the fracture of the bulk. The second is where the fractures are localised, resulting from repeated small particle impacts and the mechanisms of material removal at the grain-size-scale are elucidated. The behaviour at this smaller level can be rationalised in terms intermediate to bulk fracture and that observed in single crystal diamond. The effects of grain size, grain boundaries, crystallographic orientation, twinning, internal stresses and pre-existing flaws are discussed. A new value for the fracture toughness is calculated and the gravimetric erosion rate for different surface orientations measured.     

微晶/纳米金刚石复合涂层的沉积与表征

采用偏压增强热丝CVD(HFCVD)法,通过引入惰性气体Ar,在经过甲醇新预处理方法处理后的硬质合金衬底表面成功沉积了微晶/纳米金刚石复合涂层。对金刚石复合涂层的表面形貌、成分、表面粗糙度进行了分析和研究。研究结果表明:新的预处理方法能够提高金刚石薄膜与衬底之间的附着强度。Ar的引入使得金刚石薄膜二次形核率更高,颗粒也更加细小,纳米金刚石复合涂层不但具有高的附着强度,而且具有非常低的表面粗糙度。对于拓展纳米金刚石涂层在精密加工领域中的应用具有一定的作用。     

A comparison on core drilling of silicon carbide and alumina engineering ceramics with mono-layer brazed diamond tool using surfactant as coolant

Core drilling with diamond tool is an efficient method for machining of holes in engineering ceramics. A comparative study on core drilling of silicon carbide and alumina engineering ceramics with mono-layer brazed diamond tool was carried out. Two surfactant (anionic type 1631 and nonionic type OP10) water solutions were used as coolant in core drilling. The effect of the coolant׳s type and concentration on drilling torque and drilling efficiency were also investigated. The morphologies of machined surface of ceramics and the wear of diamond grits were examined. According to the results, the anionic surfactant 1631 water solution produces a lower drilling torque and higher drilling efficiency than that of nonionic OP10. Both silicon carbide and alumina demonstrate a ductile regime of material removal under the lower maximum undeformed chip thickness (0.08 mm). The wear of brazed diamond grits for drilling of silicon carbide is much severer than that of alumina.     

Ni-P-金刚石化学复合镀研究工艺对镀层硬度的影响

在镍磷化学镀的基础上,研究了微米、纳米金刚石化学复合镀工艺。采用正交试验方法,研究化学镀液、金刚石种类与浓度、表面活性剂种类与含量以及热处理温度等因素对镀层显微硬度的影响。结果表明:对镀层硬度影响明显的因素依次为金刚石种类、表面活性剂种类、热处理温度和表面活性剂含量,而镀液种类和金刚石浓度对镀层硬度的影响较小。最佳工艺为:金刚石为纳米金刚石灰粉,添加阴离子表面活性剂,热处理温度为350℃,表面活性剂含量为1∶10,选用化学镀液B,金刚石浓度为6.0g/L。     

精磨高硬脆材料表面形貌分析及工具浓度的选择

文章对比了不同浓度的W40、W12、W7等粒度金刚石砂带精磨玛瑙时的工件表面形貌参数、以及达到最佳粗糙度所需的磨削时间。实验结果表明,W40砂带金刚石浓度应选择13.5%～16%（vol%）,W14砂带金刚石浓度应选择11%～13.5%,W7砂带金刚石浓度应选择≤11%。     

聚晶金刚石复合体的研究进展

介绍了国内外对聚晶金刚石复合体的研究状况, 如衬底与复合界面的研究、原材料的选择、添加剂的种类、金刚石表面石墨化、织构细化以及烧结工艺等对聚晶金刚石复合体性能影响的研究。并综述了影响聚晶金刚石复合体性能的相关因素。     

金刚石中子探测器稳定性和探测效率测试

介绍了金刚石中子探测器主要性能的测试方法。采用14 MeV氘氚中子测试了金刚石中子探测器的稳定性和探测效率,实验结果表明探测器性能稳定,中子探测效率ε_E=8.00×10~(-5)(±9.38%)counts/n·cm~2。SuperMC蒙卡软件对探测效率进行模拟计算,计算结果ε_C=8.69×10~(-5)(±3%)counts/n·cm~2,不确定度范围内认为二者一致。