金刚石微粉和抛光液的制造工艺检测技术及应用(上)

金刚石微粉、金刚石抛光液的制造工艺、检测方法对它的质量有重要影响.文章重点介绍近年来发展较快的气流磨加工技术、抛光液制造技术和激光粒度检测技术.全面总结了颗粒粒度的各种定义及多种检测方法、常用化学反应,并对它们进行比较.指出影响产品质量的诸因素.     

金刚石微粉和抛光液的制造工艺检测技术及应用(下)

金刚石微粉、金刚石抛光液的制造工艺、检测方法对它的质量有重要影响.文章重点介绍近年来发展较快的气流磨加工技术、抛光液制造技术和激光粒度检测技术.全面总结了颗粒粒度的各种定义及多种检测方法、常用化学反应,并对它们进行比较.指出影响产品质量的诸因素.     

一种金刚石微粉冲击性能测定方法

冲击韧性(TI)是金刚石微粉质量的重要指标,本文采用激光粒度仪方法对不同粒度不同强度等级的金刚石微粉进行测试.结果 表明:激光粒度仪方法与国标GB/T 33144-2016相比,测出的冲击韧性具有相似的规律,两种方法极差和标准偏差值相近.激光粒度仪方法可以对小于38 μm直径金刚石微粉进行冲击性能检测,测试结果稳定性较...     

金刚石微粉粒度分析取样定量方法

在金刚石微粉粒度分析检测中,取样量的多少对测试结果的准确性和稳定性有较大的影响。根据透光率等效原理,提出了一种定量取样方法。按照文章提出的方法,操作者能够一次配制成功,可大幅提高制样效率、规范制样程序,提高测试结果的准确性和稳定性。结果表明,利用提出的定量取样方法,使分析结果的稳定性与常规制样方法相比提高30倍以上。     

双检法在金刚石微粉检验中的应用

微粉粒度检测中单独使用一种方法总是存在这样或那样的缺陷。文章通过介绍激光粒度分析和图像分析法在粒度检测中各自存在的优缺点,建议在生产实践中将两种检测方法相结合,取长补短,确保金刚石微粉粒度检测的全面性及准确性。     

金刚石微粉的质量测评

近十年来,我国在金刚石微粉的研发和生产上进展很快,已经步入世界金刚石微粉生产大国的行列,但是与欧美等发达国家同类产品的质量水平相比,还有较大的差距,尤其是在杂质含量,粒度分级,颗粒形貌和适用性方面,差距甚远.文章通过对国内外金刚石微粉样品的大量测试与评判,对其产生质量差异的不同程度及原因进行了深入细致地研究,探讨如何提高金刚石微粉的质量品级,进而赶超世界先进水平的路径.     

金刚石微粉整形技术研究

研究了通过自制生产用滚筒式整形球磨机对金刚石微粉的整形效果。针对不同的原料,采用不同的球料比及球磨时间,且在所有钢球的内部配比也不同的情况下进行反复实验调整,整形后最终获得形状近似等积形、块状的微粉,且分级出的同一规格的微粉整体较均匀,基本上无片状或长条状颗粒。     

不同粒度金刚石微粉对PCD微结构与性能的影响

在烧结温度为1550℃、合成压力为5.7士0.1GPa、烧结时间180s时,采用国产六面顶压机进行了微米级聚晶金刚石的合成试验,研究不同粒度(10μm、5μm、2μm,1μm)的金刚石微粉对合成的PCD微结构与性能的影响.分别采用了SME、XRD和Raman对合成的PCD样品的微结构进行表征,并测试其耐磨性和耐热性.结果表明,PCD试样中均形成了D-D结合,且当金刚石原料粒度为2μm时,样品中存在石墨;随着金刚石原料粒度的减小,Co元素的扩散更加均匀,合成PCD样品的磨耗比越小,耐热温度越低.     

金刚石微粉表面镀覆技术研究进展

金刚石微粉表面镀覆能够提高其热稳定性、增强其对金属的润湿性和改善表面物理性能,对金刚石微粉的性能提高具有重要意义。综述了适用于金刚石微粉表面镀覆技术的化学镀、溶胶凝胶镀及原子层沉积镀等方法,总结了每种方法的原理、优缺点及研究进展,最后对金刚石微粉表面镀覆进行了展望。     

微粉的制造技术

微粉具有特殊的应用功能,目前国内外已在工业上广泛使用。生产工艺多种多样,大部分已工业化。微粉制造技术主要分为化学法和物理法两大类。前者包括沉淀法、蒸发分解法、喷雾干燥法等。后者包括机械粉碎法,熔融体粉碎法、蒸发凝结法等。微粉制造在矿产品综合利用和深加工中具有重要地位。     

应用造粒工艺制造速溶的浓缩粉

采用造粒工艺,开发出一种速溶家用浓缩粉的生产方法.这种洗衣粉粒子具有空心结构,因而具有速溶特性.该工艺要求n-SAA至少占总表面活性剂的30%,以保证具有优良的去污力.这种洗衣粉专供具有低机械力的全自动洗衣机使用,并满足人们洗涤容量大、节水、省时的洗涤要求.     

抛光粉制备工艺的研究

本文针对抛光粉制备工艺的发展历史、制备方法和应用领域进行了综合述评。并对抛光粉制备工艺中彭响因素提出了自己的见解。     

A new elegant technique for polishing CVD diamond films

It is well known that the columnar growth nature of CVD diamond results in a very rough growth surface and the surface roughness steeply increases with film thickness, especially for thick CVD diamond films. In this paper, we report the successful implementation of a new elegant technique for polishing thick polycrystalline CVD diamond films at high polishing rate of up to 10 μm/h. This technique involves polishing the as-grown polycrystalline diamond films with another thick as-grown polycrystalline diamond film, which acts as a polishing abrasive. Two types of diamond films were prepared using microwave plasma CVD and then polished for 2 h using the new polishing technique. A stylus profilometer, scanning electron microscopy and Fourier transform infrared spectroscopy were used to measure the surface roughness, characterize morphology and optical transmission of the samples before and after polishing, respectively. By polishing, thickness of 20–30 μm was removed from the top surface, and the mean surface roughness R_a of the films reduced significantly, e.g. for one film R_a reduced initially from 5.2 to 1.35 μm and the other from 3.2 to 0.55 μm. The principal advantages of this new polishing technique are simplicity, flexibility and time saving. This simple method can serve as ‘rough chipping’ to quickly remove the rough top surface and then combine with conventional polishing methods for precision machining to further reduce the surface roughness to a specific desired degree.     

A super-high speed polishing technique for CVD diamond films

A new set-up for polishing of CVD diamond films on a high speed rotating titanium plate has been developed. The influence of polishing pressure on the surface character, roughness and material removal rate have been studied by using scanning electron microscopy, stylus profilometer, X-ray photoelectron spectroscopy and Raman spectroscopy before and after polishing, respectively. The results showed that the material removal mechanism is mainly the chemical reaction between carbon and titanium and the diffusion of carbon atoms into the polishing plate during the super-high speed polishing. The current method exhibits a high polishing rate in only a few hours. This preliminary result reveals a great potential for commercializing.     

Wear process of single crystal diamond affected by sliding velocity and contact pressure in mechanical polishing

In this work, the influences of sliding velocity and contact pressure on the wear rate of diamond substrate in mechanical polishing are investigated experimentally and theoretically. The experimental observations indicate that the wearing process only consists of the wear-in and stable wear periods. The removal thickness of diamond crystal first increases nonlinearly in the wear-in stage, but then linearly in the subsequent stable wear stage. A diamond carbon amorphization-dependent model is established to calculate the linear variations of removal thickness, which gives a satisfactory prediction accuracy as compared to the experimental data. Although the experiment results demonstrate that the higher sliding velocity or contact pressure will cause a higher wear rate of diamond substrate, the action laws are thoroughly different according to the theoretical prediction. A greater sliding velocity increases the amorphization rate of diamond carbons and the scratching frequency of diamond grits. However, a higher contact pressure produces a larger contact area, which forces more diamond grits to scratch on the surface of diamond substrate.     

Synthesis and polishing characteristics of a novel green GO/diamond hybrid slurry under ultrasonic technology

Ultrasonic polishing (UP), as an efficient and clean precision machining process, is increasingly applied in the hard and brittle material processing. To minimize the surface damage and polishing expenses, this paper aims to prepare novel graphene oxide/diamond hybrid slurries (GDS) by ultrasonication, and to investigate the UP mechanisms for silicon carbide (SiC) ceramics on UP and tribological experiments. Findings showed that GDS exhibited superior polishing performance compared to diamond polishing slurries. Moreover, the promotion effect of GDS was more obvious under UP. The surface roughness was improved by 31.62% after UP using GDS with a graphene oxide (GO) content of 0.1 wt%. On the one hand, the lubrication of GO reduce the wear and coefficient of friction. On the other hand, ultrasonic vibration induces stronger impact kinetic energy of abrasives to remove material and allows for a better uniform distribution of GDS to further enhance the lubrication characteristics of GO nanosheets. The application of GO in UP is a processing technology penetrating the manufacturing industry and even human life, laying the foundation for SiC nano-polishing.     

A parametric relationship for synthesized diamond powder

Diamond powders synthesized in different solvent/catalyst systems at high pressure and high temperature conditions contain crystals that could be separated into groups of distinct size and defect morphology. These groups differ by their mechanical compressive resistance, given by the fracture load, which could be used to classify them for potential industrial applications. In the present work a parametric relationship between the defect morphological aspects, the granulometry and the compressive resistance of diamond powders synthesized in a concave anvil high-pressure device at 4.7 GPa and 1250 °C was established. Results were obtained by measuring the fracture load, using the single grit test of individual crystals, and comparing the average value for crystals with different defect morphology and corresponding grain sizes. The parametric relationship permitted to classify each diamond crystal by its size and defect morphology in association with its compressive resistance. It is therefore suggested that this parametric relationship be used as a new method to evaluate a diamond powder in terms of crystal size, defect morphological aspects and mechanical resistance.