金刚石表面沉积钛金属膜的研究

金刚石表面化学镀Ni—W—P后 ,再化学复合镀Ni—Ti(粉 )—Re(稀土 ) ,能明显提高金刚石表面强碳化物元素的沉积 ,有利于生成WC—TiC薄膜 ,提高金刚石同胎体合金的联结强度 ,达到提高金刚石工具的性能的目的。     

提高胎体金属与金刚石粘结性能的研究

从研究粘结金属在液态时与骨架材料和石墨(代替金刚石)的相互作用规律人手,对加入有强碳化物形成元素的几种铜基系列粘结材料做一系列实验,从中选择对金刚石润湿性好,附着功大的一种制成预合金化粉末粘结剂,同时采用金刚石表面离子化和改进烧结工艺,提高和改善胎体性能.本文以大量的实验资料对提高胎体金属与金刚石的粘结性能作一些讨论.     

金刚石均布钻头的研究与试验

为解决钻头在使用过程中因金刚石分布不均匀而产生的金刚石过早脱落,胎体拉沟、掉块等问题,研制出金刚石均布工艺,用该工艺生产的钻头,胎体中金刚石可达到等间距排列,取到了很好的使用效果.     

高胎体金刚石钻头设计制造中的几个关键技术

为满足深部钻探需求,市场上出现了多种高胎体金刚石钻头。在野外钻进中,与普通金刚石钻头相比,高胎体金刚石钻头的使用寿命虽有提高,但并没有取得预期的理想效果。通过分析国内外几种高胎体金刚石钻头的优缺点,找出了影响高胎体钻头寿命的关键技术,并对这几点关键技术作了进一步的分析与研究。     

孕镶金刚石钻头的设计和使用

本文通过介绍国外硬、软胎体金刚石钻头的使用情况，提出了设计与使用孕镶金刚石钻头过程中一些值得注意的问题。     

热压高磷铁基胎体性能及其金刚石钻头研究

针对在硬而致密岩石中钻进时效低和钻头使用寿命短以及传统金刚石钻头胎体材料价格高等众多难题,采用混料回归试验设计方法,进行了替代碳化钨基金刚石钻头胎体材料的新型铁基胎体配方的试验研究;分析了热压钻头的金刚石出刃与岩石研磨性等岩性之间的内在联系,认为钻头的胎体成分及其性能是关键。因此,从热压金刚石钻头的胎体成分与性能研究入手,经过反复的试验研究与优化组合,研究出热压高磷铁基孕镶金刚石钻头的胎体材料,并试制出金刚石钻头。在室内对可钻性Ⅸ级岩石进行钻进的试验表明：钻进时效平均达到1．91m,钻头平均工作寿命达到60．26m。试验结果表明,高磷铁基眙体是一种性能良好的金刚石钻头胎体材料,且该类型胎体的热压金刚石钻头是一种成本明显降低、具有广谱性能的金刚石钻头。     

金刚石表面镀覆二氧化钛的研究

本文利用四氯化钛和尿素的均一沉淀法,以及四氯化钛,正辛醇和饱和碳酸铵溶液的相转移法,成功地在金刚石表面上镀覆了二氧化钛薄膜,并且讨论了金刚石镀层薄膜的生成机制及影响镀膜层的工艺因素。通过热力学分析认为,镀有二氧经钛薄的金刚石经高温热处理后金刚石表面有碳化物ＴｉＣ生成。     

基于打滑地层的孕镶金刚石钻头设计

为了提高金刚石钻头在坚硬致密、弱研磨性地层的钻进效率, 将弱化胎体耐磨损性能理论与切削齿非光滑设计相结合, 制作钻头进行现场试验并对胎体进行扫描电镜分析.研究结果表明:在胎体中添加适当浓度的胎体弱化颗粒, 有利于提高钻头的钻速; 经胎体耐磨性弱化处理的钻头在钻进过程中, 弱化颗粒易于从胎体表面脱落, 使其表面形成微观非光滑形态, 提高了钻头唇面与岩石的单位面积压力, 增加了孔底岩粉的研磨能力, 促进了胎体中新颗粒金刚石的出刃; 弱化颗粒浓度存在一个较优的设计范围, 过高或过低都不利于提高钻头的钻进效率和使用寿命.      

电镀镍锰胎体金刚石钻头的应用

对电镀镍锰胎体金刚石钻头和镍钴胎体钻头的使用情况进行了对比。实践证明,镍锰胎体钻头特别适用于钻进坚硬破碎、强研磨性地层和软硬交替的地层。     

金刚石刀具胎体配方中以Fe代Co存在的问题分析

本文从胎体金刚石的侵蚀性,胎体对金刚石的包镶力,胎体的耐磨性等三个方面对比分析了以Ｆｅ代Ｃｏ存在的问题,并指出以Ｆｅ代Ｃｏ的关键在应用于镀膜金刚石,即以金刚石表面的碳化膜隔绝铁族元素对金刚石的侵蚀作用,并以碳化物膜作为过渡层实现金刚石与胎体的冶金结构,而胎体的耐磨性则可从优化胎体配方得到解决。     

提高金刚石粘结强度的技术及其应用

真空沉积渗覆法使金刚石表面形成金属碳化物过渡层和化学镀法使金刚石表面生成有良好湿润性的低熔点金刚石过镀层,改善粘结材料对金刚石的粘结状态,提高了粘结强度.通过采用相应的粘结材料和烧结工艺,将金属化金刚石成功地应用于石材切割锯片,取得了提高锯片效率30～100%,寿命延长20%以上的效果.     

Comparison of enigmatic diamonds from the Tolbachik arc volcano (Kamchatka) and Tibetan ophiolites: Assessing the role of contamination by synthetic materials

The enigmatic appearance of cuboctahedral diamonds in ophiolitic and arc volcanic rocks with morphology and infrared characteristics similar to synthetic diamonds that were grown from metal solvent requires a critical reappraisal. We have studied 15 diamond crystals and fragments from Tolbachik volcano lava flows, using Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), synchrotron X-ray fluorescence (SRXRF) and laser ablation inductively coupled plasma mass-spectrometry (LA-ICP-MS). FTIR spectra of Tolbachik diamonds correspond to typical type Ib patterns of synthetic diamonds. In TEM films prepared using focused ion beam technique, we find Mn-Ni and Mn-Si inclusions in Tolbachik diamonds. SRXRF spectra indicate the presence of Fe-Ni and Fe-Ni-Mn inclusions with Cr, Ti, Cu, and Zn impurities. LA-ICP-MS data show variable but significantly elevated concentrations of Mn, Fe, Ni, and Cu reaching up to 70 ppm. These transition metal concentration levels are comparable with those determined by LA-ICP-MS for similar diamonds from Tibetan ophiolites. Mn-Ni (+Fe) solvent was widely used to produce industrial synthetic diamonds in the former USSR and Russia with very similar proportions of these metals. Hence, it appears highly probable that the cuboctahedral diamonds recovered from Kamchatka arc volcanic rocks represent contamination and are likely derived from drilling tools or other hard instruments. Kinetic data on diamond dissolution in basaltic magma or in fluid phase demonstrate that diamond does not form under the pressures and temperature conditions prevalent within the magmatic system beneath the modern-day Klyuchevskoy group of arc volcanoes. We also considered reference data for inclusions in ophiolitic diamonds and compared them with the composition of solvent used in industrial diamond synthesis in China. The similar inclusion chemistry close to Ni₇₀Mn₂₅Co₅ for ophiolitic and synthetic Chinese diamonds scrutinized here suggests that most diamonds recovered from Tibetan and other ophiolites are not natural but instead have a synthetic origin. In order to mitigate further dubious reports of diamonds from unconventional tectonic settings and source rocks, we propose a set of discrimination criteria to better distinguish natural cuboctahedral diamonds from those produced synthetically in industrial environments and found as contaminants in mantle- and crust-derived rocks.     

Metal films on the surfaces and within diamond crystals from Arkhangelskaya and Yakutian diamond provinces

Representative samples of diamonds from five kimberlite pipes (Lomonosovskaya, Archangel’sk, Snegurochka, XXIII Congress of the Communist Party of the Soviet Union (CPSU), and Internationalnaya) of the Arkhangelskaya and Yakutian diamond provinces in Russia have been studied. Thirty-three varieties of metal films have been identified as syngenetic associated minerals. The films consist of 15 chemical elements that occur in the form of native metals and their natural alloys. Remnants of metal films were detected within diamond crystals. The metal films coating diamonds are a worldwide phenomenon. To date, these films have been described from Europe, Asia, South America, and Africa. Native metals, their alloys, and intermetallides are actual companion minerals of diamond.     

Diamonds in the Attawapiskat area of the Superior craton (Canada): evidence for a major diamond-forming event younger than 1.1 Ga

Here, we compare nitrogen aggregation characteristics and carbon isotopic compositions in diamonds from Mesoproterozoic (T1) and Jurassic (U2) kimberlites in the Attawapiskat area—the first diamond-producing area on the Superior craton. The T1 kimberlite sampled diamonds from the lithospheric mantle at 1.1 Ga, at the same time as the major Midcontinent Rift event. These diamonds have a narrow range in δ¹³C (mode of ?3.4 ‰), with compositions that overlap other diamond localities on the Superior craton. Some diamond destruction must have occurred during the Mesoproterozoic in response to the thermal impact of the Midcontinent Rift—the associated elevated geotherm caused a narrow diamond window (<30 km) close to the base of the lithosphere, compared to a wide diamond window of ~85 km following thermal relaxation (sampled by Jurassic kimberlites, such as U2). T1 diamonds have highly aggregated nitrogen, possibly due to the thermal effect of the rift. Diamond-favourable conditions were re-established in the lithospheric mantle after the thermal impact of the Midcontinent Rift dissipated. The poorly aggregated nature of nitrogen in U2 diamonds—compared to highly aggregated nitrogen in diamonds from T1—indicates that renewed diamond formation must have occurred only after the thermal impact of the Midcontinent Rift at 1.1 Ga had subsided and that these newly formed diamonds were subsequently sampled by Jurassic kimberlites. The overall δ¹³C distribution for U2 diamonds is distinct to T1 and other Superior diamonds, further suggesting that U2 diamonds are not related to the older pre-rift diamonds.     

Inclusions in diamonds from the K14 and K10 kimberlites, Buffalo Hills, Alberta, Canada: diamond growth in a plume?

Analyses of mineral inclusions, carbon isotopes, nitrogen contents and nitrogen aggregation states in 29 diamonds from two Buffalo Hills kimberlites in northern Alberta, Canada were conducted. From 25 inclusion bearing diamonds, the following paragenetic abundances were found: peridotitic (48%), eclogitic (32%), eclogitic/websteritic (8%), websteritic (4%), ultradeep? (4%) and unknown (4%). Diamonds containing mineral inclusions of ferropericlase, and mixed eclogitic-asthenospheric-websteritic and eclogitic-websteritic mineral associations suggests the possibility of diamond growth over a range of depths and in a variety of mantle environments (lithosphere, asthenosphere and possibly lower mantle).

Eclogitic diamonds have a broad range of C-isotopic composition (δ¹³C=−21‰ to −5‰). Peridotitic, websteritic and ultradeep diamonds have typical mantle C-isotope values (δ¹³C=−4.9‰ av.), except for two ¹³C-depleted peridotitic (δ¹³C=−11.8‰, −14.6‰) and one ¹³C-depleted websteritic diamond (δ¹³C=−11.9‰). Infrared spectra from 29 diamonds identified two diamond groups: 75% are nitrogen-free (Type II) or have fully aggregated nitrogen defects (Type IaB) with platelet degradation and low to moderate nitrogen contents (av. 330 ppm-N); 25% have lower nitrogen aggregation states and higher nitrogen contents (30% IaB; <1600 ppm-N).

The combined evidence suggests two generations of diamond growth. Type II and Type IaB diamonds with ultradeep, peridotitic, eclogitic and websteritic inclusions crystallised from eclogitic and peridotitic rocks while moving in a dynamic environment from the asthenosphere and possibly the lower mantle to the base of the lithosphere. Mechanisms for diamond movement through the mantle could be by mantle convection, or an ascending plume. The interaction of partial melts with eclogitic and peridotitic lithologies may have produced the intermediate websteritic inclusion compositions, and can explain diamonds of mixed parageneses, and the overlap in C-isotope values between parageneses. Strong deformation and extremely high nitrogen aggregation states in some diamonds may indicate high mantle storage temperatures and strain in the diamond growth environment. A second diamond group, with Type IaA–IaB nitrogen aggregation and peridotitic inclusions, crystallised at the base of the cratonic lithosphere. All diamonds were subsequently sampled by kimberlites and transported to the Earth's surface.     

Morphological Features of Diamond Crystals Dissolved in Fe<Subscript>0.7</Subscript>S<Subscript>0.3</Subscript> Melt at 4 GPa and 1400°C

An experimental study of the dissolution of natural and synthetic diamonds in a sulfur-bearing iron melt (Fe_0.7S_0.3) with high P–T parameters (4 GPa, 1400°С) was performed. The results demonstrated that under these conditions, octahedral crystals with flat faces and rounded tetrahexahedral diamond crystals are transformed into rounded octahedroids, which have morphological characteristics similar to those of natural diamonds from kimberlite. It was suggested that, taking into account the complex history of individual natural diamond crystals, including the dissolution stages, sulfur-bearing metal melts up to sulfide melts were not only diamond-forming media during the early evolution of the Earth, but also natural solvents of diamond in the mantle environment before the formation of kimberlitic melts.     

Nano-and micron-sized diamond genesis in nature: An overview

There are four main types of natural diamonds and related formation processes. The first type comprises the interstellar nanodiamond particles. The second group includes crustal nano-and micron-scale diamonds associated with coals, sediments and metamorphic rocks. The third one includes nanodiamonds and microndiamonds associated with secondary alteration and replacing of mafic and ultramafic rocks.The fourth one includes macro-, micron-and nano-sized mantle diamonds which are associated with kimberlites, mantle peridotites and eclogites. Each diamond type has its specific characteristics. Nanosized diamond particles of lowest nanometers in size crystallize from abiotic organic matter at lower pressures and temperatures in space during the stages of protoplanetary disk formation. Nano-sized diamonds are formed from organic matter at P-T exceeding conditions of catagenesis stage of lithogenesis. Micron-sized diamonds are formed from fluids at P-T exceeding supercritical water stability.Macrosized diamonds are formed from metal-carbon and silicate-carbonate melts and fluids at P-T exceeding 1150℃ and 4.5 GPa. Nitrogen and hydrocarbons play an important role in diamond formation.Their role in the formation processes increases from macro-sized to nano-sized diamond particles.Introduction of nitrogen atoms into the diamond structure leads to the stabilization of micron-and nanosized diamonds in the field of graphite stability.     

金刚石分类、组成特征以及我国金刚石研究展望

金刚石由于其独特的物理化学性质,在经济生产与科学研究中均具有重要价值.金刚石形成于地球大于150 km的深度范围内,是人类可以获得的来自地球深部地幔乃至核幔边界的最直接的样品,因此可以为研究地球深部物质组成和物理化学条件提供重要的素材.金刚石由碳元素组成,还含有微量的杂质元素（如氮、硼、氢、氧等）,其中氮和硼元素对于划分金刚石的晶体结构类型发挥着重要的作用.根据金刚石的产出类型,金刚石可以划分为幔源型、超高压变质型、陨石相关型以及蛇绿岩型金刚石.全球约百分之一的幔源型金刚石含有包裹体,对这些包裹体的研究显示,金刚石主要来源于地球150~200 km深度的岩石圈地幔.这些含有包裹体的金刚石中,仅有1%的金刚石来自于地球深部的软流圈、地幔过渡带、下地幔、甚至核幔边界.我国的金刚石产出类型多样,但是,目前仅山东蒙阴、辽宁复县的金伯利岩矿床以及湖南沅水的砂矿具有经济价值.蛇绿岩型金刚石是近年来金刚石研究领域取得的重要进展,该类型金刚石分布在全球多个造山带不同时代、不同构造属性的蛇绿岩地幔橄榄岩和铬铁矿中,被认为是一种新的金刚石的产出类型.相对于其他国家和地区的金刚石的研究,我国的金刚石领域的研究程度相对较低,缺乏对金刚石结构、化学组成以及包裹体组成的系统研究,制约了对我国金刚石成因的认识,限制了我国的金刚石的找矿工作.因此,亟需结合先进的分析手段对我国的金刚石及其围岩做进一步的研究,以期揭示金刚石的形成过程,为金刚石的找矿提供理论基础.      

Episodic diamond genesis at Jwaneng, Botswana, and implications for Kaapvaal craton evolution

Major element and Re–Os isotope analysis of single sulfide inclusions in diamonds from the 240 Ma Jwaneng kimberlite has revealed the presence of at least two generations of eclogitic diamonds at this locality, one Proterozoic (ca. 1.5 Ga) and the other late Archean (ca. 2.9 Ga). The former generation is considered to be the same as that of eclogitic garnet and clinopyroxene inclusion bearing diamonds from Jwaneng with a Sm–Nd isochron age of 1.54 Ga. The latter is coeval with the 2.89 Ga subduction-related generation of eclogitic sulfide inclusion bearing diamonds from Kimberley formed during amalgamation of the western and eastern Kaapvaal craton near the Colesberg magnetic lineament.

The Kimberley, Jwaneng, and Premier kimberlites are key localities for characterizing the relationship between episodic diamond genesis and Kaapvaal craton evolution. Kimberley has 3.2 Ga harzburgitic diamonds associated with creation of the western Kaapvaal cratonic nucleus, and 2.9 Ga eclogitic diamonds resulting from its accretion to the eastern Kaapvaal. Jwaneng has two main eclogitic diamond generations (2.9 and 1.5 Ga) reflecting both stabilization and subsequent modification of the craton. Premier has 1.9 Ga lherzolitic diamonds that postdate Bushveld–Molopo magmatism (but whose precursors have Archean Sm–Nd model ages), as well as 1.2 Ga eclogitic diamonds. Thus, Jwaneng provides the overlap between the dominantly Archean vs. Proterozoic diamond formation evident in the Kimberley and Premier diamond suites, respectively. In addition, the 1.5 Ga Jwaneng eclogitic diamond generation is represented by both sulfide and silicate inclusions, allowing for characterization of secular trends in diamond type and composition. Results for Jwaneng and Kimberley eclogitic sulfides indicate that Ni- and Os-rich end members are more common in Archean diamonds compared to Proterozoic diamonds. Similarly, published data for Kimberley and Premier peridotitic silicates show that Ca-rich (lherzolitic) end members are more likely to be found in Proterozoic diamonds than Archean diamonds. Thus, the available diamond distribution, composition, and age data support a multistage process to create, stabilize, and modify Archean craton keels on a billion-year time scale and global basis.     

博茨瓦纳奥拉帕金刚石矿床成矿地质特征

博茨瓦纳是世界上金刚石资源最为丰富的国家之一。奥拉帕金刚石矿床是该国最大的金刚石矿,矿床的金伯利岩为Ⅰ型,其中的包体可以分为2种:橄榄岩型和榴辉岩型;金刚石可以分为3类:橄榄岩型、榴辉岩型及两者的过渡类型-二辉岩型。其中,橄榄岩型和部分榴辉岩型金刚石来自于地幔结晶堆晶体,而榴辉岩型则与板块俯冲的构造-热事件有关。金伯利岩的形成时代主要为白垩纪,而金刚石则主要形成于元古宙和太古宙,金伯利岩和金刚石为不同时期的产物,金刚石为金伯利岩侵位期间捕获的上地幔物理破碎产物。其中年龄为900~1000Ma的金刚石为板块构造-热事件的产物,并对早期金刚石进行了改造破坏。