CN200610017366．5外间接加热式金刚石合成块

外间接加热式金刚石合成块,属于金刚石合成技术领域。包括金刚石合成柱,合成柱两端设置有复合导电隔热装置,合成柱及复合导电隔热装置外侧套设有密封传压介质,密封传压介质及复合导电隔热装置与合成柱之间自外向内依次设置有发热元件、传热元件和隔离元件。复合导电隔热装置包括导电金属圆片和一端与其相接且直径较小的金属圆筒,     

一种新型复合传压密封介质的研制

本文提出一种新型复合传压密封介质的研制方法，该介质外围材料为叶蜡石，内套一白云石套管。通过金刚石合成试验得出：合成压力下降2-3MPa；合成电流下降100～200A；合成出的金刚石单产提高5ct左右，粒度相对集中、≥50／60以粗晶粒所占比例达到85％，晶型好。     

KH-151硅烷改性纳米ZrO2对铝合金表面环氧树脂涂层防护性能的影响

在6061铝合金表面制备了硅烷改性纳米ZrO₂环氧树脂涂层,采用电化学测试和腐蚀试验,研究了纳米ZrO₂添加量对硅烷改性纳米ZrO₂环氧树脂涂层防护性能的影响,并对比了不同转化处理工艺下涂层的物理性能和防护性能。结果表明：当纳米ZrO₂添加量为100 mg/L时,硅烷改性纳米ZrO₂环氧树脂涂层试样的极化电阻为2 719Ω·cm²、自腐蚀电流密度为2.528×10^-6 A·cm^-2;在经不同转化处理工艺处理的涂层中,硅烷改性纳米ZrO₂环氧树脂涂层的平均厚度为55μm,涂层剥离面积比例为5%,附着力达到1级,极化电阻最大,自腐蚀电流密度最小,涂层防护性能最佳。     

新型复合传压介质的研究

本文详细的分析了在金刚石合成中叶蜡石、白云石、氯化钠作为传压介质的优缺点，并通过大量的实验，证实了用多种复合传压介质代替单一的叶蜡石做传压介质在金刚石合成中得到了理想的效果，不仅降低了锤耗而且提高了金刚石质量。     

粉压叶蜡石性质对金刚石的合成影响

叙述了粉压叶蜡石在金刚石合成中的作用与影响，讨论了粉压叶蜡石性质对金刚石合成技术及其效果的影响，指出了正确选择使用粉压叶蜡石传压密封介质高压容器的重要性和提高其质量的途径与方法。     

复合传压介质应用的初步探讨

本介绍了复合块合成人造金刚石的试验情况，从初步试验结果中发现，复合传压介质，对降低预锤消耗，提高生产效率，减少“白头”，黑晶等，均起到一定的作用。     

国产无压机分球式超高压装置用硬质合金顶锤的研究

介绍无压机分球式超高压装置（BARS——俄文的首字母БАРС=Беспрессовая Аппаратура высокого давления "Разрезная Сфера"）合成宝石级金刚石的基本原理,分析BARS装置用硬质合金顶锤的功能特性,论述国产BARS装置用硬质合金顶锤成功工业化应用的研究过程。研究表明:选用WC-Co细颗粒复合粉,并采用搅拌球磨、冷等静压压制和低压烧结等综合技术,能提高细晶粒材料的组织结构均匀性、抗压强度及弹性模量,满足顶锤高强度、高刚性的使用需求。同时,采用在磨削中互为基准的工艺方案,控制产品上下同轴线是自定位顶锤合理的加工方案;选用粒度号M22/36的砂轮做精磨砂轮,合理的进刀量是保证加工精度的关键。      

超音速等离子喷涂ZrO2-MoSi2涂层的组织及耐磨性能

为了研制一种新型的连铸结晶器涂层材料,采用超音速等离子喷涂技术在CrZrCu基体表面制备ZrO₂-MoSi₂/CoNiCrAlY复合涂层。通过SEM、XRD和EDS等分析测试手段对涂层的微观组织、形貌及物相组成进行表征,并利用摩擦磨损试验机对ZrO₂-MoSi₂涂层与NiCo电镀层的耐磨性能进行比较。结果表明：超音速等离子喷涂可形成熔化或半熔化状态的致密层状结构组织,涂层主要由MoSi₂、ZrO₂、Mo₅Si₃和少量的单质Mo相组成,相对于NiCo电镀层,ZrO₂-MoSi₂涂层的摩擦磨损性能提高了近5倍。     

传压介质在人造金刚石合成中的性能研究

研究了六种不同的传压介质：灰白叶蜡石块、带白云石衬管的灰白叶蜡石块、带红叶蜡石衬管的灰白叶蜡石块、灰白／青灰叶蜡石复合块、中粒度灰白叶蜡石复合块、细粒度灰白叶蜡石复合块；分析了各种传压介质原料的成分，采用常用的温度一压力曲线，进行了合成金刚石的实验，对合成金刚石结果进行了对比分析，结果表明：不同传压介质合成金刚石的品级、粒度不同，其中红叶蜡石内衬复合块以及白云石内衬复合块合成的金刚石晶型、颜色等各项指标最好，这是因为，灰白叶蜡石的传压效果好，红叶蜡石以及白云石内衬的保温性好，综合了两种材料的优点，改善了反应腔中的压力场与温度场分布的均匀性。叶蜡石及内衬材料经过预处理，去除了一部分有害物质使金刚石的生长环境得到了净化。     

对金刚石合成棒中白色物的研究

对金刚石合成棒中白色物进行了研究。经分析其主要成分是2MnO·SiO_2复合氧化物。实验证明,在合成金刚石的条件下如果传压介质——叶蜡石存在吸附水,造成对传压介质性能的玻坏,而且当吸附水浸入反应腔,引起溶媒演变,金刚石晶体生长受污染,影响金刚石的质量和产量。讨论了2MnO·SiO_2的形成机制和演变过程。最后就消除2MnO·SiO_2,合理选材提出了初步意见。     

高压合成工艺中固体密封传压介质研制探讨

分析了我国高压合成工艺中密封传压介质原料应具有的性能——传压性、密封性、黏滞性、流变性、化学惰性、绝缘性及热传导性。从原料组成与结构两方面探讨了密封传压介质的研制方向,指出层状硅酸盐矿物是目前密封传压介质原料的选择原料。同时,密封传压介质的结构对其使用性能也有重要影响,应在扩大合成腔体、方腔体、非立方体等非传统结构上进行深入研究。最后,提出密封传压介质粉压成型、焙烧制作工艺过程及其注意的问题。     

Formation of high hardness zirconia coatings by gas tunnel type plasma spraying

The high hardness zirconia (ZrO₂) coatings could be obtained at an atmospheric pressure by using a gas tunnel type plasma spraying. The characteristics of these high hardness ZrO₂ coatings were investigated. The Vickers hardness of the ZrO₂ coating at a short spraying distance was very high; a high hardness of more than H_v=1200 was achieved at the surface side of the coating. The microstructure of the obtained high hardness ZrO₂ coating was also investigated by the microscopic method. And the characteristics of the high hardness ZrO₂ coating was discussed in comparison with that of the coating formed by the conventional type plasma spraying. It was clarified that the ZrO₂ coating of the gas tunnel type was not only much harder but also less porous than that of the conventional type.     

Stability evaluation of fluorite structure phases in ZrO2-MO2 (M=Th, U, Pu, Ce) systems by thermodynamic modelling

Thermodynamic modelling was demonstrated for ZrO₂-ThO₂ system based on the data for the ZrO₂-UO₂ and ZrO₂-CeO₂ systems in the literature. The calculated phase diagram for the ZrO₂-ThO₂ system showed a good agreement with the experimental data in the literature. Using the data obtained, together with the data for ZrO₂-UO₂, ZrO₂-PuO₂ and ZrO₂-CeO₂ systems, the stability of the fluorite structure phases in the ZrO₂-MO₂ (M=Th, U, Pu, Ce) systems was also studied with respect to the partial molar quantities. The effect of the ZrO₂ on the enthalpy in the MO₂ rich region increased as the cation size of the matrices decreased. The solubility limits of the ZrO₂ in the fluorite structure phase in this region also increased as the cation size of the matrix decreased. The effect of MO₂ on the partial molar Gibbs energy in the ZrO₂ rich region increased as the cation size of the MO₂ increased. It implies that the dissolution of the larger cation stabilises the fluorite structure of the ZrO₂ more.     

Stress analysis of high temperature ZrO2 insulation coatings on Ag using finite element method

The aim of this study is to investigate residual stresses occurred during cooling procedure of ZrO₂ insulation coating on Ag substrate for magnet technologies. ZrO₂ coatings were produced on Ag tape substrate by using a reel-to-reel sol–gel technique. SEM inspection showed that ZrO₂ coatings had mosaic structures. ANSYS finite element software was used to calculate the temperature and stress distribution of the ZrO₂/Ag structure. The effect of coating thickness on residual stresses was also examined. The results obtained showed that thermal stresses in ZrO₂ coating and Ag substrate were considerably affected by the cooling time and coating thickness. It is concluded the thermal stresses increase with increase of film thickness.     

Powder processing and densification behaviour of alumina–high zirconia nanocomposites using chloride precursors

Al₂O₃–ZrO₂ composites having nominal equal volume fraction of Al₂O₃ and ZrO₂ were prepared from gel-precipitated powder, precipitated powder and washed precipitated powder. These different processing routes affected the crystallization temperature of the amorphous powder as well as the phase evolution of Al₂O₃ and ZrO₂ during calcination. The agglomerate size was largest for gel-precipitated powder (30 μm) and it was smallest for washed precipitated powder (19 μm). While gel-precipitated powder produce hard agglomerated powder (P_j = 110 MPa), washed precipitated powder produce soft agglomerates with low agglomeration strength (P_j = 70 MPa). Thus, washed precipitated powder could sinter to a high density at lower sintering temperature. The bending strength exhibits a semi logarithmic relationship with porosity. The hardness shows an increasing trend with sintering temperature.     

Thermal modeling of various thermal barrier coatings in a high heat flux rocket engine

One- and two-dimensional thermal models were developed to predict the thermal response of tubes with and without thermal barrier coatings (TBCs) tested for short durations in a H₂/O₂ rocket engine. Temperatures were predicted using median thermophysical property data for traditional air plasma sprayed ZrO₂–Y₂O₃ TBCs, as well as air plasma sprayed and low pressure plasma sprayed ZrO₂–Y₂O₃/NiCrAlY cermet coatings. Good agreement was observed between predicted and measured metal temperatures. It was also shown that the variation in the reported values of the thermal conductivity of plasma sprayed ZrO₂–Y₂O₃ coatings can result in temperature differences of up to 180°C at the ceramic/metal interface. In contrast, accounting for the presence of the bond coat or radiation from the ceramic layer had only a small effect on substrate temperatures (<20°C). The thermal models were also used to show that for the short duration test conditions of this study, a 100 μm thick ZrO₂–Y₂O₃ coating would provide a metal temperature benefit of approximately 300°C over an uncoated tube while a 200 μm thick coating would provide a benefit greater than 500°C. The difference in the thermal response between tubes and rods was also predicted and used to explain the previously-observed increased life of TBCs on rods over that on tubes.     

Effect of addition of Cu into ZrOx film on its properties

The article reports on the effect of addition of Cu into the ZrO₂ film on its structure, physical and mechanical properties. The ZrO₂ and Zr–Cu–O films were reactively sputtered using a dc unbalanced magnetron from Zr (99.9) and ZrCu (90/10 at.%) targets in Ar + O₂ mixture at the substrate temperature T_s = 300, 400 and 550 °C and total sputtering gas pressure p_T = 1 Pa on steel, Si(100) and glass substrates. The structure of films was characterized by an X-ray diffraction (XRD) and mechanical properties, i.e. microhardness H, effective Young's modulus E* = E / (1 − ν²) and elastic recovery W_e, were measured using a microhardness tester; E and ν are the Young's modulus and the Poisson ratio, respectively. The film brittleness was characterized by the formation of cracks during the diamond indenter impression into it. 5 μm thick ZrO₂ films prepared in the oxide mode of sputtering are crystalline (m-ZrO₂) and exhibit relatively (i) high hardness H≈16 GPa and (ii) low ratio H³ / E*²≈0.11 GPa. The Zr–Cu–O films with low (≤ 2 at.%) Cu content exhibit (i) crystalline structure, (ii) higher H, (iii) lower (− 1.5 GPa) macrostress σ and (iv) higher ratio H³ / E*²≈0.14 GPa. On the contrary, the Zr–Cu–O films with high (24 to 44 at.%) Cu content exhibit (i) X-ray amorphous structure, (ii) lower H≈11 GPa and lower ratio H³ / E*²≈0.075 GPa. A special attention was devoted to the investigation of cracking of Zr–Cu–O films under high (0.5 and 1 N) loads of the diamond indenter. The relations between the film cracking and properties of the film and the substrate were used to assess the toughness of the Zr–Cu–O film. It was found that the film toughness increase with increasing H³ / E*² ratio. It was shown that the addition of Cu to ZrO₂ film can improve its toughness.     

ZrO2纳米颗粒对PEO涂层微观结构及热物理性能的影响

目的 提高PEO涂层的热物理性能.方法 以活塞主流材料——高硅铝合金(ZL109)为基体,在硅酸盐系电解液中,添加不同浓度的ZrO2纳米颗粒,制备一系列ZrO2/Al2O3复合PEO涂层,并通过涡流测厚仪、扫描电子显微镜(SEM)、能谱仪(EDS)及X射线衍射仪(XRD)分析ZrO2纳米颗粒对涂层生长、微观形貌、元素组...     

Crystallisation of oxygen-stabilised amorphous phase in a Zr50Cu50 alloy

The crystallisation of the oxygen-stabilised amorphous phase in a Zr₅₀Cu₅₀ alloy has been investigated by means of neutron diffraction and electron microscopy. The crystallisation microstructure consists of ZrO₂, Zr₂Cu and Zr₇Cu₁₀. A two-stage crystallisation mechanism is suggested: (i) primary crystallisation of Zr₂Cu and (ii) formation of nanocrystals ZrO₂ and Zr₇Cu₁₀. In (i), it is proposed, Zr₂Cu crystallises from the oxygen-stabilised amorphous phase, leaving an oxygen- and copper-enriched matrix ; Zr₂Cu rapidly grows and eventually attains a grain size of about 100 nm. In (ii), it is suggested, the residual amorphous matrix crystallises into nanocrystals ZrO₂ and Zr₇Cu₁₀ due to the sluggish growth of ZrO₂ and to the already formed ZrO₂ which acts as a growth barrier to Zr₇Cu₁₀. In this case there is no particular orientation relationship between Zr₂Cu and Zr₇Cu₁₀.