Ni-P-金刚石粉化学复合镀层的性能

本文用扫描电镜对Ni－P－金刚石粉化学复合镀层的表面状态及内部形貌进行了观察，并用图像处理仪定量计算了复合镀层中金刚石粉的体积百分数。结果表明，随镀液中金刚石粉添加量增加，镀层中金刚石粉含量也增加；金刚石粉在镀层中呈均匀分布。同时，测定了复合镀层的力学性能，结果指出，复合镀层中金刚石粉含量增加，硬度、耐磨性提高。     

脉冲高能量密度等离子体沉积氮化钛膜的结合强度

本文用脉冲高能量密度等离子体技术，在室温条件下，成功地在ＧＣｒ１５钢表面沉积了性能良好的氮化钛薄膜。用自动划痕试验仪测量了氮化钛薄膜的结合强度。研究结果表明：表征薄膜结合强度的临界载荷有相当高的值；氮化钛薄膜的临界载荷随脉冲轰击次数、内外电极的电压变化而变化。对沉积膜结合强度的这些变化给予了理论上的解释与讨论。     

Application of High Temperature Corrosion-Resistant Materials and Coatings Under Severe Corrosive Environment in Waste-to-Energy Boilers

Corrosion-resistant materials (CRMs) and coatings are key technologies to increase power generation efficiency and reduce maintenance in waste-to-energy (WTE) plants. Corrosion environment became severe as steam temperatures have increased. The steam condition of more than 400 °C/3.9 MPa became possible in WTE boilers by using highly durable corrosion-resistant coatings, such as thermal spray of Al/80Ni20Cr alloy, HVOF-sprayed NiCrSiB alloy, Alloy 625 weld overlay for waterwall tubes and also superheater tubes. Also, the use of 310S type stainless steels and high Cr-high Mo-Ni base and high Si-Cr-Ni-Fe alloys have progressed because of a better understanding of corrosion mechanisms. Furthermore, high durability coatings using cermet and ceramic materials were applied to high temperature superheaters. This paper describes the major developments and the application of CRMs and coating technologies in the last 30 years in WTE plants, the corrosion mechanisms of alloys, the deterioration mechanisms of spray coating layers, and future subjects for the development of corrosion-resistant materials and coatings.     

纳米金刚石的应用

纳米金刚石不仅具有金刚石所固有优异特性，而且还具有纳米材料所拥有的奇异性能。正是这些综合技术特性，使得它在传统的和新的技术领域中得到应用，并初见成效，本文从超精抛光、润滑、复合镀、磁性录音系统和医疗等方面的应用做了扼要的叙述，指出，纳米金刚石颗粒具有球形和准球形的特点，使得摩擦表面形成滚珠轴承效应，而表现出良好的润滑性，从而避免于摩现象的发生，而对一些主要因接触疲劳或高温磨损而失效的工件，纳米金刚石金属的复合涂层，则具有明显的优越性。     

切削刀具PVD涂层技术的发展及应用

PVD涂层是利用蒸发、辉光放电等物理过程 ,在基材表面沉积出所需要的涂层的技术 ,通常采用的 PVD技术有蒸发镀膜、离子镀膜和溅射镀膜三大类 ,其中离子镀和溅射镀适合于对切削刀具进行超硬材料涂层。本文着重介绍了溅射镀技术及采用该技术生产的几种重要的涂层 ,结合实例介绍了它们的使用性能 ,并对 PVD涂层切削刀具技术的研究进展 ,工业化生产及应用现状进行了综述。     

稀土硅铁对TBCs梯度热障涂层组织与性能影响的研究

通过低压等离子喷涂技术在Ni基合金表面制备了Y2O3－CeO2-TZP/NiCoCrAlY梯度热障涂层，采用光学显微镜、X射线衍射仪、扫描电镜、电子探针等方法研究了稀土硅铁对Y2O3－CeO2-TZP/NiCoCrAlY梯度热障涂层的组织和性能的影响。结果表明，在涂层中加入适量的稀土硅铁，能改善涂层的组织结构，提高其抗热震性能和抗高温氧化性能。     

The Main Degradation Modes of an Aluminide Coating on a Co-Base Superalloy During High-Temperature Oxidation in Air

Degradation of aluminide coatings occurs by two ways, one by coating oxidation, and the other by interdiffusion of Al. In this paper, the structure variation and phase transformation are analyzed for the aluminide coating on a newly developed Co-base superalloy (DZ40M alloy) after oxidation at 900 and 1000°C in air. The results show that degradation of this coating was mainly by oxidation at 900°C, but principally by interdiffusion at 1000°C. The main degradation mode of the coating is primarily dependent on the oxidation temperature and the specific structure of the coating itself.     

Oxidation behavior of TiAl coated with a fine-grain Co-30Cr-4Al film

The oxidation behavior of TiAl coupons coated with a fine-grain Co-30Cr-4Al (mass %) film of about 30-m thickness has been studied at 1100–1400 K in a flow of purified oxygen at atmospheric pressure for up to 500 ks. Three oxidation stages were recognized: initial transient, parabolic, and accelerated stages. However, at 1100 K a parabolic stage continues for more than 800 ks. The activation energy for parabolic oxidation agrees with reported values for the oxidation of alumina-former alloys, although the mass gains during the parabolic stages are relatively small at 1200 and 1300 K. Micropores developed mainly at the scale/coating and coating/substrate interfaces as oxidation proceeded. This is attributable to recrystallization of the coating during oxidation and a Kirkendall effect due to preferential diffusion of Co into the substrate. The accelerated oxidation can be explained in terms of the formation of rutile mounds on the scale.     

Optimization of spraying process and laser treatment of CoNiCrAlY

This article describes the investigation of a new generation of vacuum plasma sprayed CoNiCrAlY coatings on NiCr20Ti in the sprayed as well as the laser-treated condition. The aim of the study was the improvement of MCrAlY coating properties by modifying the microstructure through laser remelting with 5-kW Co₂: lasers. Parameter analysis and optimization was carried out for the vacuum plasma spraying process, as well as for the laser remelting technique. The effect of the laser treatment on microstructure, quality of the coatings, and oxidation as well as hot gas corrosion behavior are reported.     

Resistance of Mo-bearing stainless steels and Mo-bearing stainless-steel coating to naphthenic acid corrosion and erosion-corrosion

Naphthenic acid corrosion (NAC) and erosion-corrosion (NAEC) behavior of Mo-bearing (0-7.0 wt.%) stainless steels have been investigated in laboratory to evaluate the essential role of Mo on their NAC and NAEC resistance. The NAC and NAEC resistance of a high-velocity-oxygen-fuel (HVOF) thermal sprayed Mo-bearing stainless-steel coating was also investigated in both laboratory and an oil refinery. It was found that increasing the Mo content remarkably enhanced the NAC and NAEC resistance of stainless steels. The Mo-rich areas or phases in the steels played an importance role in resisting the NAEC. The HVOF coating showed excellent NAC and NAEC resistance in laboratory tests. The 700-day field test in an oil refinery revealed that the coating can effectively prevent the carbon-steel substrate from erosion-corrosion during long-term exposure in oil-refining environment. The corresponding NAC and NAEC mechanisms of the stainless steels and the beneficial role of Mo were discussed by taking account of inherent susceptibility of metal elements to corrosion, possible effects of Mo on surface films, and Mo-induced change in microstructure and microhardness.