(Ti,Al)N薄膜的升温出气特性研究

介绍了采用多弧离子镀方法在不锈钢表面镀覆(Ti,Al)N薄膜,并对膜的结构、表面成分和形貌进行了简单分析,用热出气方法研究其出气特性,并与不锈钢的热出气性能进行比较,发现在不锈钢表面镀覆一层(Ti,Al)N膜可以有效地阻挡不锈钢体内氢扩散和碳偏析,因此(Ti,Al)N是比较理想的真空材料。     

Titanium nitride film as a protective coating for a vacuum deposition chamber

A hard and anti-corrosive titanium nitride coating is proposed for use as a permanent coating layer on the inside walls of vacuum chambers and tooling that are exposed to repeated depositions of soft metals. Excellent characteristics for the removal of deposited aluminum or copper by either chemical cleaning or glass bead blasting are demonstrated. The completion of removal can easily be monitored by the obvious gold color of the coating layer.The outgassing rate at room temperature is considerably lower than that of bare stainless steel plate. Characterization of the titanium nitride layer is made by X-ray diffraction, Auger electron spectroscopy, electron spectroscopy for chemical analysis, and secondary ion mass spectrometry.     

Titannitrid als gasabgabereduzierende Schicht auf Edelstahl

TiN films were deposited on stainless steel samples using a new coating procedure, the so-called modified pulse arc process. The influence of titanium nitride films on the outgassing rate was studied and the obtained results were discussed. Measurements of the outgassing rate carried out with untreated stainless steel samples and with stainless steel samples coated with titanium nitride by DC arc process are compared with the results obtained from the samples coated with the modified pulse arc process in order to get information about the influence of the coating procedure on the outgassing rate.     

Deposition of biomimetic biocompatible oxides on metallic glass surface by electro-discharge coating process

Bulk metallic glass demonstrates superior mechanical properties and excellent bio-mechanical stability compared to routinely used biomaterials like titanium, cobalt-chromium, stainless steel, et cetera. However, the metallic glass surface do not easily adhere to the leaving tissues due to native bio-inert oxide layer, which have poor wear resistance and low hardness. In this current study an innovative method for surface coating of bulk metallic glass by mixing hydroxyapatite powder during electro-discharge machining has been employed. A biomimetic nano-porous bio-ceramic layer of oxides and carbides was deposited on metallic glass surface. The modified surface integrity and composition were investigated by scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction characterization techniques. The characterization results confirmed the formation of a natural bone-like nano-porous surface topography on the metallic glass surface using a novel hydroxyapatite-mixed electro-discharge coating process. In addition, a favourable surface chemistry in the form of bioceramic carbides (zirconium carbide, titanium carbide) and zirconium oxide layers, was achieved.     

不锈钢材料在真空炉高温除气后的出气性能比较

根据兰州重离子加速器冷却储存环真空系统(HIRFL-CSR)材料处理工艺要求,需要对所有不锈钢元件进行真空炉高温除气处理以降低材料出气率.本文通过一组实验测试数据,介绍了采用除气处理工艺和未经除气处理的不锈钢材料出气情况对比,证明采用真空炉除气处理工艺可以使材料内部的H2、CO、CO2等组分大幅度减少,从而获得较低的材料出气率.     

Materials and processing of vacuum components for the high-intensity proton beam accelerator, J-PARC

The Japan Proton Accelerator Research Complex (J-PARC) project of the proton beam accelerator, involving a 400-MeV linac, a 3-GeV rapid-cycling synchrotron and a 50-GeV synchrotron, started in 2002. Materials used as vacuum components, such as electroformed copper, titanium, stainless steel and alumina ceramics, were examined from the point of view outgassing and electrical breakdown. The mechanical characteristics of a hydro-formed titanium bellows and a quick-disconnect flange system were also investigated.     

Grain structure in cathode spot trail of low vacuum arc discharge

Low vacuum arc discharge treatment in 10 Pa is applied to cleaning of a stainless steel plate, the surface of which is covered with an oxide layer. During the discharge, several luminous cathode spots move continuously in random directions on the surface of the stainless steel plate. They remove the oxide layer owing to their high energy density and leave their trail on the sample surface. Microscopic observation reveals a chain structure of metallic grains along the center of the cathode spot trail. Some chemical agents put on the oxide layer before cleaning affect on the size and the number density of the grain, which leads to the different surface roughness after treatment.     

Material and surface processing in J-PARC vacuum system

All systems comprising the Japan Proton Accelerator Research Complex (J-PARC), namely, the 400 MeV linac, 3-GeV rapid-cycling synchrotron, and 50-GeV synchrotron, were completed in 2009 and are now being used to supply high-power proton beams to secondary particle users. In order to minimize maintenance and shorten the pump-down and conditioning period, an ultra-high vacuum of 10⁻⁵ Pa or lower is required for the vacuum system. Here we present a review of the surface processing methods employed and the results of outgassing measurements for the components used in the vacuum system made from the following materials: electroformed copper, alumina ceramic, titanium, and stainless steel. The vacuum performance of these materials during accelerator operation is also reported.     

Charakterisierung der Oberflächenmodifikation von Edelstahlproben nach Elektronen- und Ionenbombardement mittels REM,AES und XPS

The interaction of an inert or reactive gas plasma with the surface of stainless steel was investigated with the aim, to modificate the surface and to influence by this the outgassing rate of the material. This question is especially interesting in applications of these materials in large UHV devices, where a heat treatment of surfaces at the vacuum side is not favourable because of the high energy costs. The investigated samples were exposed to the influence of electrons, argon and oxygen ions either in a DC glow discharge or in a microwave discharge. After this pretreatment the surfaces of the samples were investigated with respect to the topography and the chemical composition (depth profile) by Secondary Electron Microscopy (SEM), Auger Electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS). These surface modifications as a result of the different treatments of the samples were correlated with the measurements of the outgassing rate.     

An overview of methods to suppress hydrogen outgassing rate from austenitic stainless steel with reference to UHV and EXV

The present review of methods reveals some new theoretical aspects and findings concerning suppression of the hydrogen outgassing rate q_out from austenitic stainless steels in relation to the ultrahigh vacuum and extreme high vacuum.The review includes work on thermal treatment and modelling, permeation rate and the role of surfaces, diffusion barriers and coatings.     

Friction in near-surface regions of plasma-nitrided and post-oxidized plain steel at various hydrogen contents

We investigated the low load friction behavior of plasma post-oxidized, plasma- nitrided AISI 1045 plain steel, using unidirectional sliding tests. The hydrogen content in the post-oxidation plasma was varied between 0 and 25%. The nitrided or oxidized layer thicknesses ranged from approximately 340-380 μm or 0.7-1.1 μm, respectively. The outermost iron oxide layer decreases the friction, whereas the underneath iron nitride layer increases the mechanical strength. The incorporation of hydrogen in the oxidative plasma mixture allows to control the type of iron oxide phase. It is observed that the presence of a superficial magnetite layer leads to a decrease of the friction coefficient with respect to the non-oxidized nitrided steel. The results are interpreted on the lights of crystal chemistry and with a model to explain the in-depth effects of hydrogen in the oxidative plasma.     

High intensity laser effects on stainless steel in a vacuum

The interaction of AISI 304 stainless steel with an intense Q-switched neodymium-doped yttrium aluminium garnet laser beam (λ=1.06 μm) was studied in an ultrahigh vacuum system using Auger electron spectroscopy and quadrupole mass spectroscopy. Laser etching of the sample was observed and a comparison was made with the ion-etching profile of the same sample. Owing to the selective evaporation of oxygen from the liquid layer of stainless steel produced by the laser irradiation, an ultrathin film of elemental iron was formed on the underlying oxide. Moreover diffusion of chromium from the bulk to the surface occurs, which cannot be accounted for by the segregation mechanism that has been proposed to account for surface segregation in some ion-implanted materials.     

类金刚石薄膜在不锈钢表面结合强度及耐腐蚀性研究

类金刚石(DLC)薄膜与不锈钢的结合强度是DLC薄膜应用于血管支架表面改性的关键技术问题.利用磁过滤阴极真空弧源沉积方法在316L不锈钢表面沉积DLC薄膜,研究沉积时基体偏压、薄膜厚度以及钛过渡层对DLC薄膜与基体结合强度的影响.研究结果表明,316L表面制备相同厚度的DLC薄膜,采用-1000V脉冲偏压制备的薄膜结合强度明显优于-80V直流偏压下制备的DLC薄膜;随着DLC薄膜厚度的增大,DLC薄膜与316L基体的结合力下降;316L不锈钢表面制备一层100nm的钛过渡层之后可以改善DLC薄膜的结合状况,并且经过20%的拉伸变形后,DLC薄膜完整,耐蚀性优于未表面处理的316L不锈钢.以上研究结果表明,磁过滤阴极真空弧源方法制备DLC薄膜与316L结合强度高,可以有效的提高316L的耐腐蚀性,是一种具有应用前景的血管支架表面改性方法.     

Abrasive wear resistance of titanium- and nitrogen-implanted 52100 steel surfaces

The wear resistance of titanium- and nitrogen-implanted 52100 bearing steels was measured by an abrasive wear technique with a depth resolution of 20–30 nm. Titanium-implanted surfaces were extremely resistant to wear against fine (1–5 microm) diamond abrasion, which suggests a very hard surface layer. Nitrogen-implanted surfaces, by contrast, wore at the same rate as non-implanted surfaces. Wear resistance versus depth profiles of titanium-implanted surfaces followed the concentration versus depth profile of the implanted titanium. Auger depth profiles indicated a large concentration of carbon (≈20 at.% maximum) distributed with a diffusion-like profile from the titanium-implanted surface into the bulk. The carbon was identified by Auger line shape analysis as a titanium carbide, and the wear resistance of the surface was attributed in part to its presence.     

Corrosion of bio implants

Chemical stability, mechanical behaviour and biocompatibility in body fluids and tissues are the basic requirements for successful application of implant materials in bone fractures and replacements. Corrosion is one of the major processes affecting the life and service of orthopaedic devices made of metals and alloys used as implants in the body. Among the metals and alloys known, stainless steels (SS), Co-Cr alloys and titanium and its alloys are the most widely used for the making of biodevices for extended life in human body. Incidences of failure of stainless steel implant devices reveal the occurrence of significant localised corroding viz., pitting and crevice corrosion. Titanium forms a stable TiO₂ film which can release titanium particles under wear into the body environment. To reduce corrosion and achieve better biocompatibility, bulk alloying of stainless steels with titanium and nitrogen, surface alloying by ion implantation of stainless steels and titanium and its alloys, and surface modification of stainless steel with bioceramic coatings are considered potential methods for improving the performance of orthopaedic devices. This review discusses these issues in depth and examines emerging directions.     

真空管道TiN膜热出气率实验研究

简要叙述了小孔流量法测量材料出气率实验的原理和实验装置，给出了不锈钢溅射镀TiN膜在不同情况下的热出气率，并对影响不锈钢溅射镀TiN膜热出气率情况的各种因素进行了分析，为使用溅射镀TiN膜表面处理的储存环真空室的设计提供了依据。     

Modifizierung der Gasabgabe von Edelstahloberflächen durch Ionenimplantation

Several years ago there were established a new ion-implantation technique, the so called Plasma source ion-implantation. This technique was applied on stainless steel samples to implant ions of nitrogen or oxygen into the surface in a controlled manner and to create barrier layers of nitrides or oxides, respectively. With the help of surface-analytical methods it could be shown that oxygen or nitrogen were incorporated homogeneously in a certain depth region below the outermost surface. Some measurements of the outgassing behavior of these plasma treated surfaces will be shown. The results are discussed as originated from the surface modification by the plasma treatment and the creation of the implantation layer.     

Outgassing from stainless steel and the effects of the gauges

The true outgassing from surfaces is often masked by the production of gases and pumping within the measuring gauge. Quadrupole mass analysers have been used to measure the outgassing from carefully prepared samples of stainless steel. By using an isolation pressure rise technique coupled to non-evaporable getter pumping, the problem of production of methane by the gauge is overcome and it has been possible to measure the outgassing of methane to very low levels. The specific outgassing rate of methane from 316 L stainless steel is found to be ?5×10⁻²² mbar l s⁻¹ cm⁻². The outgassing of the other gases has been measured using several gauges. The specific outgassing of hydrogen is found to be 4.5×10⁻¹⁵ mbar l s⁻¹ cm⁻² and the total of all other gasses amounted to no more than 10% of this figure. Although the measurements of the other gases are more ambiguous than those for methane, it is concluded that, in all probability, only hydrogen is outgassed from stainless steel.     

低温绝热气瓶真空寿命模拟试验研究

提出了对绝热气瓶真空夹层逐次充入模拟气体进行绝热气瓶漏气和材料放气的真空寿命模拟试验评价方法。试验实例表明:低温绝热气瓶静态蒸发率在低温下夹层压力>5×10^-2Pa后迅速上升,即5×10^-2Pa可视为夹层真空寿命终结的拐点(或阈值)。5A分子筛在液氮温度下对氮具有巨大的吸附潜力,对氢表现出弱的吸附能力。真空绝热夹层的材料放气对真空寿命的影响远远大于漏气的影响,提高绝热气瓶真空寿命的技术途径是减小夹层材料的放气率和改善内置吸附剂对氢的吸附能力。模拟试验能直观、实际、准确地研究漏气和放气对真空寿命诸因素的影响,为确定切合实际的设计参数和工艺提供参考数据,进而推广用于各类真空绝热型低温容器的真空寿命评价和应用。     

Mass-transport driven by surface instabilities under high-flux, low-energy nitrogen ion irradiation at elevated temperatures

Flux effects in ion nitrided AISI 304 stainless steel have been investigated in an attempt to understand the mechanism of nitrogen transport. It is concluded that an interaction between a highly activated surface layer, the internal interfaces and the bulk is critical. Under conditions of non-equilibrium present on the surface, the nitrogen atoms are driven into the grain boundaries and highly compressive stress is formed. The stress relaxation processes initiate plastic flow of atoms in the grains and a corresponding flow of nitrogen atoms.