The use of infrared thermography in the corrosion science area

The use of infrared (IR) cameras has in recent years gained interest as a non‐destructive testing (NDT) technique in a number of different research fields. All objects with a temperature above absolute zero emits IR radiation, and the amount of radiation increases with temperature. Infrared thermography is a non‐contact technique with high speed which allows inspection of large areas in a relatively short time. In the present work different aspects of IR thermography are described and discussed. Further, corrosion panels with defects, i.e. blisters and filiform corrosion, have been investigated with pulsed thermography. The area of the blisters and filaments, measured with pulsed thermography, have been evaluated, the result obtained have been compared with results from surface profile measurements of the same area. The differences between the results and the limitations of the pulsed thermography are discussed.     

An in situ FT‐IR evaluation of candidate organic corrosion inhibitors for carbon steel in contact with alkaline aqueous solutions

The influence of some organic additives on the anodic behaviour of a carbon steel electrode in contact with alkaline aqueous solutions was studied by in situ Fourier transform infrared (FT‐IR) spectroscopy. FT‐IR spectroscopy allows to obtain information at the molecular level regarding the metal‐electrolyte interface. The following molecules have been considered: (i) benzyldimethylphenylammonium chloride (BDMPAC), (ii) glutamic acid, (iii) triethylenetetramine (TETA), (iv) sodium tartrate and (v) sodium benzoate. Potential‐dependent spectra have been recorded for the different investigated systems. Quantitative information about the formation kinetics of corrosion products was derived by numerical analysis of the peak area as a function of the applied potential for the different systems investigated.     

Characterization of rust phases formed on low carbon steel exposed to natural marine environment of Chennai harbour – South India

The corrosion behaviour of low carbon steel exposed to marine atmospheric, splash and immersion zones has been systematically studied by exposing steel specimens for a period of 12 months at the boat basin corrosion station of Chennai harbour, Chennai, Tamil Nadu, South India. The literature on similar work has been thoroughly reviewed which led to the initiation of this study for the first time at this harbour. The corrosion product (rust) on the specimens at 1, 2, 3 and 12 months was obtained and characterized by Fourier transform infrared spectroscopy (FT‐IR) and X‐ray diffraction (XRD) analysis. Acaganeite was the rust phase identified in the splash zone as revealed by the FT‐IR and XRD analysis. The other dominant phases were lepidocrocite, goethite and ferroxyhite. Small amounts of magnetite were also found to be present. The transformation of phases was observed in this investigation and discussed. A remarkable difference in the FT‐IR and XRD patterns of the corrosion products at the splash and immersion zones were noticed and the corresponding phases formed were reported in this paper. The rate of corrosion in all the three zones was compared.     

基于数理统计的无损检测过程质量控制

无损检测与评价的可靠性取决于检测过程的可靠性。采用适宜的质量控制技术对检测过程的抽样、检测人员、检测仪器、检测数据和缺陷评定等因素进行分析与控制，可以提高检测与评价结果的准确性及可靠性。简要介绍了统计抽样、测量系统分析、不确定度评定、故障树与事件树分析等质量控制技术的理论及应用方法，并结合无损检测与评价过程进行了讨论。     

HA涂层的电结晶-水热合成及其附着性与结构稳定性探讨

采用电结晶水热合成法在室温条件下从含钙、磷离子的电解水溶液中电结晶沉积磷酸钙涂层,经蒸汽处理和真空煅烧后在钛合金基体上获得羟基磷灰石生物涂层．用ＳＥＭ,ＸＲＤ,ＩＲ分析了涂层的组织、结构和化学组成,分析了羟基磷灰石涂层的形成原理,用粘结拉伸法测量了涂层的结合强度,并在模拟体液中研究了涂层的生物化学稳定性．结果表明：电结晶形成的ＣａＨＰＯ４·２Ｈ２Ｏ涂层经水热处理后,转变为羟基磷灰石．涂层由针状晶体组成,均匀性和粘结性好,纯度高;涂层的结合强度在１５ＭＰａ左右,涂层在模拟体液中浸泡１２个月后化学成分并未发生改变,但质量因降解而减少．     

Automatic inspection of gas pipeline welding defects using an expert vision system

Automatic inspection of welded gas pipelines is desirable because human inspectors are not always consistent evaluators. In addition, automatic inspection decreases the cost of inspection process and improves the inspection quality. In this paper, an expert vision system for automatic inspection of gas pipeline welding defects from radiographic films is presented. The proposed system has been established in the Metrology lab, Mansoura University, Faculty of Engineering. The software, named AutoWDI, is fully written in lab using Microsoft Visual C++ and is ready to run on any Windows environment. The proposed vision system is used to capture images for the radiographic films then applies various image processing and computer vision algorithms to recognize the defects and to make acceptance decisions according to international standards. The expert system is based on a knowledge base, which was gathered from specialists, textbooks and international standards. The proposed system is capable of identifying and testing the main types of welding defects (11 defects) in gas pipelines welded by shielded metal arc welding.     

An implementation of drive key cellular manufacturing

The drive key is one of the most important high-precision components of aircraft braking systems. In this paper, a cost effective drive keys manufacturing process is developed. This proposed manufacturing process makes use of near-net-shape manufacturing, computer numerical control (CNC) machining, and cellular manufacturing methods. To make the proposed process a reality, proper engineering with the proposed parts along with group technology are applied to the product design in conjunction with the proposed manufacturing methods. In addition, a general spreadsheet program is developed for each style of fixture modules to assist in part program coding. Moreover, statistical process control (SPC) is implemented to verify product quality and accept the product at the point of manufacture. It is observed that the implementation of the proposed drive key cellular manufacturing process results in a tremendous improvement in quality, throughput and productivity as well as a drastic reduction in manufacturing operations, workholding fixtures, cutting tools, and inspection media.     

Propane gas leak detection by infrared absorption using carbon infrared emitter and infrared camera

The present study investigated the ability of a system using a carbon infrared emitter (CIE) and an infrared (IR) camera to detect a combustible gas, propane. The CIE transmitted infrared at wavelengths ranging from 1 to 5 μm, and the infrared absorption band of propane gas (3.37 μm) was obtained using a bandpass filter to remove other infrared wavelengths. The intensity of infrared radiation passing through the propane gas decreased as a result of infrared absorption. A clear, real-time image of the gas leak was also obtained using this system. Furthermore, a hazard evaluation of the leakage propane gas was made from a correlation between infrared intensity and the concentration–pathlength product.     

Microstructural characterization of porous thermal barrier coatings by IR gas porosimetry and sintering forecasts

It is known that the thermal diffusivity of plasma sprayed coatings is quite sensitive to the operating conditions, namely the composition and pressure of the operating atmosphere. This makes it possible, in principle, to obtain information, in a non-destructive way, on the microstructure of thermal barrier coatings (TBCs) from thermal diffusivity measurements. An experimental assessment of this idea is presented in this paper. The microstructure of as-sprayed and sintered free-standing atmospheric plasma sprayed YPSZ TBC samples have been characterized by a new technique, named infrared (IR) gas porosimetry, as well as by mercury intrusion porosimetry and image analysis. The results from these different techniques have been compared. Furthermore, the microstructure and thermal diffusivity of sintered samples have been compared with the sintering forecasts produced by Cipitria’s sintering code coupled with the Bruggeman model for thermal diffusivity estimation. Sample-to-sample variations have been discussed and uncertainties in experimental techniques have been analysed. Conditions for accurate microstructural estimations have been obtained and suggestions on the reliability of the statistical evaluation are provided.     

压力容器无损检测技术综述

综述压力容器原材料、压力容器制造和使用过程中采用的无损检测技术，包括超声、射线、磁粉、渗透、涡流、声发射、红外线、漏磁和磁记忆检测技术。并论述采用这些检测技术的目的。     

Digital image analysis of X-ray and neutron radiography for the inspection and the monitoring of nuclear materials

The article shows the digital image analysis of X-ray and neutron radiography (NR) ad hoc developed for the inspection and monitoring of nuclear samples, used in several experiments at the High Flux Reactor of the Institute for Energy (JRC-Petten). This application is valuable not only in the characterization of the sample and of the experimental assembly, but also in acquiring information on the sample behaviour during and after the irradiation.The inspection foresees the X-ray radiography of the sample in order to detect the eventual presence of fabrication defects. During and/or after the irradiation, NR helps to understand the sample behaviour under irradiation (such as swelling, disintegration). NR can also be performed before the irradiation for comparison with NR during the irradiation and with the X-ray.The image analysis is used for acquiring qualitative and quantitative information from these inspection techniques at a high level of accuracy.     

Self-feed device behaviour evaluation designed for assessment of operability of coated electrodes

The objective of the present work is to evaluate the effectiveness of a self-feed device for coated electrodes. This device is able to eliminate disturbances from manual operation or the use of automatic control systems during the study of coated electrode behaviour. The conjugation of different methods such as short-circuit time statistical analysis and metallographic analysis (penetration, heat-affected zone, shape and mean distance between successive solidification fronts) together with the analysis of the electric arc and electrode melting parameters allows us to obtain relationships between arc behaviour, mass transfer processes and bead appearance. This permits the extraction of criteria to describe process stability and the behaviour of the feed device employed. An appropriate statistical methodology was obtained to process the ‘duration of the short-circuit’ parameter through an appropriate adjustment of empirical distributions to a log-normal model. The self-feed device for coated electrode welding allows the repeatable and reproducible execution of welding beads in the flat position, keeping the arc length based on physical and chemical characteristics of the electrode during welding trials using 125, 140 and 160 A.     

超声红外热成像无损评估技术

超声红外热成像技术是一种新的无损检测方法,它是利用低频超声脉冲波作用在不同的材料或者结构上,然后通过红外热像仪对被测件在脉冲波激励下产生的局部发热过程进行采集,从而判别被测件中缺陷的有无及其位置。简要介绍了国外超声红外热成像无损评估在金属材料、复合材料和陶瓷材料中疲劳裂纹、分层、脱粘等损伤检测方面的应用情况。     

水性红外隐身涂料制备工艺优化

目的优化水性红外隐身涂层材料制备工艺,提高低发射率红外隐身涂料隐身性能。方法采用红外辐射率测量仪、红外光谱吸收仪等,研究涂层固化温度、涂层表面粗糙度和涂层厚度对低发射率红外隐身涂料隐身性能的影响。结果固化温度对涂层红外发射率和基体树脂红外吸收光谱影响不大,但随着固化温度升高,涂层固化时间明显缩短;随着涂层表面粗糙度的增加,涂层红外发射率增加;表面粗糙材料红外发射率受测试角度影响小于表面光滑材料;在基材上制备不同厚度的涂层,当涂层厚度小于30μm时,涂层红外发射率受基材表面红外发射率影响较大,当大于30μm时,影响较小。结论可以根据实际时间需求选择合适的涂层固化温度,宜选择刮涂方式使涂层表面保持一定的粗糙度,涂层厚度宜为30~40μm。     

The harmonic fitting method for the assessment of the substitute geometry estimate error. Part II: statistical approach, machining process analysis and inspection plan optimisation

The Harmonic Fitting Method (HFM), presented in the first part of this work, is here used to describe the estimate error in statistical terms. In fact, the estimate error can be considered as a random variable that depends on three different random processes: the machining, the part positioning, and the measurement processes. With the HFM it is possible to determine the moments of the estimate error (systematic value and covariance matrix) as a function of the inspection plan. It will be demonstrated that the systematic part of the estimate error derives from the systematic part of the machined surface deviations, and that the random part derives from the variability of the machining and measurement processes. In particular, the causes of the machining process variability will be analysed in terms of harmonics, thus establishing a direct relationship between the machining process and the substitute geometry estimate error. Moreover, the possibility of obtaining the probability density function of the estimate error from the HFM will be analysed, together with the problem of the inspection plan optimisation. The HFM will be used to design the optimal inspection plan for a circular geometric feature, and it will be demonstrated that, when the part positioning is subjected to a rotation uncertainty, the estimate errors of the diameter and of the eccentricity are likely to follow a Gaussian and a Rayleigh distribution, respectively. A real case of turned shafts will be considered, and the HFM optimisation of the inspection plan will be discussed.     

Study of the corrosion behaviour of Cu-10Sn bronze in aerated Na2SO4 aqueous solution

Investigation of the electrochemical behaviour of Cu-10Sn (wt.%) alloy has been conducted in aerated aqueous sulphate solution and compared to that of pure Cu and Sn. Eoc versus time and cathodic and anodic polarizations have been performed as a function of the initial sulphate concentration, the rotation speed of the electrode and the immersion time. The surface layer have been characterized by scanning electron microscopy (SEM) and analyzed by energy dispersive spectrometry (EDS) and Fourier transform infrared spectroscopy (FTIR). The anodic behaviour evidences a Cu dissolution phenomenon on the corrosion layer limited by migration process rather than diffusion. The corrosion process conducts to preserve the original surface of the electrode and conducts to an internal growth at the layer/alloy interface, from the initial surface towards the unaltered substrate. The interphase behaviour is governed by the layer formed at Eoc under the experimental conditions and its evolution during the time. Hydroxyl-oxy and sulphate Cu and Sn compounds recover the surface and confer to the interface a blocking behaviour mainly due to the presence of the tin compounds in the layer. The global interphase behaviour matches the Type-I model of blocking adherent layer with decuprification phenomenon evidenced on archaeological bronzes.     

Analysing the process behaviour of abrasive reaming using an experimental approach

Abrasive reaming is an innovative technique for bore finishing. Despite its widespread use, its process behaviour is still under-explored. Accurate control of bore precision in abrasive reaming is affected by many parameters such as feed rate, stock removal and abrasive grit size. Previous research work in this area concentrated only on key parameters and hence failed to deliver reliable information to improve the process. This paper analyses the process behaviour of abrasive reaming using the data obtained from detailed experiments. The effect and significance of individual factors on the bore geometry were assessed using a statistical approach. Process characteristics such as material removal, sidewall stripping and stick–slip behaviour have been analysed and it is shown that inputs such as grit size, amount of stock removal and dressing type are to be controlled.     

红外光谱在腐蚀研究中的应用与发展

简要地介绍了红外光谱（IR）特征及发展史，着重阐述了其在腐蚀电化学中的应用及发展趋势；展示IR在原位研究腐蚀电化学的界面结构，防腐蚀产品的组分鉴定和腐蚀机理的研究领域中已经取得的令人瞩目的进展。     

Characterization of the process control for the direct laser metallic powder deposition

Direct Laser Metallic Powder Deposition Process is one of the most popular direct additive manufacturing processes which use laser as a heat source to deposit the metallic powder layer by layer for surface modification and fabrication of three-dimensional parts. The properties of the deposited layer, such as microstructure, hardness and dimensional accuracy determine the usage properties of the processed parts. The temperature and size of the melt pool, the cooling rate and the solidification conditions dominate the microstructure, hardness and dimensional accuracy. In this work, a closed-loop process control based on the infrared (IR)-temperature signal was investigated by deposition of thin walls. Process control with constant set-values and path-dependent set-values was tried and compared. The results showed that the process control with a path-dependent set-value can notably improve the homogeneity of the microstructure and hardness as well as the dimensional accuracy of the deposited samples.     

GROWTH OF β-SiC BY rf SPUTTERING ON SILICON SUBSTRATES

1. IlltroductiollSili(.oll t.arbide (SiC) llas beell il1vestigated as a nlaterial with great poteIltial il1 high-p()xxer. high teulperature. and high-f1equel1c} devices, sil1ce it has feat[tres of high break-(l()ttll voltage, l1igll satllratioll t.elocit}…