钨铼热电偶在空气中的热电动热稳定性及其特性研究

为了解决钨铼热电偶在实际使用中遇到的问题，本文探讨了钨铼热电偶在空气中的高温稳定性规律。研究结果发现：钨铼热电偶由于某一极完全氧化而导致材料性质发生了质变，从而引发了与之相应的热电性性质的根本改变；     

高性能钨铼热电偶材料及补偿技术研究

介绍了高性能钨铼热电偶材料制备方法,分析了钨铼热电偶材料热电特性影响因素及其补偿方式,通过EDS、SEM等分析手段,对微量元素分布、材料微观组织等进行表征,探讨了微量元素分布及微观组织与热电特性的关系,同时分析了钨铼热电偶补偿温度对测温精度的影响,该热电偶材料制成的快速偶头现场测试结果显示其稳定性可控制在±3℃以内,具...     

高性能钨铼热电偶材料及补偿技术研究

文章介绍了高性能钨铼热电偶材料制备方法,分析了钨铼热电偶材料热电特性影响因素及其补偿方式,通过EDS、SEM等分析手段,对微量元素分布、材料微观组织等进行表征,探讨了微量元素分布及微观组织与热电特性的关系,同时分析了钨铼热电偶补偿温度对测温精度的影响,该热电偶材料制成的快速偶头现场测试结果显示其稳定性可控制在±3℃以内,具有良好的测温可靠性。     

2500℃高温钨铼套管热电偶

本文介绍难熔金属套管热电偶各组件之间的高温化学相容性试验结果;为减小高温下,绝缘材料电阻下降造成热电势分流的影响。设计了一种特殊结构的绝缘体。根据试验结果,组装成可以使用到2500℃的钨铼套管热电偶,取得了良好的效果。     

同名极比较法在钨铼热电偶丝热电势检测中的应用

文章对同名极比较法在快速测量钢液温度用钨铼热电偶丝热电势检测中的应用进行了探讨。结果表明:同名极比较法适用于钨铼热电偶丝的热电势检测,具有工作效率高、检测成本低、操作简单及测试环境要求低等优势,建立微差热电势数据库后,可以提高钨铼热电偶丝精度等级和配对效率。     

钨铼热电偶元件小型化技术研究

本文研究采用电泳涂层法制作小型钨铼热电偶高温测温元件的可能性和工艺过程，研制的热电偶元件外φ≤1.2mm，测温温度t≥1800℃，全面进行了元件的性能检测。包括热电性能，抗热冲击性能，稳定性和时间响应性能等，并在模拟宇航和核场条件下进行了实际温度测量。此外，作为钨铼热电偶用于高技术领域的一项基础性研究，对高温热电偶制作过程中的材料选配和制作工艺等问题进行了探讨。     

钨铼型热电偶稳定性的研究

在市场上可以买到的钨铼型热电偶的典型样品,是由美国生产的,在氩气保护的条件下标定到2100℃。当初始标定完成以后,使热电偶经受1000℃至2100℃的热循环,并且也使其在氩气条件下退火420小时。比较热电偶在经受热循环和退火处理前后热电势的变化。通常钨/钨—26%铼热电偶在热循环和退火处理后.其热电势显示出有很大的变化。而钨—3%铼/钨—25%铼热电偶其热电势变化最小。另外还对一些用氧化镀(BeO)绝缘和没有氧化铍绝缘的热电偶在氩气、氦气和真空等条件下进行了标定,比较了它们在这些条件下的热电势。     

适用于氧化性介质的钨铼热电偶

用热电偶在氧化性介质中测量高温有很大的困难。最适合于氧化性介质的铂铑-铂热电偶只能用至1600℃。其它贵金属和合金,例如:铱、铱钌、铱铑合金等制成的热电偶热电势均较低,而且很不稳定,价格也极其昂贵。不同含铼量的钨铼合金制热电偶可供测温至2400℃,但它只能在真空或还原性介质中使用,由于钨在高温下与氧发生活性互反应,故这种热电偶不适于在氧化性介质中应用。实验表明,如果将热电偶的工作端敷一层铱保,护层(见附图),其未用铱保护的偶丝部分装在耐火陶瓷管内,则钨铼合金热电     

钨铼热电偶的稳定性

除了热电势绝对值和热电偶对温度变化的敏感性外,热电偶的热电势稳定性也是热电极材料的主要性能之一。文献指出,钨铼合金基的BP5/20、BP10/20、BP15/20热电偶于2000℃在真空和氩气氛中的稳定性显得不足。苏联生产了一种在原有的BP5合金中添     

基于高温黑体炉的钨铼热电偶校准方法研究

基于中国计量科学研究院的高温黑体炉设计了一种适用于钨铼偶等高温热电偶的校准方法。优化设计的均温块测温孔轴向均匀性20mm范围内小于0.5℃,优选的测温孔与中心孔的辐射温度差异可达到小于0.5℃。经铂铑10-铂热电偶验证了基于高温黑体炉的校准方法,在800~1300℃与S型热电偶标准热电势间差异小于0.5℃,不确定度评估为0.8~1.5℃,k=2。在800~1900℃范围内,测试了多只不同来源的C型钨铼偶热电势并考核了偶丝校准前后的均匀性,实验结果表明,钨铼偶丝与国际标准钨铼偶热电势的差异基本保持在1%以内,校准不确定度为3.7~13.0℃,相对不确定度为0.7%t (t为温度),k=2。     

真空热处理使用的新型温度传感器

简述了钨铼热电偶及复合管型铠装热电偶的性能及特点，着重讨论了渗碳炉，铜、铝等液态金属熔体温度检测技术，研制出真空炉，渗碳炉专用实体热电偶，铜水，铝液及高温盐浴炉连续测温用热电偶，成功地用于易普森工业炉，“一汽”，“二汽”、瓦房店轴承集团，贵州铝厂等在线温度检测，实践结果表明，热处理用温度传感器不仅能国产化，还可以进入国际市场。     

高精度金-铂热电偶的制作和热电稳定性研究

金-铂热电偶是采用纯金和纯铂电极制成,长期使用过程中是否能够保持温度与热电势关系稳定是其准确测温的关键.首先,对热电极丝材进行剪切、清洗、退火并焊接组装成热电偶;然后,再对制作成的热电偶进行退火实验,热电偶在其使用上限965℃附近累计退火时间700 h,在银凝固点的稳定性达到±0.02℃.在制造热电偶过程中,采取了传统...     

A gold-platinum thermocouple

Summary Since the homogeneity of gold is much higher than that of platinorhodium, the gold-platinum thermocouples provide considerably more accurate temperature measurements than platinorhodium-platinum thermocouples. The high degree of homogeneity of gold is especially valuable when small temperature differences are measured. Another important advantage of the gold-platinum thermocouples as compared with the platinorhodium-platinum ones is their higher thermal emf and lower electrical resistance. The defects of the new thermocouple are its high thermal conductivity, tendency to acquire plastic strains and the low melting point of gold as compared with platinorhodium. These defects are absent in another thermocouple made of pure metals, the rhodium-platinum thermocouple, which we propose to analyse in the future.     

Thermoelectric Characteristic of High-Temperature Thermocouples W5%RE/W20%RE

In the temperature range (900 to 2800) K, there has been confirmed compliance with the existing national standards for thermocouple wires W5% Re/W20%Re (type A) produced in Russia. The homogeneity within a lot of wires was evaluated by measuring the emf deviations from the corresponding reference function of thermocouples constructed from the front and the rear sections of paired coils of wires. The diameter of the wires amounted to 0.35 mm and 0.5 mm. Stability indicators were thermal emf changes after annealing for 2 hours at 1773 K. It was found that the inhomogeneity of thermoelements did not exceed (4 to 5) K for paired wire coils with a thermoelectric stability within a temperature equivalent of (1.0 to 1.5) K. EMF deviations from the reference table values for the thermocouples investigated did not exceed 1 % in the temperature range of (900 to 2773) K. Such deviations meet the requirements of the new draft of IEC standards 60584-1 and 2. Thermocouples were calibrated in four laboratories by comparison with various standard temperature gauges (type B thermocouple, radiation pyrometer, standard specimens of thermoelements). Measurements were carried out under vacuum, argon, and hydrogen. Depending on the calibration method, the expanded uncertainty of the measurements at 1773 K varied from (2.8 to 8) K.     

Stability Studies of a New Design Au/Pt Thermocouple Without a Strain Relieving Coil

The performance of a simple, new design Au/Pt thermocouple developed by NMIA is assessed. This thermocouple is proposed as a more accurate replacement, over the temperature range from 0 to 1,000°C, for the commonly used Type R and S industrial transfer standards, in a robust form familiar to industrial calibration laboratories. Due to the significantly different thermal expansions of the Au and Pt thermoelements, reported designs of the Au/Pt thermocouple incorporate a strain-relieving coil or bridge at the thermocouple junction. As the strain relieving coil is mechanically delicate, these thermocouples are usually mounted in a protective quartz tube assembly, like a standard platinum resistance thermometer (SPRT). Although providing uncertainties at the mK level, they are more delicate than the commonly used Type R and S thermocouples. A new and simple design of the Au/Pt thermocouple was developed in which the differential thermal expansion between Au and Pt is accommodated in the thermocouple leads, facilitated by a special head design. The resulting thermocouple has the appearance and robustness of the traditional Type R and S thermocouples, while retaining stability better than 10 mK up to 961°C. Three thermocouples of this design were calibrated at fixed points and by comparison to SPRTs in a stirred salt bath. In order to assess possible impurity migration, strain effects, and mechanical robustness, sequences of heat treatment up to a total of 500 h together with over 50 thermal cycles from 900°C to ambient were performed. The effect of these treatments on the calibration was assessed, demonstrating the sensors to be robust and stable to better than 10 mK. The effects on the measured inhomogeneity of the thermocouple were assessed using the NMIA thermocouple scanning bath.     

In Situ Thermocouples in Macro-Components Fabricated Using SALD and SALDVI Techniques. III. Fabrication and Properties of the SiC/C Thermocouple Device

Fabrication of a SiC/C thermocouple embedded in an arbitrarily-shaped SiC macro-component has been demonstrated using an integrated Selective Area Laser Deposition (SALD) with the closely related Selective Area Laser Deposition Vapor Infiltration (SALDVI) process. SALD is used to make the embedded thermocouple devices in situ and SALDVI to fabricate the macro-components. The thermocouple elements, silicon carbide and carbon lines, and the electrical insulation layer, Si₃N₄, have been deposited from tetramethylsilane (TMS), acetylene, and a gas mixture of TMS and ammonia, respectively. It is found that the fabricated in situ thermocouples respond sensitively to temperature variation. Furthermore, the electric signal of the embedded thermocouple is very stable and reproducible in response to thermal cycling. This is not the case when the thermocouple is not embedded in the SiC matrix because of the oxidation of the thermocouple elements.     

薄膜热电偶热电特性分析与试验

薄膜热电偶具有体积小、操作简便、准确度高等优点,在精确测温领域显出了极大优势。采用磁控溅射法生产的热电偶在材料组合上几乎是无限的。本文对Ni CrNi Si薄膜热电偶、Ni Cr SiNi Si Mg薄膜热电偶静态下的重复性、使用寿命、温度上限等进行对比、分析,以便在使用中可以更好地"因地制宜"。与大连某高校制作的薄膜热电偶进行对比试验,验证制作工艺对薄膜热电偶性能的重要影响。薄膜热电偶作为一种新型热电偶,在发动机叶片等特殊部件表面测温领域具有广泛的应用前景。     

Comparative Study of Pt/Pd and Pt–Rh/Pt Thermocouples

The Pt/Pd thermocouple has demonstrated superior thermoelectric drift and homogeneity performance over conventional Pt–Rh/Pt thermocouples. Here, we present a systematic comparison of the drift and homogeneity performance of Pt/Pd and Type R thermocouples by ageing the thermocouples at 1350 °C for a total of 500 h and measuring the performance at regular intervals during this time. The thermocouples studied were one Pt/Pd thermocouple, one Type R thermocouple and one ‘special’ Type R thermocouple which was given the same preparatory annealing treatment as the Pt/Pd thermocouple prior to use. The thermoelectric stability of each thermocouple was measured at the freezing point of Ag (961.78 °C) and the melting point of Co–C eutectic (1324.29 °C). The thermoelectric homogeneity of the thermocouples was also measured. Two difference methods were used by withdrawing the thermocouple from the Ag cell and by moving a localized heat source along the thermocouple. The long-term drift of the Pt/Pd thermocouple was around 50 mK (Ag) and 65 mK (Co–C) after the first 100 h ageing at 1350 °C, followed by a further 25 mK (Ag) and 35 mK (Co–C) over the subsequent 400 h ageing. This drift performance and inhomogeneity were an order of magnitude lower than for the two Type R thermocouples. The Type R thermocouple which was given the ‘special’ preparatory treatment was about 50 % more stable than the conventional Type R thermocouple.     

快速钨铼热电偶的测温误差

本文用热电偶误差计算的通用方法（极限误差表达法）分析了构成快速钨铼热电偶测温误差的因素，从量的角度探讨了各因素对总的误差的影响，对如何认识快速钨铼热电偶的测温精度，提出了可供参考的观点。     

Assessment of Temperature Measurements Using Thermocouples at NIS-Egypt

Thermocouples are increasingly used in industry and research. For many industrial heating processes, particularly those carried out at high temperatures, a thermocouple is the most convenient and simple instrument for temperature measurement. In some instances, it is the only feasible method. The aim of this study is to select and recommend the best thermocouples from both base and noble metals to users in industrial and scientific institutions. Different types of thermocouples and calibration methods are described. From this work, the Nicrosil–Nisil thermocouple has been proposed as the best base metal thermocouple and the Au/Pt thermocouple is the most recommended as a substandard up to 1,000 °C.