新制高温铂电阻温度计退火实验研究

合理的退火是提高铂电阻温度计稳定性的有效途径.本文选取9支新制高温铂电阻温度计作为研究对象,在970℃条件下进行了超过1000h的退火处理,研究退火对高温铂电阻温度计Rtp的影响.实验结果表明,在970℃下退火600h以上能够有效消除新制铂电阻的应力,相比于1010℃退火,970℃退火需要更长退火时间.     

退火温度和退火时间对精密铂电阻温度计影响分析

退火处理是提高温度计稳定性,保持温度计测量准确的有效方法。不同标准对于温度计的退火要求都有所不同,根据需要选择合适的退火温度和退火时间,不仅能够保障温度计的使用,而且能够提高效率节约成本。科学合理的退火时间和退火温度对于精密铂电阻温度计具体良好的效果。     

新型退火炉的研制

研制了新型的退火炉,建立了ITS-90温标定义标准铂电阻温度计检定分度中必须的退火装置.采用先进的加热和控温技术及合理有效的加热器绕制方式,使用铠装加热丝保证绝缘电阻符合要求且无漏电,绕制后加热丝牢固不脱落,杜绝长期使用后温场变化不稳定的现象.炉温呵达700℃,稳定性好,垂直温场优于1.0℃,可用于标准铂电阻温度计的退火,或者用于提供较为稳定的温度源.     

精密铂电阻温度计的校准方法

介绍了精密铂电阻温度计的特性及0~660.323℃温度范围内精密铂电阻温度计的校准方法。提出对测量上限温度高于450℃的精密铂电阻温度计可参考使用说明书要求进行上限温度退火,进行定点法校准时,可采用熔化点温坪替代凝固点温坪,对于无法进行定点法校准的精密铂电阻温度计,可采用比较法校准及采用简化公式计算各项参数的可行性,同时指出自热效应对测量的影响。     

-80～300℃铂电阻温度计在0℃的热迟滞性研究

针对两种不同类型的工业铂电阻温度计(IPRTs),使其在-80℃和300℃下恒温一定时间后再测量其0℃下的电阻偏移,由此来确定其在该温度下的热迟滞性。试验结果表明:薄膜型铂电阻温度计在0℃的热迟滞性远大于铂丝型铂电阻温度计,并且随着测量次数的增多,热迟滞性会逐渐减小。     

新型高温铂电阻温度计的研究 Ⅱ、试验研究

对研制成功的片状骨架结构高温铂电阻温度计进行了持续四年的试验研究。试验结果表明这种温度计的各种性能都很好,并突破了国外一些长期没有解决的技术难关。在1100℃退火,平均每百小时R_0的变化换算为温度约为1mK,快速热循环后(经中温补充退火)R_0的变化换算为温度也不超过1mK。温度计具有良好的抗震性能和热性能。在1064℃时的绝缘泄漏电阻大于27MΩ。石英套管的析晶问题已基本解决。     

铂电阻温度计稳定性的研究

铂电阻温度计是ＩＴＳ -１９９０国际温标中规定的内插仪器 ,也是复现保存温标及温标传递的必要仪器。同时在对各类水银温度计、工业铂电阻温度计等温度传感器及仪表的检定时都是最常用的标准 ,所以铂电阻温度计的稳定与否是非常重要的。铂电阻温度计的稳定性与多种因素有关 ,如制作温度计使用的铂丝均匀性、纯度及工艺 ,温度计的制作过程工艺及退火 ,充气处理 ,新制温度计的退火处理 ,温度计的使用等。这里主要对各类温度计的退火及使用中稳定性的变化做一些分析研究。一、铂电阻温度计的稳定性国际上评定铂电阻温度计的稳定性 ,主要是看其…     

一种高精度薄膜铂电阻温度计测量迟滞性的研究

为了研究热迟滞性对工业铂电阻温度计测量不确定度的影响,选取了8支高精度铂电阻温度计进行实验。在-50～150℃内,选择3个温度区间,采用两种标准方法(IEC 60751,ASTM E644)测量水三相点(0.01℃)和所选温度范围内的中间点的迟滞性变化。实验结果表明:4支薄膜铂电阻温度计在两种标准方法测量下,随着温度区间跨度增大,热迟滞性影响增大,IEC 60751标准方法测量的热迟滞性最大值为14.2mK,ASTM E644标准方法测量的热迟滞性最大值为20.5mK;选取4支铂丝铂电阻温度计在温度范围为-50～150℃测量时,IEC 60751和ASTM E644标准方法测量的热迟滞性数据最大值分别为1.1mK和0.9mK;铂丝铂电阻温度计热迟滞性明显小于薄膜铂电阻温度计。     

铂丝位错特性对标准铂电阻温度计稳定性影响的研究

铂丝的位错是影响标准铂电阻温度计性能稳定性的重要因素之一。从微观角度出发,借助X射线衍射(XRD)分析方法,开展了退火时间对铂丝位错密度影响的研究,并利用标准铂电阻温度计退火实验数据进行了验证。结果表明:实际用于标准铂电阻温度计直径为0.07mm的新制铂丝(纯度99.999%)平均位错密度随着退火时间呈指数减小,经过100h退火后位错密度从1012cm^-2下降到1011cm^-2,300h后其位错密度基本保持稳定;新制标准铂电阻温度计在退火前300h其水三相点电阻值明显减小,退火300h后水三相点值变化量小于3mK并趋于平稳,此结果从热处理时间上与铂丝位错实验结果基本吻合。研究结果为标准铂电阻温度计制作工艺的提升及计量检定规程的修订提供技术支撑     

离子束外延生长(Ga,Mn,As)的退火研究

利用俄歇电子能谱(AES)和X射线衍射(XRD)分析了室温条件下离子束外延生长Ga、Mn、As样品,在不同的温度条件下进行退火后组分和元素分布的变化。结果表明退火有助于样品内部元素的均匀分布,温度为400℃会导致MnO2和Ga5.2Mn的结晶。     

新制标准铂电阻温度计退火特性理论模型及验证

根据再结晶动力学理论,对新制标准铂电阻温度计(SPRT)首次退火过程中水三相点电阻值随时间的变化规律建立了理论模型,得出无量纲电阻值变化具备指数函数特征及双对数无量纲电阻值变化函数的线性特性.基于15支SPRT在660℃退火的实验数据获得了退火参数和退火指数变化范围及平均值.理论模型计算结果表明,1 000 h后的SP...     

Development of the Triple-Point-of-Argon System

A triple-point-of-argon system was developed to realize the argon triple-point temperature defined in the International Temperature Scale of 1990 (ITS-90) and to calibrate long-stem standard platinum resistance thermometers (SPRTs). The system structure, the techniques for realization of the triple-point temperature, and the testing results are presented in this paper. In this system, there is a central argon cell that includes four re-entrant wells with an immersion depth of 160?mm which can be used to calibrate four long-stem SPRTs simultaneously. A high-accuracy temperature controller is used to control the realization process of the argon triple-point temperature plateau. The argon triple-point plateau can be easily realized with this system. The influence of different experimental parameters on the triple-point-of-argon plateau was investigated and is discussed. The testing results show that the duration of the plateau can be over 100?h with the temperature change less than 0.05?mK. The temperature homogeneity of the four re-entrant wells was tested. The immersion profile of the system was measured, and the measurement results were compared with the ITS-90 hydrostatic values. The uncertainty analysis shows that the uncertainty of the argon system is 0.25?mK (k = 2).     

Uncertainties in the SPRT Subranges of ITS-90: Topics for Further Research

The CCT has completed the guide summarizing the uncertainties in the realization of the SPRT subranges of ITS-90 between the triple point of neon (24.5561 K) and the freezing point of silver (961.78 °C). This article identifies aspects of standard platinum resistance thermometry where either data or models are lacking and further research is required. In the calibration of SPRTs, the two main concerns are the need for data on liquidus slopes for the different impurities in the fixed points and improved understanding of the impact of the thermal environment of the fixed point on the realized temperature. In the use of SPRTs, the two largest sources of uncertainty are Types 1 and 3 non-uniqueness and oxidation. The causes of Type 3 non-uniqueness are not yet understood, especially at low temperatures, and there is a paucity of data for the high-temperature subranges. In respect of oxidation, there is a need for validation of the models developed in the 1980s, especially in light of the reduced partial pressure of oxygen used in modern SPRTs. A range of other effects including vacancy effects in SPRTs, isotopic effects in fixed points, and improved statistical methods are discussed.     

准绝热密封氩三相点复现装置

氩三相点作为国际温标ITS-90的重要低温固定点,在国家基准量值传递中有着重要的意义。中国计量科学研究院研制了基于准绝热原理的密封型氩三相点装置,能够对长杆铂电阻温度计进行氩三相点高精度复现,并且通过开发自动控制与测量软件实现了实验过程自动化测量与控制。实验结果表明,使用新研制的密封氩三相点装置使氩三相点的温坪时间提高到23 h以上,其中在16 h的温坪变化在0.2 mK以内,同时温坪复现性达到0.1 mK以内,成功解决了恒定热流法氩三相点复现过程中温坪时间短、复现难度大等问题,保证国家基准量值传递的准确性。     

磷的非平衡晶界偏聚现象及对回火脆性的影响

为确定304L钢中P的偏聚特征,分析了Briant在俄歇能谱(AES)下得到的磷晶界偏聚浓度.研究表明,经1100℃固溶1h、水淬后的304L不锈钢,不仅在700℃恒温时效过程中出现磷的晶界偏聚浓度峰值,并在500、550、600、650、700℃分别恒温时效100h后,600℃处发现磷的晶界偏聚浓度峰值.分析发现,磷在304L钢中发生了非平衡晶界偏聚.通过对磷非平衡晶界偏聚恒温动力学特征的讨论,提出了回火脆性的非平衡晶界偏聚机理.     

Calculating SPRT Interpolation Error

Interpolation error is a major source of uncertainty in the calibration of standard platinum resistance thermometer (SPRT) in the subranges of the International Temperature Scale of 1990 (ITS-90). This interpolation error arises because the interpolation equations prescribed by the ITS-90 cannot perfectly accommodate all the SPRTs natural variations in the resistance–temperature behavior, and generates different forms of non-uniqueness. This paper investigates the type 3 non-uniqueness for fourteen SPRTs of five different manufacturers calibrated over the water–zinc subrange and demonstrates the use of the method of divided differences for calculating the interpolation error. The calculated maximum standard deviation of 0.25 mK (near \(100\,^{\circ }\hbox {C}\)) is similar to that observed in previous studies.     

空气环境下PtO2分解实验的研究

标准铂电阻温度计的感温元件高纯铂丝的氧化是影响其测温性能的重要因素之一。利用差示量热扫描仪(DSC)和X射线光电子能谱技术(XPS),研究铂丝氧化的主要产物PtO2在不同温度下的生成产物,以及不同产物的生成和分解温度。结果表明:当温度在550～820 ℃范围内时,随着温度的升高,PtO2会逐渐分解生成PtO和Pt,且温度越高生成的Pt含量越多;当温度高于820 ℃时,PtO2会快速分解为Pt和O2。该研究结果对标准铂电阻温度计的制作技术和使用提供了理论支撑。     

The Discontinuity in the First Derivative of the ITS-90 at the Triple Point of Water

This paper investigates the discontinuity in the derivative [dW/dT ₉₀]_TPW of the ITS-90 at the triple point of water, using data for over 40 calibrated standard platinum resistance thermometers (SPRTs). It finds that the discontinuity is in most cases somewhere between 0 and ?6 parts in 10⁵, in relative terms, but that the higher numerical values are obtained for ‘less ideal’ SPRTs (those with lower temperature coefficients of resistance), and also for sub-ranges not extending beyond the indium point. These results are investigated vis-à-vis the long-standing observation that the ITS-90 reference values W _r(Ga) and W _r(Hg) are not completely consistent with data for W(Ga) and W(Hg) for real SPRTs. It discusses what may be done in a future scale to ensure continuity in the first derivative, and it concludes with a comment about the acceptance criteria for SPRTs in the scale.