Laesecke Arno, Junker Clemens, Lauria Damian S
National Institute of Standards and Technology, Boulder, CO 80305, USA.
retired from NIST.
J Res Natl Inst Stand Technol. 2019 Feb 13;124:1-41. doi: 10.6028/jres.124.002. eCollection 2019.
The viscosities of three pentaerythritol tetraalkanoate ester base oils and one fully formulated lubricant were measured with an oscillating piston viscometer in the overall temperature range from 275 K to 450 K with pressures up to 137 MPa. The alkanoates were pentanoate, heptanoate, and nonanoate. Three sensing cylinders covering the combined viscosity range from 1 mPa·s to 100 mPa·s were calibrated with squalane. This required a re-correlation of a squalane viscosity data set in the literature that was measured with a vibrating wire viscometer, with an estimated extended uncertainty of 2 %, because the squalane viscosity formulations in the literature did not represent this data set within its experimental uncertainty. In addition, a new formulation for the viscosity of squalane at atmospheric pressure was developed that represents experimental data from 169.5 K to 473 K within their estimated uncertainty over a viscosity range of more than eleven orders of magnitude. The viscosity of squalane was measured over the entire viscometer range, and the results were used together with the squalane correlations to develop accurate calibrating functions for the instrument. The throughput of the instrument was tripled by a custom-developed LabVIEW application. The measured viscosity data for the ester base oils and the fully formulated lubricant were tabulated and compared with literature data. An unpublished viscosity data set for pentaerythritol tetrapentanoate measured in this laboratory in 2006 at atmospheric pressure from 253 K to 373 K agrees with the new data within their experimental uncertainty and confirms the deviations from the literature data. The density data measured in this project for the three base oils deviate from the literature data in a way that is by sign and magnitude consistent with the deviations of the viscosity data. This points to differences in the sample compositions as the most likely cause for the deviations.
使用振荡活塞粘度计在275 K至450 K的整体温度范围内、高达137 MPa的压力下，测量了三种季戊四醇四链烷酸酯基础油和一种全配方润滑剂的粘度。链烷酸酯分别为戊酸酯、庚酸酯和壬酸酯。用角鲨烷对覆盖1 mPa·s至100 mPa·s组合粘度范围的三个传感缸进行了校准。这需要对文献中用振弦粘度计测量的角鲨烷粘度数据集进行重新关联，估计扩展不确定度为2%，因为文献中的角鲨烷粘度公式在其实验不确定度范围内不能代表该数据集。此外，还开发了一种新的大气压下角鲨烷粘度公式，该公式在超过11个数量级的粘度范围内，在估计不确定度内表示了169.5 K至473 K的实验数据。在整个粘度计范围内测量了角鲨烷的粘度，并将结果与角鲨烷相关性一起用于开发仪器的精确校准函数。通过定制开发的LabVIEW应用程序，仪器的通量提高了两倍。将酯类基础油和全配方润滑剂的测量粘度数据制成表格，并与文献数据进行比较。2006年在本实验室于大气压下在253 K至373 K测量的季戊四醇四戊酸酯未发表的粘度数据集在实验不确定度内与新数据一致，并证实了与文献数据的偏差。本项目中测量的三种基础油的密度数据与文献数据的偏差在符号和大小上与粘度数据的偏差一致。这表明样品成分的差异是偏差最可能的原因。
