The primary crystallite size of titania powder relates to its properties in a number of applications. Transmission electron microscopy was used in this interlaboratory comparison (ILC) to measure primary crystallite size and shape distributions for a commercial aggregated titania powder. Data of four size descriptors and two shape descriptors were evaluated across nine laboratories. Data repeatability and reproducibility was evaluated by analysis of variance. One-third of the laboratory pairs had similar size descriptor data, but 83% of the pairs had similar aspect ratio data. Scale descriptor distributions were generally unimodal and were well-described by lognormal reference models. Shape descriptor distributions were multi-modal but data visualization plots demonstrated that the Weibull distribution was preferred to the normal distribution. For the equivalent circular diameter size descriptor, measurement uncertainties of the lognormal distribution scale and width parameters were 9.5% and 22%, respectively. For the aspect ratio shape descriptor, the measurement uncertainties of the Weibull distribution scale and width parameters were 7.0% and 26%, respectively. Both measurement uncertainty estimates and data visualizations should be used to analyze size and shape distributions of particles on the nanoscale.

二氧化钛粉末的主要微晶尺寸与其在许多应用中的性能有关。在此实验室间比较（ILC）中使用透射电子显微镜来测量商业聚集的二氧化钛粉末的初晶尺寸和形状分布。在九个实验室中评估了四个大小描述符和两个形状描述符的数据。通过方差分析评估数据的可重复性和可重复性。三分之一的实验室对具有相似的尺寸描述符数据，但是83％的对具有相似的纵横比数据。尺度描述符分布通常是单峰的，并由对数正态参考模型很好地描述。形状描述符分布是多模式的，但数据可视化图表明，威布尔分布优于正态分布。对于等效圆直径尺寸描述符，对数正态分布比例尺和宽度参数的测量不确定度分别为9.5％和22％。对于长宽比形状描述符，Weibull分布比例和宽度参数的测量不确定度分别为7.0％和26％。测量不确定度估计和数据可视化都应用于分析纳米级粒子的大小和形状分布。