Abstract Porcelain-veneered Y-TZP fixed dental prostheses often fail from fracture and wear. Zirconia with its exceptional homogenous properties contributes to alleviate the failure. Powder injection molding (PIM) has long been found to enable a much more homogeneous microstructure to components when compared to those from die pressing. However, PIM parts, however, may have a slight difference in properties for different areas due to the nature of the injection process of the feedstock. In this study, zirconia dental ceramic parts were fabricated by the powder injection molding technique that utilizes a multi-component binder system consisting of paraffin, high density polyethylene, polypropylene, and stearic acid aiming to improve the behavior in the densification of powder shaping. The nano ZrO2 powders were firstly granulated before mixing to ensure good dispersion in the feedstock. The homogeneity of sintered zirconia was characterized by determining density and hardness of ten equally thick-section zirconia and four bars. The result showed that TZ-3YS-E zirconia obtained a sintering density of 6.05 g·cm− 3 and a hardness of 1300 HV0.5 with a small fluctuation sintered at 1475 °C. The homogeneity in the region away-from- gate was superior to the nearer-gate region based on evaluation of density, hardness, flexural strength and observation of microstructure, as well as the simulation of the mold filling of the feedstock. The average absolute deviation of hardness of slices 1 to 5 near the injection gate was 27.0 while that of slices 6 to 10 away from the injection gate was 14.0. The differences on the homogeneity and performances were regarded as the results of the drop of temperature and pressure in the final stage of mold filling of feedstock.

中文翻译：

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纳米氧化锆粉末注射成型的不均匀性研究

摘要 瓷贴面Y-TZP固定义齿经常因断裂和磨损而失效。氧化锆具有出色的均质特性，有助于减轻故障。长期以来，人们发现粉末注射成型 (PIM) 与模压成型相比，可以使部件的微观结构更加均匀。但是，由于原料注射过程的性质，PIM 部件在不同区域的性能可能略有不同。在这项研究中，氧化锆牙科陶瓷部件通过粉末注射成型技术制造，该技术利用由石蜡、高密度聚乙烯、聚丙烯和硬脂酸组成的多组分粘合剂系统，旨在改善粉末成型的致密化行为。纳米 ZrO2 粉末在混合前首先造粒，以确保在原料中的良好分散。烧结氧化锆的均匀性通过测定 10 个等厚截面氧化锆和 4 个棒的密度和硬度来表征。结果表明，TZ-3YS-E氧化锆在1475℃下烧结得到的烧结密度为6.05 g·cm- 3 ，硬度为1300 HV0.5，波动小。基于对密度、硬度、抗弯强度和微观结构观察的评估，以及对原料充模的模拟，远离浇口区域的均匀性优于近浇口区域。靠近注射口的1-5切片硬度平均绝对偏差为27.0，远离注射口的6-10切片硬度平均绝对偏差为14.0。