Objective In this work, we aim to determine the optimum pH value for the preparation of 3% yttria-stabilized tetragonal zirconia polycrystalline (3Y-TZP)/3%Al2O3 and optimum calcination temperature of Al2O3 precursor and amorphous boron nitride (BN) for Al2O3-BN coating 3Y-TZP powders.Methods The 3Y-TZP/3%Al2O3 composite powders were prepared through the heterogeneous precipitation method under different pH values (6.5, 7.5, 8.5, and 9.5) and analyzed through trans-mission electron microscopy (TEM) to determine the optimum coating morphology. Al2O3 precursor, which was prepared under the optimum pH value, was calcined at different temperatures (800, 1000, 1200, and 1400℃). The amorphous BN coating 3Y-TZP/3%Al2O3 powder was prepared via in situ reaction with boric acid and urea (calcined with N2 at 850℃ for 5 and 3 h and 800℃ for 5 and 3 h). TEM, energy dispersive spectrometry (EDS), and X-ray diffraction (XRD) were performed to characterize the results.Results The optimum coating morphology was obtained at 8.5 pH. When the Al2O3 precur-sor was calcined at 1200℃ and coated with BN (calcined with N2 at 800℃ for 5 h), the Al-B-O compound was less, and t-ZrO2 was more represented.Conclusion The optimum pH value for 3Y-TZP/3%Al2O3 composite preparation is 8.5. For the preparation of Al2O3-BN coating 3Y-TZP powders, the optimum calcination temperature of the Al2O3 precursor and amorphous BN are 1200 and 800℃, respectively.%目的 研究非均相沉淀法制备3%氧化钇稳定的四方氧化锆多晶陶瓷(3Y-TZP)/3%Al2O3复合粉的最佳pH值;3Y-TZP/3%Al2O3/10%BN双相包覆中,合成Al2O3及非晶氮化硼(BN)的最佳热处理温度.方法 不同pH值(6.5、7.5、8.5、9.5)下,通过非均相沉淀法合成Al2O3前驱体包覆3Y-TZP粉,通过透射电镜(TEM)选出包覆形貌较均匀的一组.将此pH下制备的复合粉经不同的温度(800、1000、1200、1400℃)处理后,硼酸尿素反应烧结法(N2保护下,850℃煅烧5 h,850℃煅烧3 h及800℃煅烧5 h,800℃煅烧3 h)合成10%BN包覆3Y-TZP/3%Al2O3粉,通过TEM、能谱分析及X射线衍射(XRD)选出形貌及相组成最佳的一组.结果 当pH值为8.5时,3%Al2O3前驱体均匀地包覆在3Y-TZP颗粒周围;3%Al2O3前驱体经1200℃煅烧,再包覆10%BN,在N2保护下800℃煅烧5 h,此时可见3Y-TZP颗粒周围包覆Al2O3及非晶BN,3Y-TZP/3%Al2O3/10%BN复合粉中Al-B-O化合物较少,且t-ZrO2所占的比例最多.结论 合成Al2O3前驱体包覆3Y-TZP的最佳pH值为8.5;双相包覆中,Al2O3前驱体的最佳处理温度为1200℃,合成非晶BN的适宜条件为N2保护下800℃煅烧5 h.
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