Effects of nano-AlN and sintering atmosphere on microstructure and properties of vitrified bond
Effects of nano-AlN and sintering atmosphere on microstructure and properties of vitrified bond
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DOI：
10.1016/j.compositesb.2011.01.020
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发表时间：
2011-06
影响因子：
13.1
通讯作者：
Yong-gai Hou;G. Qiao;Yong Shang;Wen-jun Zou;F. Xiao;B. Liao
中科院分区：
文献类型：
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作者：
Yong-gai Hou;G. Qiao;Yong Shang;Wen-jun Zou;F. Xiao;B. Liao
Na_2 O-B_2 O_3-SiO_2系玻璃具有低的热膨胀系数和低的熔点，适合于制造陶瓷结合剂超硬磨具。然而，其弯曲强度、断裂模式和化学耐久性较低。在陶瓷结合剂中加入氧化铝、氧化钙和氧化锌等添加剂，以改善磨具的性能。本文在Na 2 O-B2 O3-SiO2系陶瓷结合剂中添加了一种新型的纳米AlN添加剂，以改善陶瓷结合剂的组织和性能。在不同气氛下烧结了添加和不添加纳米AlN的Na 2 O-B2 O3-SiO2陶瓷结合剂。研究了纳米AlN和烧结气氛对Na 2 O-B2 O3-SiO2陶瓷结合剂组织和性能的影响。结果表明，在氩气保护下，添加6%纳米AlN的Na 2 O-B2 O3-SiO2复合材料的抗弯强度、冲击强度和耐磨性最高，这是因为纳米AlN作为晶核在烧结过程中促进了α-SiO2、β-SiO2和鳞石英的晶化。晶相的显微结构得到细化。纳米AlN陶瓷结合剂在空气中烧结时，纳米AlN粉末被氧化分解为Al 2 O3和气体。纳米AlN的分解使陶瓷结合剂的抗弯强度和耐磨性略有提高，但纳米AlN的分解增加了陶瓷结合剂中细小的闭孔数量和晶相尺寸，导致陶瓷结合剂的冲击强度降低。
The Na2O–B2O3–SiO2glass with low thermal expansion coefficient and melting point is suited to manufacture vitrified bond superhard grinding tool. However, its bending strength, fracture mode, and chemical durability are lower. Some additives, such as alumina, calcium and/or zinc oxides, and so on, were added in the vitrified bond in order to improve the property of grinding tool. In this work, a new additive of nano-AlN was added in Na2O–B2O3–SiO2vitrified bond for improving microstructure and properties of the vitrified bond. The Na2O–B2O3–SiO2vitrified bonds with and without nano-AlN were sintered at different atmosphere. The effects of nano-AlN and sintering atmosphere on the microstructure and properties of Na2O–B2O3–SiO2vitrified bonds were investigated. The results show that the highest bending strength, impact strength, and wear resistance were obtained when the Na2O–B2O3–SiO2with nano-AlN of 6% was sintered at argon, because nano-AlN as crystallization nucleus promotes the crystallization of α-SiO2, β-SiO2, and tridymite during sintering process. The microstructures of the crystalline phases were refined. When the vitrified bonds with nano-AlN were sintered at air, the nano-AlN powder was oxidated and decomposed into Al2O3and gas. The decomposition of nano-AlN increases slightly the bending strength and wear resistance of the vitrified bond due to the increasing amount of crystalline phase, but the decomposition of nano-AlN increases the amount of small close pores and size of crystalline phase, which results in the decreasing of impact strength of vitrified bond.