钛表面的氧化对钛瓷结合强度的影响

研究了钛表面氧化对钛/瓷结合强度的影响, 并采用溶胶凝胶技术在钛表面制备SnO_x中间层, 研究SnO_x层对钛/瓷结合强度的影响. 结果表明：空气炉中800℃氧化3min后, 钛/瓷结合强度明显下降; 烤瓷炉中预氧化3min, 钛/瓷结合强度无明显变化. 热处理使钛表面生成一层金红石型氧化层, 钛/瓷剥脱主要发生在金红石氧化层与钛之间. 采用溶胶-凝胶法经300℃处理后在钛表面制得的SnO_x涂层, 可有效隔绝氧向Ti表面的扩散, 防止钛表面的过度氧化, 提高了钛/瓷结合强度. 经SnO_x涂层处理后, 钛/瓷剥脱主要发生在SnO_x涂层内.

Effect of Titanium Surface Oxidation on the Bonding Strength of Ti-Porcelain

Effects of titanium surface oxidation on titanium-ceramic adhesion were investigated. Cast pure titanium was subjected to pre-oxidation and introduction of an intermediate layer of SnO_x by sol-gel process. Specimen surfaces were characterized by XRD and SEM/EDS. The adhesion between the titanium and porcelain was evaluated by three-point flexure bond test. A rutile layer is formed on the titanium surface after pre-oxidation. Failure of the titanium-porcelain with pre-oxidation treatment predominantly occurs at the titanium-oxide interface. Pre-oxidation treatment does not affect the fracture mode of the titanium-porcelain system. The rutile layer is more strongly bonded to the porcelain than titanium. The poor adhesion of the rutile with substrate is due to the thermal stress arising from the large lattice mismatch and difference in coefficient of thermal expansion between Ti and rutile during cooling. However, a thin and coherent SnO_x film with small spherical pores obtained after heat-treated at 300℃ serves as an effective oxygen diffusion barrier to improve titanium-ceramic adhesion. The SnO_x films change the fracture mode of the titanium-porcelain system and improve the mechanical and chemical bonding between porcelain and titanium, resulting in the increased bonding strength of titanium-porcelain.