两种喷砂粒度对钯银合金金瓷结合强度的影响

Effects of two sizes of sandblasting on the metal-ceramic bonding strength of palladium-silver alloy

目的研究上瓷前不同粒度喷砂对钯银合金金瓷结合强度的影响。方法采用不同粒度(250、120μm)的Al2O3在0.3 MPa压力下,以45°角对钯银合金试件表面进行喷砂10 s粗化处理后,对合金表面的粗糙度、表面接触角进行检测。用ISO 9693规定的三点弯曲测试分别测定其金瓷试件的结合强度。两组表面粗糙度、表面接触角以及金瓷结合强度的数据使用独立样本t检验进行统计学分析(α=0.05)。使用有X线能谱分析的扫描电镜观察试件的显微特征,元素成分。结果250μm喷砂处理后钯银合金金属表面粗糙度2.03μm,接触角46.02°,与120μm喷砂处理后的表面粗糙度1.69μm、接触角63.61°比较,表面更为粗糙,润湿性更好。250μm组的金瓷结合强度为(51.61±5.91)MPa,120μm组的金瓷结合强度为(46.62±4.33)MPa,两者间差异有统计学意义(t=2.360,P=0.028)。三点弯曲测试后,所有开裂试件都为混合折裂模式。结论钯银合金在0.3 MPa压力下,250μm较120μm Al2O3喷砂后能获得较高的金瓷结合强度。

Objective To investigate the effect of size of sandblasting on metal-ceramic bonding strength of Pd-Ag alloy. Methods The surface roughness（Ra） and contact angle of Pd-Ag alloy surface were evaluated after using the different sizes of Al2O3（250, 120 μm） in 0.3 MPa air pressure to rough the alloy surface. The bond strengths were evaluated using a three-point bend test according to ISO 9693. The data of surface roughness, surface contact angle, and metal-ceramic bonding strength between two groups were analyzed using independent sample t-test（α = 0.05）. Scanning electron microscopy（SEM） equipped with energy dispersive X-ray spectroscopy（EDS） was used to evaluate microscopic features and elemental compositions. Results The mean surface roughness was 2.03 μm and the contact angle was 46.02° for sandblasted with 250 μm Al2O3 particles. Sandblasted with 250 μm Al2O3 provided rougher surface and better surface wettability than sandblasted with 120 μm Al2O3. The mean bonding strength of 250 μm sandblasting and 120 μm sandblasting group were（ 51.61 ± 5.91）and（ 46.62 ± 4.33） MPa, respectively. There was a statistically significant difference between two groups（t =2.360, P =0.028）. Mixture of adhesive and cohesive fracture modes were observed from fracture surfaces of all specimens. Conclusion Sandblasted with 250 μm Al2O3 obtain higher bond strengths than 120 μm in 0.3 MPa air pressure.