The effect of heat treatment on bonding strength of ceramic to cast nickel⁃chromium⁃based alloys

Abstract

Objective To explore the effect of heat treatments on the metal⁃ceramic bonding strength in Ni⁃Cr⁃Ti al⁃ loy and Ni⁃Cr alloy. Methods We evaluated the metal⁃ceramic bond strengths by using a three⁃points bending test ac⁃ cording to ISO 9693. Meanwhile, we also observed the metal⁃ceramic interface through scanning electronic microscope (SEM) and energy dispersive spectrum (EDS). Results The mean value of bonding strengths of four groups were (38.04 ± 3.79) MPa (Ni⁃Cr⁃Ti, degassed), (32.17 ± 4.00) MPa (Ni⁃Cr⁃Ti, no heat treatment), (36.32 ± 7.41) MPa (Ni⁃Cr, de⁃ gassed), (31.75±2.77) MPa (Ni⁃Cr, no heat treatment). The statistic analysis showed that the mean bonding strengths were affected significantly by heat treatment method (P = 0.001), but not alloy type (P = 0.484). SEM and EDS demon⁃ strated that the bonding surfaces of degassed specimens were compacted and had no cracks unlike those of specimens not receiving heat treatment. Conclusion According to the test results, the metal⁃ceramic bonding strengths of Ni⁃Cr⁃Ti alloy and Ni⁃Cr alloy are close to each other, and the bonding strengths of alloys can be heightened by heat treatment.

Keywords

• Porcelain fused metal
• Heat treatment
• Bonding strength
• Metal⁃ceramic interfacial characteris⁃ tic
• Three⁃points bending test