Abstract:
Objective To compare the corrosion resistance and the mechanical stability after corrosion of 3D printing and cast cobalt-chromium (Co-Cr) alloy.
Methods The Co-Cr alloys were fabricated by the selective laser melting (SLM) technique and casting technique with suitable parameters, seventy-two specimens were prepared and divided into 12 groups (n= 6) by random number method. Static immersion test was used to evaluate corrosion resistance and the effect of the corrosion on the mechanical stability of the alloys. Surface roughness (Ra) , vickers hardness (VHN) , tensile strength (TS) and bending strength (BS) of the samples were analyzed separately by confocal laser scanning microscope (CLSM) , vicker microhardness tester, universal testing machine. The results were analyzed by 2×2 factorial design analysis of variance (α= 0.05) , the pairwise comparison was performed with Bonferroni method.
Results Manufacturing methods and corrosion had no interaction effects on Ra and BS (FRa= 2.989, PRa= 0.099; FBS= 0.480, PBS= 0.496) . The two factors′ main effects on Ra had significant differences (Fmethod= 6.262, Pmethod= 0.021; Fcorrosion= 6.581, Pcorrosion= 0.018) . The Ra of 3D group was lower than that of cast group [Ra3D= (0.084 ± 0.026) μm, Racast= (0.111 ± 0.024) μm]. The Ra of contrast group was lower than that of corrosion group[Racontrast= (0.084 ± 0.025) μm, Racorrosion= (0.111 ± 0.025) μm]. The two factors′ main effects on BS had significant differences (Fmethod= 6.753, Pmethod= 0.013; Fcorrosion= 7.384, Pcorrosion= 0.017) . The BS of 3D group was higher than that of cast group [BS3D= (1651 ± 242) MPa, BScast= (1371 ± 252) MPa]. The BS of contrast group was higher than that of corrosion group [BScontrast= (1645 ± 183) MPa, BScorrosion= (1377 ± 310) MPa]. Manufacturing methods and corrosion had interaction effects on VHN and TS (FVHN= 5.018, PVHN= 0.037; FTS= 5.903, PTS= 0.025) . The results of the pairwise comparison of Bonferroni method suggested significant differences on VHN and TS (PVHN<0.001, PTS<0.001) were found between the 3D contrast group [VHN3D= (469 ± 4) HV, TS3D= (1010 ± 46) MPa] and the cast contrast group [VHNcast= (418 ± 4) HV, TScast= (827 ± 25) MPa], significant differences on VHN and TS (PVHN<0.001, PTS<0.001) were observed between the 3D corrosion group [VHN3D= (418 ± 3) HV, TS3D= (985 ± 30) MPa] and the cast corrosion group [VHNcast= (375 ± 5) HV, TScast= (728 ± 45) MPa]. Significant differences on VHN (P<0.001) were found between the 3D contrast group and the 3D corrosion group. No significant differences on TS (P= 1.000) were found between the 3D contrast group and the 3D corrosion group. Significant differences on VHN and TS (PVHN<0.001, PTS<0.001) were observed between the cast contrast group and the cast corrosion group.
Conclusions The 3D printing Co-Cr alloy has better corrosion resistance than that of the cast Co-Cr alloy. The 3D printing Co-Cr alloy has better stability of the TS and BS than that of the cast Co-Cr alloy. Both kinds of alloys have equal stability of VHN.
Key words:
3D printing,
Selective laser melting,
Cobalt-chromium alloy,
Corrosion resistance,
Mechanical stability
Xiaoyu Li, Meihua Zheng, Jieqi Wang, Guicheng Yang, Tao He, Jingsong Li, Song Fan. Comparison of the corrosion resistance and the mechanical stability after corrosion of 3D printing and cast cobalt-chromium alloy[J]. Chinese Journal of Stomatological Research(Electronic Edition), 2016, 10(05): 327-332.