scholarly journals Corrosion Resistance of Cr–Co Alloys Subjected to Porcelain Firing Heat Treatment—In Vitro Study

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 636
Author(s):  
Dorota Rylska ◽  
Bartłomiej Januszewicz ◽  
Grzegorz Sokołowski ◽  
Jerzy Sokołowski
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
In Vitro Study ◽  
Alloying Elements ◽  
Dental Ceramics ◽  
Cobalt Chromium ◽  
Corrosion Properties ◽  
Manufacturing Method

The procedure of ceramics fusion to cobalt–chromium (Co–Cr) base dental crowns affects their corrosion behavior and biological tolerance. This study’s purpose was to comparatively evaluate the effect of heat treatment (HT) applicable for dental ceramics firing on the corrosion properties among Co–Cr base alloys fabricated via different methods: casting (CST), milling soft metal and post sintering (MSM), and selective laser melting (SLM). All specimens were subjected to a heat treatment corresponding to a full firing schedule. The microstructure and elemental composition of oxidized surfaces were investigated by scanning electron microscopy and energy dispersive spectroscopy. Corrosion properties were examined by electrochemical potentiodynamic polarization tests. The values of jcorr, Ecorr, Rp, and breakdown potential Ebr were estimated. The oxide layers formed during the HT process corresponded to the composition of the original alloys’ structure. Among the thermal treated alloys, SLM showed the highest corrosion resistance, followed by the MSM and CST. This may be attributed to uniform distribution of alloying elements in homogenous structure and to the reduced porosity, which enhances corrosion resistance and decreases the risk of crevice corrosion. The overall corrosion behavior was strongly influenced by the segregation of alloying elements in the microstructure, thus, is directly determined by the manufacturing method.

Effect of Ozone on Corrosion Behavior of a Cobalt–Chromium Alloy Used in Removable Partial Denture Framework: An In Vitro Study

2021 ◽  
pp. 232020682110157
Author(s):  
Abdolrasoul Rangrazi ◽  
Amirtaher Mirmortazavi ◽  
Reyhaneh Imani ◽  
Davood Nodehi
Keyword(s):  
Corrosion Resistance ◽  
Inductively Coupled Plasma ◽  
In Vitro Study ◽  
Optical Emission ◽  
Cobalt Chromium ◽  
Inductively Coupled ◽  
Significant Difference ◽  
Polarization Test ◽  
Ozonated Water

Aim: The aim of this study was to evaluate the effect of the ozonated water on corrosion of a cobalt–chromium (Co-Cr)-based alloy, which is applied for the fabrication of metal frameworks of removable partial dentures. Materials and Methods: In this in vitro study, a total of 30 disk-shaped samples of a Co-Cr alloy were papered and randomly divided into two groups of 15 specimens. In group 1 (control), the specimens were stored in distilled water (DW), and in group 2, the specimens were stored in ozonated water. Around 90 immersions were performed, and the weight change of each specimen was determined. The ion release was analyzed using an inductively coupled plasma-optical emission spectrophotometer. The potentiodynamic polarization test was performed for each group to assess the corrosion resistance of the Co-Cr alloy. The statistical analysis was performed using SPSS version 22. Data were analyzed by independent samples’ t-test. Results: The results showed no significant difference between the weight changes of the two groups. The test using an inductively coupled plasma-optical emission spectrophotometer demonstrated no significant difference between the groups in Co and Cr ions release. In the potentiodynamic polarization test, both groups present similar corrosion behavior, and ozonated water has no deleterious effect on the corrosion resistance and passive range of the Co-Cr alloy compared to DW. Conclusion: As compared to DW, ozonated water has no significant deleterious effect on the corrosion resistance of the Co-Cr frameworks and can be used for cleaning the removable partial dentures.

Corrosion behavior of new type Co-based superalloys with different Ni contents

2017 ◽  
Vol 35 (6) ◽  
pp. 455-462 ◽  
Author(s):  
Bo Gao ◽  
Lei Wang ◽  
Yang Liu ◽  
Xiu Song ◽  
Shu-Yu Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Corrosion Layer ◽  
Corrosion Process ◽  
Corrosion Properties ◽  
Oxidation Processes ◽  
Ni Content ◽  
Ni Addition ◽  
New Type

AbstractThe corrosion properties of γ′-strengthened Co-xNi-Al-W-Cr (where x=15, 20, 25, and 30 at.%) superalloys were investigated in the mixture of 75 wt.% Na2SO4+25 wt.% NaCl at 900°C. The results showed that the corrosion behavior is associated with both sulfuration and oxidation processes. It was demonstrated that increasing the addition of Ni effectively promoted the formation of continuous Al2O3 scales, so that the hot corrosion resistance could be improved. When Ni content is more than 20 at.%, a large amount of Ni3S2 precipitates during the corrosion process. Sulfuration can destroy the integrity of the corrosion layer and increase the activity of oxygen. In this way, the internal oxidation of the alloys becomes more serious. Therefore, it is recommended that the optimum Ni addition is about 20 at.% for new type Co-Ni-Al-W-Cr superalloys.

scholarly journals Efficacy of Organic Component on Hardness and Fracture Toughness of Human Dentin Using Heat treatment – In vitro Study

2016 ◽  
Vol 9 (3) ◽  
pp. 1101-1105
Author(s):  
RAMACHANDRAN TAMILSELVI ◽  
RAJENDRAN MATHAN RAJAN ◽  
VERONICA ARUNA KUMARI ◽  
DEIVANAYAGAM KANDASWAMY
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
In Vitro Study ◽  
Vitro Study ◽  
Organic Component ◽  
Human Dentin

scholarly journals Influence of Luting Materials on the Retention of Cemented Implant-Supported Crowns: An In Vitro Study

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1853 ◽  
Author(s):  
Ella Naumova ◽  
Felix Roth ◽  
Berit Geis ◽  
Christine Baulig ◽  
Wolfgang Arnold ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
In Vitro Study ◽  
Storage Conditions ◽  
Glass Ionomer Cements ◽  
Glass Ionomer ◽  
Cobalt Chromium ◽  
Retention Force ◽  
Implant Abutments ◽  
Aging Conditions

The retention force of cemented crowns on implant abutments with various luting materials was evaluated. Cobalt–chromium crowns were cemented onto tapered titanium abutments (Camlog) with eugenol-free temporary cement (RelyX TempBond NE), composite-based temporary cement (Bifix Temp), zinc phosphate cement (Harvard Cement), glass-ionomer cements (Meron, Fuji I), and resin-modified glass-ionomer cements (Fuji II, Fuji Plus, Ketac Cem Plus). Specimen aging via hydrostress was performed in artificial saliva at 37 °C for 14 days (S1), followed by hydrothermal stress with thermocycling (S2). The crowns were removed, and the force was recorded (T1). Subsequently, the crowns were recemented, aged, and removed, and the force was recorded (T2, T3). The retention forces differences were statistically significant according to the storage conditions at T1 (p = 0.002) and T3 (p = 0.0002). After aging (S1), Ketac Cem Plus had the highest retention force median value difference (T3 versus T1) (−773 N), whereas RelyX TempBond NE had the lowest (−146 N). After aging (S2), Meron had the highest retention force median value difference (−783 N), whereas RelyX TempBond NE had the lowest (−168 N). Recementation decreased the retention force of the implant-supported cobalt–chromium crowns cemented and recemented with the same luting materials. Luting materials (at T1) and aging conditions significantly impacted the retention force.

Effects of hydroxyapatite content on mechanical properties and in-vitro corrosion behavior of ZK60/HA composites

2020 ◽  
Vol 111 (8) ◽  
pp. 621-631
Author(s):  
Jie Teng ◽  
Zili Xu ◽  
Jinlong Su ◽  
Yuan Li
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Measurement ◽  
X Ray Diffraction ◽  
Corrosion Morphology ◽  
Hardness Tests ◽  
Zk60 Alloy ◽  
Immersion Testing

Abstract In this study, hydroxyapatite-reinforced ZK60 Mg alloybased composites were fabricated via a powder metallurgy route. The mechanical properties of these composites were studied by compressive tests and hardness tests. The in-vitro corrosion behavior was also investigated using immersion testing and electrochemical measurement. The influence of hydroxyapatite content on the mechanical properties and invitro corrosion behavior was evaluated. The microstructure and corrosion morphology were characterized by means of X-ray diffraction, optical and scanning electron microscopy. The results showed that the composite materials with 10 wt.% hydroxyapatite exhibited a better combination of mechanical strength and corrosion resistance. Compared with ZK60 alloy, the addition of 10 wt.% hydroxyapatite resulted in an increase in corrosion resistance by 38.6%.

Sign in / Sign up

Export Citation Format

Share Document