The Evalution Of Corrosion Behavior Of Five Metal-ceramic Alloys In Artificial Salivia

Objective:To evaluate the corrosion of five metal-ceramic alloys and explore the mechnism of the corrosion behavior in artificial salivia with SEM,AAS and XRPS.These alloys include Ni-Cr alloy,Ni-Cr alloy plated with golden, Ni-Cr alloy coupled with golden,Ti-6Al-4V alloy and precious-metal alloy.Methods:Five lamellar speciments were made of each alloy under PFM manufacture program.All speciments were dealed with finishing,sand blasting and polishing excepted of Ni-Cr alloy plated with golden and coupled with golden.Each speciment was cleaned by scrubbing with a soft toothbrush,rinsing with distilled water,and ultrasonic treatment in 75%alcohol,followed by two rinses with sterile double-distilled water to removed the alcohol.Then they were dried for at least 48h at 60℃.After soaked in artificial salivia at temperature of 37℃and pH of 6,each speciment was tested and analyzed with SEM and AAS in 1,3,6,12 weeks.All numerical data were analyzed with SPSS13.0 statistical software.Results:(1)Ion release was observed from every speciment throughout experiment.There were only some diffirences in the amount of mass released from thses five alloys.(2)The ion release rate of precious-metal alloy was the least,but rose with time.The initial rates of release appeared to be somewhat greater than those seen in later intervals,based on a slight change in the slopes of the mass-release curves.However,these changes were not significant statistically and were therefore unconfirmed.(3)The Au ion release rate of Ni-Cr alloy plated or coupled with golden was great and lasted.(4)The Ti release rate of Ti-6Al-4V alloy had poor detection limits relative to amounts which were likely to be released.But Ni and Cr release rate were very high.(5)There was scarely evidence of corrosion observed on the surface of precious-metal alloy through SEM.On the contrary,other alloys all had it.(6)There were Ni and Cr founded on the surface of these alloys but precious-metal alloy by X-ray Energy Spectrum.There was no Ti founded on the surface of Ti-6Al-4V alloy.Conclusion:(1)Each alloy releases ion in simulative oral environment.(2) Efficiency of precious-metal alloy is stable,ion release of it is small.(3)Because the integration between golden and Ni-Cr alloy is vulnerable,Ni-Cr alloy plated or coupled with golden both have not persistent corrosion resistence.(4) Ti-6Al-4V alloy is used so extensively.There are no distinguished differences on corrosion between general Ni-Cr alloy and it.(5)The Ni release rate of general Ni-Cr alloy is so massive that achieved mg/l level.