Effect of heat treatment on structure and properties of dispersed-type dental amalgam.
Effect of heat treatment of Ag-Cu-Pd dispersant particles on the structure, mechanical properties and mercury vapor release rate of an Ag-Cu-Sn/Ag-Cu-Pd-based dental amalgam has been investigated. Experimental results indicate that crystallinity of dispersant Ag-Cu-Pd alloy increases with increasing HTT, with most notable increase occurring between 100 and 200 degrees C. Increasing HTT of Ag-Cu-Pd alloy does not change much of the mercury/alloy ratio for amalgamation, but largely reduces working/setting time of the amalgam. The Ag-Cu-Pd particles in 7 d-aged amalgam are comprised primarily of an outer Sn/Cu/Pd-rich zone and an inner Ag/Cu/Pd-rich zone with eutectic-type morphology and chemical distribution. The annealing-enhanced Pd segregation effect is most significantly observed in the amalgam derived from 300 degrees C-annealed Ag-Cu-Pd dispersant. This amalgam also has the highest compressive strength, highest DTS, and lowest creep rate. Higher annealing temperature causes mechanical property of the amalgam to deteriorate. The initial mercury vapor release rates of amalgams derived from 100, 200 and 300 degrees C-annealed Ag-Cu-Pd dispersant are significantly lower than that derived from 400 degrees C-annealed dispersant.
Ju
Chien-Ping
CP
Department of Materials Science and Engineering, National Cheng-Kung University, No. 1, Da-Sha Road, Tainan 701, Taiwan, ROC.
Chen
Yu-Hsuan
YH
Ho
Wen-Fu
WF
Ho
Shu-Ching
SC
Chen
Wen-Cheng
WC
Shieh
Dar-Bin
DB
Chern Lin
Jiin-Huey
JH
D019245:Compressive Strength; D003300:Copper / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry; D003723:Dental Amalgam / Q000737:chemistry*; D006358:Hot Temperature; D008422:Materials Testing; D008628:Mercury / Q000737:chemistry; D010165:Palladium / Q000737:chemistry; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014961:X-Ray Diffraction
D003722:Dental Alloys; D012834:Silver; D010165:Palladium; D003300:Copper; D003723:Dental Amalgam; D008628:Mercury